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Abstract

To determine the feasibility of a randomized controlled trial (RCT) testing the efficacy of psychologically-informed physiotherapy (PIPT), which includes usual physiotherapy (UP) interventions, compared with UP, and to explore the preliminary effectiveness of the interventions.

People with chronic low back pain at high risk of poor prognosis (using the Start Back screening tool) were recruited and allocated to PIPT or UP. Effectiveness of recruitment strategies, adherence to intervention, risk of contamination, and specific challenges were assessed. Functional capacity, pain, quality of life, kinesiophobia, catastrophization, central sensitization, and self-efficacy were measured at baseline, 6-, 12- and 24-week follow-ups.

Forty participants were recruited mainly by diffusing through Laval University's email list, and 10 physiotherapists treated the participants recruited. The retention rate of participants at 24 weeks was 72.5%. Adherence to treatment by participants and physiotherapists was very good. The risk of contamination was low, and the specific challenges identified were modifiable. Significant improvement over time in all clinical variables of interest, except self-efficacy, was observed with no difference between groups.

As most success criteria were met, conducting an RCT evaluating PIPT and PU is feasible with modifications. PIPT and UP appear to be similarly effective.

Résumé

déterminer la faisabilité d’une étude randomisée et contrôlée (ÉRC) évaluant l’efficacité de la physiothérapie fondée sur la psychologie (PTFP), qui inclut les interventions de physiothérapie conventionelle (PC), par rapport à la PC, et explorer l’efficacité préliminaire des interventions.

les chercheurs ont recruté des personnes qui souffrent de douleurs lombaires chroniques, ayant une probabilité élevée de mauvais pronostic (au moyen de l’outil de dépistage Start Back) et les ont réparties entre la PTFP et la PC. Ils ont évalué l’efficacité des stratégies de recrutement, l’adhésion à l’intervention, le risque de contamination et les difficultés particulières. Ils ont également mesuré la capacité fonctionnelle, la douleur, la qualité de vie, la kinésiophobie, la catastrophisation, la sensibilisation centrale et l’autoefficacité en début d’étude ainsi que lors des suivis à six, 12 et 24 semaines.

les chercheurs ont recruté 40 participants, principalement en diffusant le projet par courriel à la communauté de l’Université Laval, et dix physiothérapeutes les ont traités. Le taux de rétention des participants était de 72,5 % à 24 semaines. Les participants et les physiothérapeutes ont démontré une très bonne adhésion au traitement. Le risque de contamination était faible, et les difficultés particulières constatées pouvaient être modifiées. Les chercheurs ont observé une amélioration considérable au fil du temps pour toutes les variables cliniques d’intérêt, sauf l’autoefficacité, sans différence entre les groupes.

puisque la plupart des critères de succès étaient respectés, il est faisable de réaliser une ÉRC pour évaluer la PTFP et la PU, sous réserve de modifications. La PTFP et la PC semblent avoir une efficacité similaire.

Low back pain (LBP) is characterized by the presence of pain between the 12th rib and the gluteal fold, with or without radiation to the lower extremity.1 Since a specific cause of LBP cannot be identified in approximately 90% of patients, this condition is labelled non-specific LBP.2 Once the pain duration exceeds 3 months, LBP is considered chronic.3 Chronic non-specific LBP (CLBP) is highly prevalent, affecting 19.6% of individuals aged 20–59 years.4 As the leading cause of disability worldwide,5 its impact on healthcare systems is major and innovative solutions to optimise management are needed.

The effect of conventional interventions to manage CLBP are modest at best.6 Indeed, even for intervention recommended by clinical practice guidelines (e.g., exercises, education, manual therapy), effect sizes are small to moderate.7,8 Low-risk high-value interventions that can be personalized with risk-stratified management strategies may improve the effect size. Indeed, by taking into account the unique biopsychosocial profile of each individual,9 risk-stratified management provides the opportunity to target specific interventions to subgroups of patients based on their risk of poor prognosis.10 To facilitate the use of this approach by clinicians, the STarT Back Screening Tool was developed. It consists of a 9-question screening tool identifying modifiable indicators of poor prognosis, that is, on which a treatment can have an effect (i.e., leg pain, co-morbid pain, disability, bothersomeness, catastrophising, fear, anxiety, and depression) and taking only 2 minutes to complete.11 Although the STarT Back model is not the only stratified care approach existing, it is one of the most used because of its simplicity and validity.10 The STarT Back tool can determine the risk of future poor outcomes (low, medium, and high) among people with LBP.11 The risk level is calculated using the total score and the psychosocial subscore comprising the five questions assessing potential psychosocial contribution to pain and disability.11 Specifically, a patient is considered at low risk level if the total score is ≤3, at medium risk if the total score is ≥4 and the subscore ≤3, and at high risk if the total score is ≥4 and the subscore ≥4. Thus, people classified as being at high risk of poor prognosis have a high contribution of psychosocial factors to their pain.12 Based on the classification, tailored interventions are offered to patients, that is, advice to stay active and general education are prescribed to patients at low-risk, evidence-based physiotherapy to medium-risk, and psychologically-informed physiotherapy to high-risk to mitigate psychosocial contributors to pain.13

Psychologically-informed practice is an approach that integrates physical, behavioural, and psychological interventions to reduce pain and disability.14 It can be delivered by a variety of health care professionals, including physiotherapists; it is then referred to as psychologically-informed physiotherapy (PIPT).15 Cognitive-behavioural therapy is a psychotherapy widely practiced throughout the world. PIPT is not cognitive-behavioural therapy. As such, it is not a psychotherapy, but rather a physiotherapy approach that focuses more on the patient's overall health. In practical terms, PIPT integrates physical treatments (e.g., spinal manipulation or exercises) with interventions based on cognitive-behavioural principles (e.g., pain adaptation techniques or progressive relaxation).15 PIPT is based on cognitive behavioural therapy principles, which effectiveness to improve low back pain is supported by the literature.16 Training physiotherapists to detect and mitigate factors associated with a high risk of poor prognosis – such as fear of movement and catastrophizing – may improve treatment efficacy in CLBP. Patients having more psychosocial contributors to pain (i.e., at high-risk) are often refractory to conventional treatments,17 consume more healthcare resources,5 then, necessitate interventions that mitigate the impact of these contributors. Improving treatment success with this specific CLBP population is then paramount. Although some studies observed promising results in terms of disability, pain, time off work, and health care costs of the STarT Back approach in CLBP to manage patients at high risk of poor prognosis,18,19 others did not,20,21 which supports the relevance of another clinical trial on the subject. Authors suggest that major implementation problems may explain the absence of results.15 Thus, it seems critical to verify the feasibility to perform a clinical trial including PIPT in the context of Quebec, Canada.

The main aim of this project is to determine the feasibility to perform a randomised controlled trial (RCT) testing the efficacy of a PIPT intervention in people with CLBP at high risk of poor prognosis according to the Start Back Screening Tool, compared to usual physiotherapy (UP). Specific aims are to assess (i) strategies to recruit participants and physiotherapists (recruitment rate and retention), (ii) physiotherapists and participants adherence to intervention, (iii) the risk of contamination between treatment sites, and (iv) specific challenges. As a secondary objective, effects of interventions on clinical variables will also be explored.

Design

A 2-arm randomized clinical feasibility trial with a 6-month follow-up was conducted with an allocation ratio of 1:1. Treating physiotherapists in each arm worked in two different private clinics (Physio Interactive group, Quebec City, Canada – urban setting) to limit contamination. The study design followed the CONSORT extension for pilot or feasibility trial.22 The protocol was prospectively registered in ClinicalTrials (NCT04979403). Research Electronic Data Capture (REDCap)1, a secure web-based platform for creating and managing online databases and surveys,23 was used for self-reported questionnaires at baseline, 6 weeks, 12 weeks, and 24 weeks after study inclusion. The study was approved by the Ethics Research Committee of the Centre Intégré Universitaire de Santé et de Services Sociaux de la Capitale-Nationale (Project: # 2021-2227), according to the Declaration of Helsinki. All participants provided their written informed consent prior to their inclusion in the clinical trial.

Recruitment of clinics and clinicians

The recruitment of two physiotherapy clinics was deemed sufficient to meet the project objectives. Therefore, the project was conveniently presented in June 2021 to the Physio Interactive clinic co-owners, who agreed to participate in the project. Next, the objectives of the research project were broadly presented to the physiotherapists at two different branches of this clinic, that is, one for UP and the other for PIPT. Physiotherapists interested in the project and available for the training session were recruited.

Recruitment of participants

Participants were recruited between July 2021 and March 2022 from the waiting lists of the Institut de Réadaptation en Déficience Physique du Québec (IRDPQ) musculoskeletal injury unit and of the Centre d’expertise en Gestion de la Douleur Chronique du Centre Hospitalier Universitaire de Québec - Université Laval (CHU) pain clinic, from the Quebec Back Pain consortium,24 from email diffusion to students and workers from Université Laval, and from a list of participants who had completed other projects of the research team. The recruitment advertisement was also posted on social media. People actively seeking care (e.g., waiting lists) and not actively seeking care (e.g., social media) were recruited. Participants interested in the study were contacted to establish their eligibility through RedCap and a phone call. Inclusion criteria were age between 18 and 65 years, non-specific CLBP (>3 months), and a high risk of poor prognosis according to the STarT Back Screening Tool (i.e., ≥4 on psychosocial subscore). Exclusion criteria were any specific cause of low back pain (e.g., fracture, cancer, infection, inflammatory disease, cauda equina syndrome, pregnancy-related lumbopelvic pain),2 ongoing litigation, or neuropathic pain (≥ 4 on the Douleur Neuropathique 4 (DN4) questionnaire).25 During the first month of recruitment, most participants were excluded due to the exclusion criterion of work absenteeism (that was initially stated on ClinicalTrials). At this point, recruitment was very difficult. The decision was therefore taken, in the interests of recruitment and to be representative of the target population, to remove the exclusion criterion of work absenteeism 1 month after the start of recruitment. At baseline, sociodemographic factors were collected with the Canadian Minimum Dataset for CLBP research was used to collect age, gender, duration of LBP, lumbar surgery, treatment used for LBP, employment status, and education level to characterize both groups.26,27

Interventions

Each intervention consisted of eight sessions spread over 11 weeks, precisely a 60-minute assessment meeting and a follow-up session during the 1st week, followed by weekly follow-up sessions until the 6th week, and a final follow-up session (i.e., “booster” session) at the 11th week. The purpose of a booster session was to revisit and reinforce participants’ understanding, abilities, and attitudes regarding the essential elements of the intervention.28 The duration of each follow-up was 30 or 45 minutes, at the physiotherapist's discretion. Physiotherapists of both groups had access to an expert clinician (mentor) for two 30-minute meetings per participant as needed. For both groups, interventions were based on clinical judgment of the physiotherapist and tailored to the participant needs.

Usual physiotherapy

The physiotherapists of the UP group participated in a 2-hour training summarizing the recommendations for assessment and treatment of recent clinical practice guidelines in CLBP.16,2933 This training was delivered by the research team (AD, PL, HMA) and provided before the start of the recruitment of participants. A summary of the recommendations was provided to physiotherapists for future reference. Although all interventions that a physiotherapist can provide in the province of Quebec were allowed (e.g., education, advice to stay active, exercises, manual therapy), they were encouraged to use evidence-based recommendations from clinical guidelines. This decision was taken to better represent clinical practice.

Psychologically-informed physiotherapy

Physiotherapists of the PIPT group participated in a 2-day training in hybrid format provided by a physiotherapist with expertise in this approach (AG). The main objective of this training was to identify biopsychosocial factors that impede recovery and to intervene on these factors within the physiotherapist's scope of practice. Delivered online, the first part of the structured training focused on identifying psychosocial factors contributing to pain and disability and limiting the success of CLBP interventions, such as bothersomeness, catastrophizing, fear, anxiety, and depression. Delivered in person, the second part of the training addressed theoretical concepts and strategies for implementing interventions that may help to mitigate psychosocial barriers:

Establishing common goals with the patient to ensure collaboration between healthcare provider and the person with pain in setting joint objectives to enhance compliance with treatment and patient engagement;

Establishment of the therapeutic alliance to create an effective therapeutic partnership.

Behaviour change model strategies to facilitate positive behavioural modifications among patients and encourage healthier habits and actions;

Motivational interview to elicit and reinforce motivation to make positive changes in lifestyle or behaviour;

Education on pain neurophysiology to enable people with pain to better manage pain by themselves;

Gradual exposure to pain triggers to enable patients to gradually build resilience and decrease sensitivity over time;

Stress management techniques such as breathing techniques to contribute to a healthier lifestyle.

All these interventions were taught with specific strategies to implement them in private clinic settings. All interventions that a physiotherapist can provide in the province of Quebec were allowed.

Outcomes
Feasibility outcomes

The primary outcomes of this study focused on feasibility.

(i)

Efficacy of the recruitment strategies: Efficacy of strategies to recruit participants was measured with the number and percentage of participants assessed, eligible, and recruited by recruitment source. The number of physiotherapists contacted and recruited by branch of the clinic was used as a measure of efficacy.

(ii)

Adherence to intervention: Participant's adherence to intervention was assessed with the number of appointments completed per participant (median) and with a self-administered standardized question (“Overall, how rigorously do you think you followed the plan of physiotherapy treatment [recommendations, exercises, etc.]?”) at the 6th week on a 11-level scale from 0 (I didn’t follow the plan) to 10 (I followed the plan most rigorously). Given the importance of thoroughly documenting the tested interventions, both for article comprehension and reproducibility purposes, a checklist was created and used for each study group (see Checklist in Supplementary material). Physiotherapist's adherence to intervention was measured by the completion of the checklist documenting the number of minutes achieved per session by type of intervention performed (e.g., for the UP group: education, exercises, manual therapy, other interventions; for the PIPT group: the same interventions as the UP group and specific biopsychosocial interventions learnt from the training). This checklist permitted to document the percentage of time devoted to identify/mitigate psychosocial factors on the total time devoted to interventions for both groups. Moreover, the median number of participants treated by physiotherapist and mean appointment time in minutes were calculated.

(iii)

The risk of contamination between treatment sites was assessed in four questions and specific challenges, in five questions, during 20-minutes individual semi-structured interviews with physiotherapists after the end of the intervention (see Interview guide in Supplementary materials).

Self-reported outcomes

Self-reported outcome measures were selected based on experts’ recommendations on the core outcomes to measure pain, physical functioning, and health-related quality of life for CLBP studies.34 Table 1 reports constructs tested for each outcome, the instrument, the score range, and the cut-off that indicates high-level/presence of the construct, when applicable.3537 All self-reported questionnaires are reliable and valid.3846

Table

Table 1 Self-Reported Outcomes

Table 1 Self-Reported Outcomes

Construct Instrument Scores High score represents Cut-off*
Primary outcome
Physical functioning Oswestry Disability Index 0–100 More disability
Secondary outcomes
Pain Numeric rating scale 0–10 More pain
Quality of life SF-12 (V2) physical and mental scores 0–100 Better quality of life
Kinesiophobia Tampa Scale of Kinesiophobia 11–44 More kinesiophobia 36
Pain Catastrophizing Pain Catastrophizing Scale 0–52 More catastrophizing 30
Symptoms of central sensitization Central Sensitization Inventory (9 items) 0–36 More symptoms of central sensitization 20
Self-Efficacy Chronic Pain Self-Efficacy Scale 0–10 Better self-efficacy
Expectations for pain 7-point Likert scale −3 to 3 Better expectation for pain reduction
Perception of change Global Rating of Change −5 to 5 More improvement of the condition

*Cut-off indicates high-level/presence of the construct.

SF-12 (V2) = Short form 12 items health survey (second version)

Sample size

A sample size calculation is not required for feasibility studies.47 Based on generally accepted sample sizes of 10–40 participants per group for pilot studies,48 and the need to document the feasibility of the project, a sample size of 30–40 participants was considered acceptable.

Randomization

A random allocation sequence was generated with the random function on an Excel (Microsoft, Redmond, United States) file, stratified by sex and ODI scores (≤19: low; ≥20: high) in blocks of 4. Stratification was justified since gender systematically influences pain perception,24 and a high level of functional disability indicates a worse prognosis.17 The Excel file was password protected and accessible only by a researcher who was not involved in the participants’ assessments at baseline and at 6 weeks (CCP). The allocation sequence was completely hidden on the Excel until the next participant was assigned. AD enrolled participants but was blinded to the group allocation. CCP who was not involved in the evaluation and interventions – carried out concealed allocation, assigned participants to interventions group, and contacted the participant after the baseline evaluation to inform them on the location of the clinics to receive treatment. All participants of a group were treated in the same clinic where all patients received the same intervention (PIPT or usual physiotherapy) to limit contamination. Each physiotherapist only provided treatment for one of the groups and was not informed about the intervention provided in the other group.

Blinding

This was a single blinded study, where only the evaluator (AD) was blinded to participants’ allocation. Participants were instructed not to mention the intervention performed to the physiotherapist. Physiotherapists could not be blinded to the intervention they provided but they were blinded to the nature of the second study group and were not informed that only high-risk participants were recruited. These decisions were taken to limit the potential prescription of PIPT interventions in the UP group.

Data analysis

The analysis of the feasibility data is descriptive with mean and standard deviation or median and range depending on the outcomes. Success criteria for assessing feasibility are:

(i)

Recruitment of 30 participants and 6–8 physiotherapists; retention rate of participants of 80% at all follow-ups;

(ii)

Adherence to intervention: participants comply with 50% of the recommended interventions; physiotherapists in the PIPT group perform interventions addressing psychosocial factors in physiotherapy for more than 25% of clinical time, and those in the UP group, for less than 5%;

(iii)

Low risk of contamination objectified by the fact that no physiotherapist knows the nature of the other study group's intervention;

(iv)

Specific challenges must be considered modifiable to consider the pursuit of the project. Results will be compared to the success criteria to reach the conclusion that (1) a full study is not feasible, then, stop the project (i.e., do not pursue as a full clinical trial); (2) surmountable problems have been identified, so continue to a full study with modifications; (3) few major problems have been identified, but there are still unknowns, so a pilot study should be conducted; or (4) few major problems have been identified, so a full study can be conducted.47 For self-reported outcomes, an exploratory linear mixed models using Group and Time as fixed factors, participants’ intercept as a random factor, and age and sex as covariates, were used to determine the effect of the PIPT compared to UP on the SPSS software.2 An autoregressive covariance matrix was used and Sidak's corrections for multiple comparisons were applied. Mean and 95% confidence interval were reported.

Forty participants were recruited. Figure 1 presents the flow diagram.

Figure 1 Flow diagram.

DN4 = Douleur neuropathique 4 questionnaire; LBP = low back pain; STarTBack = STarT Back Screening Tool.

Sociodemographic variables and scores measured by self-reported questionnaires at baseline were compared between groups and presented in Table 2.

Table

Table 2 Sociodemographic Data

Table 2 Sociodemographic Data

PIPT group (n = 21) UP group (n = 19)
Age 35.8 (11.0) 33.1 (8.8)
Male, n (%) 12 (57.1) 10 (52.6)
LBP duration, n (%)
 3–5 months 0 (0) 2 (11)
 6–11 months 4 (19) 4 (21)
 1–5 years 10 (48) 3 (16)
 More than 5 years 7 (33) 10 (53)
Leg pain, n (%)
 Yes 8 (38) 7 (37)
 No 9 (43) 9 (47)
 Uncertain 4 (19) 3 (16)
Lumbar surgery, n (%)
Yes 2 (10) 1 (5)
No 19 (90) 18 (95)
Treatment used, n (%)
 Opioids 7 (33) 3 (16)
 Injection 5 (24) 4 (21)
 Exercise program 16 (76) 15 (79)
 Psychological support 2 (10) 2 (11)
Employment status, n (%)
 Student 4 (19) 8 (42)
 Unemployed 0 (0) 1 (5)
 Currently working part-time 1 (5) 1 (5)
 Currently working full time 13 (62) 8 (42)
 Retreat 1 (5) 0 (0)
 Disability due to LBP 1 (5) 1 (5)
 Disability for other reasons 1 (5) 0 (0)
Education level, n (%)
 Without high school diploma 1 (5) 0 (0)
 High school diploma 0 (0) 1 (5)
 Non-university certificate or diploma 3 (14) 4 (21)
 University diploma or degree below bachelor's degree 2 (10) 1 (5)
 Bachelor's degree 7 (33) 5 (26)
 Master's degree 6 (29) 7 (37)
 Doctorate 2 (10) 1 (5)
Pain intensity (average last 7 days) 5.0 (1.9) 5.7 (2.0)
Physical functioning 23.9 (11.8) 27.1 (12.2)
Kinesiophobia
 % above cut-off
25.9 (7.4)
10
28.7 (8.1)
21
Pain catastrophizing
 % above cut-off
18.3 (10.8)
19
25.7 (8.5)
37
Symptoms of central sensitization
 % above cut-off
17.6 (5.0)
29
20.7 (6.2)
53
Pain self-efficacy 7.6 (1.8) 7.2 (2.0)

*Data are presented as mean (SD) unless stated otherwise.

LBP = low back pain; PIPT = psychologically-informed physiotherapy; UP = usual physiotherapy.

Feasibility outcomes

Table 3 details the efficacy of recruitment strategies for participants and physiotherapists, the adherence to interventions, and the risk of contamination per group.

Table

Table 3 Efficacy of Recruitment Strategies, Adherence to Intervention, and Risk of Contamination Per Group

Table 3 Efficacy of Recruitment Strategies, Adherence to Intervention, and Risk of Contamination Per Group

Efficacy of recruitment strategies
For participants
Number of participants, n (%)
Assessed Eligible Recruited
Université Laval 242 (100) 42 (17) 30 (12)
CHU 5 (100) 3 (60) 3 (60)
List from the research team 13 (100) 3 (23) 3 (23)
Quebec Back Pain consortium 22 (100) 4 (18) 2 (9)
Social media 5 (100) 2 (40) 2 (40)
IRDPQ 4 (100) 0 (0) 0 (0)
For physiotherapists
Number of physiotherapists (n)
Contacted Recruited
PIPT group 8 5
UP group 11 5
Adherence to intervention
For participants
PIPT group UP group
Number of appointments completed per participant, median (min, max) 8 (6, 8) 8 (6, 8)
Self-reported adherence, mean (SD) 8.0 (1.0) 7.9 (1.2)
For physiotherapists
PIPT group UP group
Percentage of time addressing psychosocial factors on total time per treatment session, mean (SD) 6 (9) 38 (20)
Number of participants treated by physiotherapist, median (min, max) 3 (1, 8) 5 (1, 6)
Appointment time in minutes, mean (SD) 40.6 (5.6) 39.1 (3.7)
Risk of contamination
PIPT group UP group
Number of physiotherapists that have received information about the other study group, n 0 0

CHU = Centre d’expertise en Gestion de la Douleur Chronique du Centre Hospitalier Universitaire de Québec - Université Laval; IRDPQ = Institut de Réadaptation en Déficience Physique du Québec; max = maximum; min = minimum; PIPT = Psychologically-informed physiotherapy; SD = standard deviation; UP = usual physiotherapy.

Efficacy of the recruitment strategies

Participants were recruited between July 2021 and April 2022. The most effective recruitment source in terms of people assessed was mass emails sent to Laval University community (n = 242), and the least effective, the waiting list of the IRDPQ (n = 4). The most effective recruitment source in terms of percentage of eligible persons out of the total number of persons assessed was the waiting list of the CHU (60%), and the least effective, IRDPQ (0%). From the 40 participants recruited, 30 came from the Laval University's email lists, 3 from the CHU waiting list, 3 from the research team list, 2 from a Quebec Back Pain consortium mailing list, and 2 from social media. For physiotherapists, 19 physiotherapists were contacted and 10 were recruited.

Adherence to intervention

No difference was observed between groups for the number of appointment (PIPT/UP: 8 (6, 8)), the participants’ self-reported adherence to intervention (PIPT: 8.0 (1.0); UP: 7.9 (1.2)), number of participants treated per physiotherapist (PIPT: 3 (1, 8); UP: 5 (1, 6)), and time per appointment (PIPT: 40.6 (5.6); UP: 39.1 (3.7)). There was a between-group difference between the time addressing psychosocial factors (PIPT: 38 (20)%; UP: 6 (9)%).

Risk of contamination and specific challenges

Physiotherapists from the UP (n = 3) and PIPT (n = 3) groups completed a 20-minutes semi-structured interview. None reported having been informed about the other study group. For the specific challenges encountered, physiotherapists named the presence of complex cases requiring multidisciplinary management (n = 3), participants’ adherence to the prescribed interventions (n = 3), the absence of a procedure to follow when a patient was in COVID isolation (n = 2), the appropriateness of adding a follow-up to the experimental training during data collection (n = 2), and technological difficulties with RedCap to complete the checklist (n = 1).

Self-reported outcomes

Figure 2 reports the evolution of scores pertaining to each self-reported questionnaire at all timepoints (mean and 95% confidence intervals). Supplementary Table 1 presents mean differences and 95% confidence intervals between the baseline and other time points for both groups. Exploratory analyses suggest that most outcomes improved over time except for quality of life (mental) and self-efficacy for which the 95% confidence intervals include 0 (Figure 2 and Supplementary Table 1). Supplementary Table 2 reports between-group comparisons and 95% confidence interval differences at all time points. For between-group difference, 95% confidence intervals did include 0 for all outcomes except for pain catastrophizing at baseline and when all time points were considered together (main effect of Group – Supplementary Table 2). Overall, results suggest improvement over time for most self-reported outcomes without between-group differences at follow-ups.

Figure 2 Mean scores (95% confidence interval) per group at baseline, 6, 12, and 24 weeks for physical functioning (A), pain (B), kinesiophobia (C), catastrophizing (D), physical quality of life (E), mental quality of life (F), symptoms of central sensitization (G), and self-efficacy (H).

The dotted lines represent the cut-off determining the present of a construct for some questionnaires. Shaded area represents the 95% confidence intervals (blue: usual physiotherapy; red: psychologically-informed physiotherapy; purple: overlap between confidence intervals). CSI = Central Sensitization Inventory; CPSES = Chronic Pain Self-Efficacy Scale; NRS = Numeric Rating Scale; ODI = Oswestry Disability Index; PCS = Pain Catastrophizing Scale; PIPT = psychologically informed physiotherapy; TSK = Tampa scale of Kinesiophobia; UP = usual physiotherapy.
Perception of change

At 6 weeks, negative (i.e., score −5, −4, −3, or −2), neutral (i.e., score −1, 0, or 1), and positive (i.e., score 2, 3, 4, or 5) general perceptions of change were shared by 0%, 33%, and 67% of participants in the control group, compared with 0%, 20%, and 80% in the experimental group, respectively. Negative, neutral, and positive perceptions of change regarding pain medication were shared by 0%, 60%, and 40% of participants in both groups.

The primary objective of this study was to determine the feasibility of a RCT testing the efficacy of a PIPT intervention in people with CLBP at high risk of poor prognosis according to the Start Back screening tool, compared with UP. The secondary objective was to explore the effects of the interventions on clinical variables. Most of the success criteria stated in the objectives have been met. First, the various recruitment strategies allowed the recruitment of 40 participants in 9 months, and 10 physiotherapists participated in the study. However, retention of participants at 6 months is less than 80%. Second, the adherence to the intervention was very good for both participants and physiotherapists. Third, the study set-up permitted to avoid contamination between sites using two different clinical sites each providing different interventions. Fourth, the specific challenges that were identified are easily modifiable. Finally, the exploratory analyses of self-reported outcomes showed small between-group differences, unlikely to be clinically meaningful, although an improvement over time was reported for most outcomes measured for both groups. Therefore, the results support the feasibility of a fully powered randomized controlled trial (RCT), with modifications to the current protocol, to test the efficacy of PIPT in private physiotherapy clinics, although it is unlikely that a the future RCT will permit to detect clinically meaningful differences between groups.

Limitations and challenges

Although conducting a full RCT seems feasible, some limitations should be considered. Firstly, the attrition rate at 6-month follow-up (including withdrawals) was 21% (UP) and 33% (PIPT), which is above the commonly accepted 20% in RCTs.49 The present results should be interpreted with caution, based on this limitation. Future studies may mitigate this issue,50 for instance, by minimizing inconvenience for the participant (e.g., in terms of travel, time required), by convincing the participants of the importance of the project, by reducing the intervals between follow-ups or by adding financial incentives at follow-ups. Secondly, although our recruitment strategies were adequate to recruit participants corresponding to the eligibility criteria, 95% of the sample had a post-secondary diploma. This is higher than the general population in the province of Quebec (62.6% women and 51.5% men in 2021).24 This may affect the generalizability of the present findings and highlights the difficulty to recruit patients with lower educational level in research protocols.51 The recruitment of participants with a higher level of education is expected considering the efficacy of the recruitment using Laval University email lists compared to other recruitment strategies. The recruitment of patients in pain clinics’ waiting lists could have improved the representativeness of the sample. However, only a few potential participants met the eligibility criteria or were interested in participating. Adding other recruitment strategies such as using social media or recruitment via 3rd party payers, public insurers or through workers’ compensation system could improve the representativeness of the recruited sample in future studies.24 Also, considering the significant number of participants excluded due to the presence of neuropathic pain, it is relevant to consider removing this exclusion criterion which is often present in high-risk patients. By doing so, we not only ensure better representation of the high-risk population but also facilitate the recruitment process. Regarding specific challenges, consideration should be given to the implementation of a case management protocol for COVID or other infectious diseases. For example, continuation of the treatment plan in telerehabilitation would limit dropouts. Another specific challenge was the presence of technological difficulties when physiotherapists completed the checklists on RedCap. Thus, it seems important to offer to complete the checklist electronically or on paper, at the physiotherapist's convenience, to facilitate the implementation of the research project. Although participant adherence to the interventions was named as a specific challenge by the physiotherapists, participants reported that they adhered very well to the proposed treatment plan. This discrepancy between participants and physiotherapists could be resolved by using a logbook to measure day-to-day adherence to treatment and strategies to promote the adherence to the interventions (e.g., telephone reminder). For a future RCT, it would be possible to include participants identified as being at moderate risk. This would facilitate recruitment and increase the study's external validity, although psychologically-informed physiotherapy is recommended only for the high-risk group while evidence-based physiotherapy is recommended for the medium-risk group.18

Comparison with literature

As this is a pilot and feasibility RCT, it is not possible to conclude on the effectiveness (or non-effectiveness) of the interventions. Although statistical analyses were performed, it remains exploratory, and the absence of differences cannot be interpreted due to the lack of power. Results from other studies should be compared with caution. Nonetheless, considering that none of the between-group differences for pain and physical functioning exceeded minimal clinically important differences (2 pts for pain,52 and 10% for ODI,53 respectively), it suggests that the differences between interventions are not clinically meaningful. For the high-risk subgroup, some clinical trials compared usual care and PIPT and reported between-group differences of 2.53 (95% CI 0.90, 4.16) in favour of PIPT at 4 months,18 0.60 (95% CI 2.48, −1.27) in favour of PIPT at 6 months,20 on the Roland-Morris Disability Questionnaire (RMDQ), and 2.1 (95%CI 4.9, −0.6) in favour of PIPT at 6 months,21 on the ODI. Considering the minimum clinically significant differences (RMDQ: 3.5 pts; ODI: 10%),53 the size of the effects, when present, was small. In comparison, a between-group difference of approximately 5.54 in favour of PIPT on the ODI at 6 weeks was observed in the present study. For pain intensity, between-group differences in published clinical trials were 0.73 (95% CI 0.04, 1.42) in favour of PIPT at 4 months,18 and 0.002 (95% CI −0.79, 0.79) at 6 months.20 In comparison, we observed a between-group difference of approximately 0.78 in favour of PIPT at 6 weeks. Similarly, between-group differences for pain, if present, were also small.

Different factors may explain the discrepancies with published studies from the Keele's group.18,19 One could argue that the PIPT intervention may have not been different enough from the UP intervention. Based on our results, it is unlikely since the PIPT intervention devoted much more time using specific psychosocial interventions than the UP intervention. Another possibility is that physiotherapists were not proficient at providing the PIPT intervention because of limited training or lack of experience. Depending on studies, training duration for physiotherapists in PIPT varies from 1 day,54 5 days,20 and up to 6 days,18 with teaching modalities varying from primarily didactic to a combination of didactic and experiential with feedback. It is possible that the 2-day training was not sufficient, although optimal training parameters, in terms of duration, intensity, and preferred modalities remain unknown.15 Follow-up training, for example, adding an extra day of training a month after the completion of the 2-day training, or even extending the training duration may be necessary to optimize the effects of PIPT. Moreover, the 25% threshold (time requested to mitigate psychosocial factors in PIPT) was determined subjectively, based on the team's clinical expertise, the available literature on the subject, and participants’ likely expectations during a physiotherapy consultation. The study of different thresholds in relation to the effectiveness of interventions is highly relevant and need to be further explored.

The small between-group differences may be explained by the sample characteristics. For example, the recruited sample presented some favorable prognostic factors. Indeed, even though patients were identified as being at high risk of poor prognosis due to the significant presence of psychosocial factors contributing to their pain by the STarT Back Screening Tool,11 they presented high level of self-efficacy, positive expectations to resolve their pain using the proposed interventions, and, as previously discussed, high educational level considered as positively influencing the prognosis.55,56 In addition, only a minority of participants showed high levels of kinesiophobia, that is, 21% and 10%, and pain catastrophizing, that is, 37% and 19% of participants in the UP and PIPT groups, respectively, according to the cut-offs of specific questionnaires. The ability of the STarT Back Screening Tool to identify CLBP patients with high level of psychosocial factors may be lower when recruitment is not limited to primary care health centers.57 Nonetheless, it is important to mention that physiotherapists considered that many cases were complex and would have required multidisciplinary interventions. Overall, the recruited participants had mixed clinical profiles of favorable and unfavorable prognostic factors that may have influenced responses to interventions.

The feasibility of a RCT evaluating the effectiveness of PIPT is supported by acceptable recruitment of participants and physiotherapists, good adherence of participants and physiotherapists to the interventions, low risk of contamination between sites and specific challenges that may be addressed. Some issues have been highlighted, including the representativeness of the sample and attrition. Preliminary data suggest improvement over time for functional capacity, pain, physical quality of life, kinesiophobia, pain catastrophizing, and central sensitization for both groups.

What is already known on this topic

Psychologically-informed physiotherapy appears to be more effective than standard physical therapy in individuals at high risk for poor prognosis. However, significant implementation problems have been encountered in implementing this approach in the United States.

What this study adds

A randomized clinical trial evaluating the efficacy of psychologically-informed physiotherapy compared to usual physiotherapy is feasible with slight modifications but seems not superior to usual physiotherapy.

Hugo Massé-Alarie is an associate professor at the School of Rehabilitation Sciences, Université Laval, Quebec. He is a physical therapist with expertise in the neural control of trunk muscles in health and diseases, especially low back pain. His research is divided into three complementary main themes: (i) to improve the understanding of the neural control of trunk muscles using neurophysiology and neuroimaging techniques; (ii) to determine the impact of low back pain on the neural control of trunk muscles and of movement on pain, (iii) to optimise the management of low back pain, especially by focussing on the use of non-invasive and non-surgical interventions such as physical therapy, exercises, and neurostimulation.

Notes

1 REDCap (Research Electronic Data Capture), 1211 Medical Center Drive, Nashville, Tennesee, 37232.

2 IBM Corp. Released 2021. IBM SPSS Statistics for Macintosh, Version 29.0. Armonk, NY: IBM Corp.

1. Dionne CE, Dunn KM, Croft PR, et al. A consensus approach toward the standardization of back pain definitions for use in prevalence studies. Spine (Phila Pa 1976). 2008;33(1):95103. https://doi.org/10.1097/BRS.0b013e31815e7f94. PMID: 18165754 Google Scholar
2. Maher C, Underwood M, Buchbinder R. Non-specific low back pain. Lancet. 2017;389(10070):73647. https://doi.org/10.1016/S0140-6736(16)30970-9. PMID: 27745712 Google Scholar
3. Rozenberg S. [Chronic low back pain: definition and treatment]. Rev Prat. 2008;58(3):26572. PMID: 18536200 Lombalgie chronique, définition et prise en charge. Google Scholar
4. Meucci RD, Fassa AG, Faria NM. Prevalence of chronic low back pain: systematic review. Rev Saude Publica. 2015;49:1. https://doi.org/10.1590/s0034-8910.2015049005874. PMID: 26487293 Google Scholar
5. GBD 2017 Disease and Injury Incidence and Prevalence Collaborators. Global, regional, and national incidence, prevalence, and years lived with disability for 354 diseases and injuries for 195 countries and territories, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017. Lancet. 2018;392(10159):1789858. https://doi.org/10.1016/s0140-6736(18)32279-7. PMID: 30496104 Google Scholar
6. Saragiotto BT, Maher CG, Yamato TP, et al. Motor control exercise for chronic non-specific low-back pain. Cochrane Database Syst Rev. 2016; 1):Cd012004. https://doi.org/10.1002/14651858.Cd012004. PMID: 26742533 Google Scholar
7. Fernández-Rodríguez R, Álvarez-Bueno C, Cavero-Redondo I, et al. Best exercise options for reducing pain and disability in adults with chronic low back pain: pilates, strength, core-based, and mind-body. A network meta-analysis. J Orthop Sports Phys Ther. 2022;52(8):50521. https://doi.org/10.2519/jospt.2022.10671. PMID: 35722759 Google Scholar
8. Clarke CL, Ryan CG, Martin DJ. Pain neurophysiology education for the management of individuals with chronic low back pain: systematic review and meta-analysis. Man Ther. 2011;16(6):5449. https://doi.org/10.1016/j.math.2011.05.003. PMID: 21705261 Google Scholar
9. Hartvigsen J, Hancock MJ, Kongsted A, et al. What low back pain is and why we need to pay attention. Lancet. 2018;391(10137):235667. https://doi.org/10.1016/S0140-6736(18)30480-X. PMID: 29573870 Google Scholar
10. Foster NE, Hill JC, O'Sullivan P, Hancock M. Stratified models of care. Best Pract Res Clin Rheumatol. 2013;27(5):64961. https://doi.org/10.1016/j.berh.2013.10.005. PMID: 24315146 Google Scholar
11. Traeger A, McAuley JH. STarT back screening tool. J Physiother. 2013;59(2):131. https://doi.org/10.1016/s1836-9553(13)70170-x. PMID: 23663803 Google Scholar
12. Hill JC, Dunn KM, Lewis M, et al. A primary care back pain screening tool: identifying patient subgroups for initial treatment. Arthritis Rheum. 2008;59(5):63241. https://doi.org/10.1002/art.23563. PMID: 18438893 Google Scholar
13. Hay EM, Dunn KM, Hill JC, et al. A randomised clinical trial of subgrouping and targeted treatment for low back pain compared with best current care. The STarT Back Trial Study Protocol. BMC Musculoskelet Disord. 2008;9(2008):58. https://doi.org/10.1186/1471-2474-9-58. PMID: 18430242 Google Scholar
14. Main CJ, George SZ. Psychologically informed practice for management of low back pain: future directions in practice and research. Phys Ther. 2011;91(5):8204. https://doi.org/10.2522/ptj.20110060. PMID: 21451091 Google Scholar
15. Ballengee LA, Zullig LL, George SZ. Implementation of psychologically informed physical therapy for low back pain: where do we stand, where do we go? J Pain Res. 2021;14:374757. https://doi.org/10.2147/jpr.S311973. PMID: 34908873 Google Scholar
16. Foster NE, Anema JR, Cherkin D, et al. Prevention and treatment of low back pain: evidence, challenges, and promising directions. Lancet. 2018;391(10137):236883. https://doi.org/10.1016/S0140-6736(18)30489-6. PMID: 29573872 Google Scholar
17. Chou R, Shekelle P. Will this patient develop persistent disabling low back pain? Jama. 2010;303(13):1295302. https://doi.org/10.1001/jama.2010.344 Google Scholar
18. Hill JC, Whitehurst DG, Lewis M, et al. Comparison of stratified primary care management for low back pain with current best practice (STarT Back): a randomised controlled trial. Lancet. 2011;378(9802):156071. https://doi.org/10.1016/s0140-6736(11)60937-9. PMID: 21963002 Google Scholar
19. Foster NE, Mullis R, Hill JC, et al. Effect of stratified care for low back pain in family practice (IMPaCT Back): a prospective population-based sequential comparison. Ann Fam Med. 2014;12(2):10211. https://doi.org/10.1370/afm.1625. PMID: 24615305 Google Scholar
20. Cherkin D, Balderson B, Wellman R, et al. Effect of low back pain risk-stratification strategy on patient outcomes and care processes: the MATCH randomized trial in primary care. J Gen Intern Med. 2018;33(8):132436. https://doi.org/10.1007/s11606-018-4468-9. PMID: 29790073 Google Scholar
21. Delitto A, Patterson CG, Stevans JM, et al. Stratified care to prevent chronic low back pain in high-risk patients: the TARGET trial. A multi-site pragmatic cluster randomized trial. EClinicalMedicine. 2021;34:100795. https://doi.org/10.1016/j.eclinm.2021.100795. PMID: 33870150 Google Scholar
22. Eldridge SM, Chan CL, Campbell MJ, et al. CONSORT 2010 statement: extension to randomised pilot and feasibility trials. BMJ. 2016;355:i5239. https://doi.org/10.1136/bmj.i5239. PMID: 27777223 Google Scholar
23. Harris PA, Taylor R, Thielke R, Payne J, Gonzalez N, Conde JG. Research electronic data capture (REDCap)--a metadata-driven methodology and workflow process for providing translational research informatics support. J Biomed Inform. 2009;42(2):37781. https://doi.org/10.1016/j.jbi.2008.08.010. PMID: 18929686 Google Scholar
24. Pagé GM, Lacasse A, Beaudet N, et al. The Quebec Low Back Pain Study: a protocol for an innovative 2-tier provincial cohort. Pain Rep. 2020;5(1):e799. https://doi.org/doi:10.1097/pr9.0000000000000799. Google Scholar
25. Bouhassira D, Attal N, Alchaar H, et al. Comparison of pain syndromes associated with nervous or somatic lesions and development of a new neuropathic pain diagnostic questionnaire (DN4). Pain. 2005;114(1–2):2936. https://doi.org/10.1016/j.pain.2004.12.010. PMID: 15733628 Google Scholar
26. Lacasse A, Roy JS, Parent AJ, et al. The Canadian minimum dataset for chronic low back pain research: a cross-cultural adaptation of the National Institutes of Health Task Force Research Standards. CMAJ Open. 2017;5(1):E23748. https://doi.org/10.9778/cmajo.20160117. PMID: 28401140 Google Scholar
27. Deyo RA, Dworkin SF, Amtmann D, et al. Report of the NIH task force on research standards for chronic low back pain. Spine (Phila Pa 1976). 2014;39(14):112843. https://doi.org/10.1097/brs.0000000000000434. PMID: 24887571 Google Scholar
28. Lochman JE, Baden RE, Boxmeyer CL, et al. Does a booster intervention augment the preventive effects of an abbreviated version of the coping power program for aggressive children? J Abnorm Child Psychol. 2014;42(3):36781. https://doi.org/10.1007/s10802-013-9727-y. PMID: 23417235 Google Scholar
29. National Institute for Health and Care Excellence. Low back pain and Sciatica in over 16s: assessment and management. UK: National Institute for Health and Care Excellence; 2020. Copyright © NICE, 2016. Google Scholar
30. Stochkendahl MJ, Kjaer P, Hartvigsen J, et al. National Clinical Guidelines for non-surgical treatment of patients with recent onset low back pain or lumbar radiculopathy. Eur Spine J. 2018;27(1):6075. https://doi.org/10.1007/s00586-017-5099-2. PMID: 28429142 Google Scholar
31. Delitto A, George SZ, Van Dillen L, et al. Low back pain. J Orthop Sports Phys Ther. 2012;42(4):A157. https://doi.org/10.2519/jospt.2012.42.4.A1. PMID: 22466247 Google Scholar
32. Qaseem A, Wilt TJ, McLean RM, Forciea MA, Clinical Guidelines Committee of the American College of P. Noninvasive treatments for acute, subacute, and chronic low back pain: a clinical practice guideline from the American College of Physicians. Ann Intern Med. 2017;166(7):51430. https://doi.org/10.7326/M16-2367. PMID: 28192789. Google Scholar
33. Toward Optimized Practice (TOP) Low Back Pain Working Group. Evidence-informed primary care management of low back pain: clinical practice guideline. https://portal.cfpc.ca/resourcesdocs/uploadedFiles/Directories/Committees_List/Low_Back_Pain_Guidelines_Oct19.pdf. Google Scholar
34. Chiarotto A, Boers M, Deyo RA, et al. Core outcome measurement instruments for clinical trials in nonspecific low back pain. Pain. 2018;159(3):48195. https://doi.org/10.1097/j.pain.0000000000001117. PMID: 29194127 Google Scholar
35. Chimenti RL, Post AA, Silbernagel KG, et al. Kinesiophobia severity categories and clinically meaningful symptom change in persons with achilles tendinopathy in a cross-sectional study: implications for assessment and willingness to exercise. Front Pain Res (Lausanne). 2021;2:739051. https://doi.org/10.3389/fpain.2021.739051. PMID: 35295417 Google Scholar
36. Franchignoni F, Giordano A, Ferriero G, Monticone M. Measurement precision of the Pain Catastrophizing Scale and its short forms in chronic low back pain. Sci Rep. 2022;12(1):12042. https://doi.org/10.1038/s41598-022-15522-x. PMID: 35835830 Google Scholar
37. Tanaka K, Nishigami T, Mibu A, et al. Cutoff value for short form of central sensitization inventory. Pain Pract. 2020;20(3):26976. https://doi.org/10.1111/papr.12850. PMID: 31638741 Google Scholar
38. Chapman JR, Norvell DC, Hermsmeyer JT, et al. Evaluating common outcomes for measuring treatment success for chronic low back pain. Spine (Phila Pa 1976). 2011;36(21 Suppl):S5468. https://doi.org/10.1097/BRS.0b013e31822ef74d. PMID: 21952190 Google Scholar
39. Hawker GA, Mian S, Kendzerska T, French M. Measures of adult pain: Visual Analog Scale for Pain (VAS Pain), Numeric Rating Scale for Pain (NRS Pain), McGill Pain Questionnaire (MPQ), Short-Form McGill Pain Questionnaire (SF-MPQ), Chronic Pain Grade Scale (CPGS), Short Form-36 Bodily Pain Scale (SF-36 BPS), and Measure of Intermittent and Constant Osteoarthritis Pain (ICOAP). Arthritis Care Res (Hoboken). 2011;63(Suppl 11):S24052. https://doi.org/10.1002/acr.20543. PMID: 22588748 Google Scholar
40. Maughan EF, Lewis JS. Outcome measures in chronic low back pain. Eur Spine J Sep. 2010;19(9):148494. https://doi.org/10.1007/s00586-010-1353-6. PMID: 20397032 Google Scholar
41. Luo X, George ML, Kakouras I, et al. Reliability, validity, and responsiveness of the short form 12-item survey (SF-12) in patients with back pain. Spine (Phila Pa 1976). 2003;28(15):173945. https://doi.org/10.1097/01.Brs.0000083169.58671.96. PMID: 12897502 Google Scholar
42. Woby SR, Roach NK, Urmston M, Watson PJ. Psychometric properties of the TSK-11: a shortened version of the Tampa Scale for Kinesiophobia. Pain. 2005;117(1–2):13744. https://doi.org/10.1016/j.pain.2005.05.029. PMID: 16055269 Google Scholar
43. Osman A, Barrios FX, Kopper BA, Hauptmann W, Jones J, O’Neill E. Factor structure, reliability, and validity of the Pain Catastrophizing Scale. J Behav Med. 1997;20(6):589605. https://doi.org/10.1023/a:1025570508954. PMID: 9429990 Google Scholar
44. Scerbo T, Colasurdo J, Dunn S, Unger J, Nijs J, Cook C. Measurement properties of the central sensitization inventory: a systematic review. Pain Pract. 2018;18(4):54454. https://doi.org/10.1111/papr.12636. PMID: 28851012 Google Scholar
45. Lacasse A, Bourgault P, Tousignant-Laflamme Y, Courtemanche-Harel R, Choinière M. Development and validation of the French-Canadian Chronic Pain Self-efficacy Scale. Pain Res Manag. 2015;20(2):7583. https://doi.org/10.1155/2015/832875. PMID: 25848845 Google Scholar
46. Kamper SJ, Maher CG, Mackay G. Global rating of change scales: a review of strengths and weaknesses and considerations for design. J Man Manip Ther. 2009;17(3):16370. https://doi.org/10.1179/jmt.2009.17.3.163. PMID: 20046623 Google Scholar
47. Abbott JH. The distinction between randomized clinical trials (RCTs) and preliminary feasibility and pilot studies: what they are and are not. J Orthop Sports Phys Ther. 2014;44(8):5558. https://doi.org/10.2519/jospt.2014.0110. PMID: 25082389 Google Scholar
48. Hertzog MA. Considerations in determining sample size for pilot studies. Res Nurs Health. 2008;31(2):18091. https://doi.org/10.1002/nur.20247. PMID: 18183564 Google Scholar
49. Fewtrell MS, Kennedy K, Singhal A, et al. How much loss to follow-up is acceptable in long-term randomised trials and prospective studies? Arch Dis Child. 2008;93(6):45861. https://doi.org/10.1136/adc.2007.127316. PMID: 18495909 Google Scholar
50. Cutler RB, Fishbain DA, Cole B, Steele-Rosomoff R, Rosomoff HL. Identifying patients at risk for loss to follow-up after pain center treatment. Pain Med. 2001;2(1):4651. https://doi.org/10.1046/j.1526-4637.2001.002001046.x. PMID: 15102317 Google Scholar
51. Kripalani S, Goggins K, Couey C, et al. Disparities in research participation by level of health literacy. Mayo Clin Proc. 2021;96(2):31421. https://doi.org/10.1016/j.mayocp.2020.06.058. PMID: 33549253 Google Scholar
52. Chiarotto A, Maxwell LJ, Ostelo RW, Boers M, Tugwell P, Terwee CB. Measurement properties of visual analogue scale, numeric rating scale, and pain severity subscale of the brief pain inventory in patients with low back pain: a systematic review. J Pain. 2019;20(3):24563. https://doi.org/10.1016/j.jpain.2018.07.009. PMID: 30099210 Google Scholar
53. Ostelo RW, de Vet HC. Clinically important outcomes in low back pain. Best Pract Res Clin Rheumatol. 2005;19(4):593607. https://doi.org/10.1016/j.berh.2005.03.003. PMID: 15949778 Google Scholar
54. Beneciuk JM, George SZ, Greco CM, et al. Targeted interventions to prevent transitioning from acute to chronic low back pain in high-risk patients: development and delivery of a pragmatic training course of psychologically informed physical therapy for the TARGET trial. Trials. 2019;20(1):256. https://doi.org/10.1186/s13063-019-3350-3. PMID: 31060589 Google Scholar
55. Hartvigsen J, Hancock MJ, Kongsted A, et al. What low back pain is and why we need to pay attention. Lancet. 2018;391(10137):235667. https://doi.org/10.1016/s0140-6736(18)30480-x. PMID: 29573870 Google Scholar
56. Hayden JA, Wilson MN, Riley RD, Iles R, Pincus T, Ogilvie R. Individual recovery expectations and prognosis of outcomes in non-specific low back pain: prognostic factor review. Cochrane Database Syst Rev. 2019;2019(11):CD011284. https://doi.org/10.1002/14651858.CD011284.pub2. PMID: 31765487 Google Scholar
57. Beneciuk JM, Bishop MD, Fritz JM, et al. The STarT back screening tool and individual psychological measures: evaluation of prognostic capabilities for low back pain clinical outcomes in outpatient physical therapy settings. Phys Ther. 2013;93(3):32133. https://doi.org/10.2522/ptj.20120207. PMID: 23125279 Google Scholar