The Quebec Low Back Pain Study: a protocol for an innovative 2-tier provincial cohort

Trajectories of pain and depressive symptoms among people living with low back pain during the COVID-19 pandemic: a 24-month longitudinal study

Introduction: We explored trajectories of pain intensity and depressive symptoms over the first 24 months of the pandemic in people with low back pain. Methods: This longitudinal study was conducted alongside the Quebec Low Back Pain Study. Starting in April 2020 and every 3 months until July 2022, 291 participants completed an online survey. Group-based trajectory modeling was used to identify patterns of pain intensity and depressive symptoms. Onset outbreak characteristics were then put in relation with trajectory groups using multivariate logistic regression. Results: The analysis revealed 5 trajectories of pain intensity and depressive symptoms, respectively. The pain trajectories were stable mild (n = 17, 5.8%); stable moderate (n = 103, 35.4%); stable severe (n = 81, 27.8%); U-shape (n = 24, 8.3%), and inverted U-shape (n = 66, 22.7%). The trajectories of depressive symptoms were stable none (n = 58, 19.9%); stable very mild (n = 61, 21.0%); stable mild (n = 85, 29.2%); stable moderate (n = 59, 21.7%); and severe slightly improving (n = 24, 8.3%). Pre-COVID everyday/nearly everyday pain, average pain intensity, and widespread bodily pain were predictive of pain trajectory groups. Higher pre-COVID depression, acute stress disorder, and lockdown measures-related stress were associated with moderate/severe depressive trajectories. Discussion: Our findings indicated relative stability of pain and depressive symptoms among participants during the COVID-19 pandemic but also highlighted subgroups of people who experienced temporary deterioration or improvement over the first months of the pandemic that then reverted back to baseline levels. Modifiable risk factors were identified before the onset of the pandemic, which could give preventive measures in targeted populations.

Efficacy of a Psychologically-Informed Physiotherapy Intervention in Patients with Chronic Low Back Pain at High Risk of Poor Prognosis: A Pilot and Feasibility Randomized Controlled Trial

Purpose

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.

Method

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.

Results

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.

Conclusions

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.

The Effects of Combined Motor Control and Isolated Extensor Strengthening versus General Exercise on Paraspinal Muscle Morphology, Composition, and Function in Patients with Chronic Low Back Pain: A Randomized Controlled Trial

Low back pain (LBP), a globally widespread and persistent musculoskeletal disorder, benefits from exercise therapy. However, it remains unclear which type leads to greater changes in paraspinal muscle health. This study aimed to (1) compare the effects of a combined motor control and isolated lumbar extension exercise (MC+ILEX) versus a general exercise (GE) intervention on paraspinal muscle morphology, composition, and function, and (2) examine whether alterations in paraspinal muscle health were correlated with improvements in pain, function, and quality of life. Fifty participants with chronic LBP were randomly assigned to each group and underwent a 12-week supervised intervention program. Magnetic resonance imaging and ultrasound assessments were acquired at baseline, 6 and 12 weeks to examine the impact of each intervention on erector spinae (ES) and multifidus (MF) muscle size (cross-sectional area, CSA), composition, and function at L4-L5 and L5-S1. Self-reported questionnaires were also acquired to assess participant-oriented outcomes. Our findings indicated that the MC+ILEX group demonstrated greater improvements in MF and ES CSA, along with MF thickness at both levels (all p < 0.01). Both groups significantly improved in pain, function, and quality of life. This study provided preliminary results suggesting that an MC+ILEX intervention may improve paraspinal morphology while decreasing pain and disability.

Understanding the pain experience of lionfish envenomation

Introduction

Stings from the lionfish (Pterois volitans) constitute one of the most painful wounds in the ocean. This species has invaded the Atlantic coast of the United States, Gulf of Mexico, Caribbean, and Mediterranean Sea. In addition to its ecological impact on local fish populations, stings from the lionfish pose a medical problem because of the debilitating nature of the pain they produce. However, there are no studies examining the human pain experience of lionfish stings.

Objective

To characterize the various aspects of the pain experience following a lionfish sting.

Methods

We developed a pain questionnaire that includes validated scales used with patients having acute or chronic pain to understand the pain variability, as well as the use of health care resources and treatments.

Results

We provide the first study of the pain experience from lionfish stings. Here, we show that the pain is intense from the start and peaks approximately 1 hour later, resolving itself in 7 days for most victims. Furthermore, pain intensity can be influenced by several factors, including (1) age of the victim, where older victims experience significantly higher pain intensities, (2) the number of spines involved, (3) and whether infection occurred at the injury site. However, pain intensity was not different between male and female participants.

Conclusion

These findings will inform the medical community on the pain experience and can be used by local authorities to better appreciate the impact of lionfish envenomations to develop programs aimed at curtailing the expansion of the lionfish.

Within-Session Test-Retest Reliability of Pressure Pain Threshold and Mechanical Temporal Summation in Chronic Low Back Pain

OBJECTIVES

To determine the absolute and relative within-session test-retest reliability of pressure pain threshold (PPT) and temporal summation of pain (TSP) at the low back and the forearm in individuals with chronic low back pain (CLBP) and to test the impact of different sequences of measurements on reliability metrics.

MATERIALS AND METHODS

Twenty-eight adults with CLBP were recruited. Relative (intraclass correlation coefficient [ICC] and coefficient of variation) and absolute reliability (standard error of measurement and minimal detectable changes) were quantified at 4 sites (back: sacrum and lumbar erector spinae; wrist: hand dorsum and wrist flexors) for PPT and 2 sites (hand and low back) for TSP, for various sequences of measurements.

RESULTS

Systematic differences were found between within test and retest for most PPT sequences at the lumbar erector spinae site and 1 TSP sequence (1-2-3) at back and hand sites, precluding reliability analyses for these data. Within-session PPT relative reliability was excellent at low back (ICC = 0.83 to 0.94) and wrist (ICC = 0.88 to 0.97) sites, whereas TSP showed good to excellent reliability at hand (ICC = 0.80 to 0.90) and low back (ICC = 0.73 to 0.89). In general, 2 and 3 measurements optimized absolute and relative reliability for TSP and PPT, respectively.

DISCUSSION

Within-session reliability was generally excellent for PPT and TSP at the low back and hand sites among individuals with CLBP. We recommend using 3 measurements for PPT and 2 for TSP to optimize reliability. Caution is recommended when testing PPT of the painful lower back area since a systematic difference was present between the test and retest.

Assessment of exercise-induced hypoalgesia in chronic low back pain and potential associations with psychological factors and central sensitization symptoms: A case-control study

INTRODUCTION

Exercise is the most recommended treatment for chronic low back pain (CLBP) and is effective in reducing pain, but the mechanisms underlying its effects remain poorly understood. Exercise-induced hypoalgesia (EIH) may play a role and is thought to be driven by central pain modulation mechanisms. However, EIH appears to be disrupted in many chronic pain conditions and its presence in people with CLBP remains unclear. As people suffering from chronic pain often exhibit psychological factors and central sensitization symptoms influencing pain perception, EIH might be associated with these factors.

OBJECTIVE

The aim of this study is to compare the level of EIH between participants with and without CLBP following back and wrist exercises and to assess the associations between EIH, psychological factors, and symptoms of central sensitization (using the central sensitization inventory - CSI) in CLBP.

METHOD

Twenty-eight participants with CLBP and 23 without pain were recruited. Pressure pain thresholds (PPT) were measured at 4 sites (2 bony sites = capitate, S1|2 muscle sites = wrist flexors, lumbar erector spinae) before and after each of two exercises (wrist flexion and lumbar extension). Exercise-induced hypoalgesia was defined as percent change in PPT from pre- to post-exercise. Participants with CLBP also completed questionnaires to measure psychological factors (e.g., kinesiophobia, catastrophizing, anxiety, and self-efficacy) and symptoms of central sensitization (CSI), and correlations with EIH were calculated.

RESULTS

After wrist exercise, EIH measured at the muscle sites was lower in the CLBP group compared with the pain-free group (p = 0.047) but no differences were found at bony sites (p = 0.49). No significant differences for EIH were observed following back exercise at muscle sites (p = 0.14) or at bony sites (p = 0.65). Exercise-induced hypoalgesia was not correlated with any psychological factors or with the CSI score.

CONCLUSION

The lower EIH following wrist exercises may represent an alteration in pain modulation control in CLBP. However, psychological factors and central sensitization symptoms may not explain the differences observed.

The Canadian version of the National Institutes of Health minimum dataset for chronic low back pain research: reference values from the Quebec Low Back Pain Study

ABSTRACT

The National Institutes of Health (NIH) minimum dataset for chronic low back pain (CLBP) was developed in response to the challenge of standardizing measurements across studies. Although reference values are critical in research on CLBP to identify individuals and communities at risk of poor outcomes such as disability, no reference values have been published for the Quebec (Canada) context. This study was aimed to (1) provide reference values for the Canadian version of the NIH minimum dataset among individuals with CLBP in Quebec, both overall and stratified by gender, age, and pain impact stratification (PIS) subgroups, and (2) assess the internal consistency of the minimum data set domains (pain interference, physical function, emotional distress or depression, sleep disturbance, and PIS score). We included 2847 individuals living with CLBP who completed the baseline web survey of the Quebec Low Back Pain Study (age: 44.0 ± 11.2 years, 48.1% women) and were recruited through social media and healthcare settings. The mean score was 6.1 ± 1.8 for pain intensity. Pain interference, physical function, emotional distress or depression, sleep disturbance, and PIS scores were 12.9 ± 4.1, 14.4 ± 3.9, 9.8 ± 4.4, 13.0 ± 3.6, and 26.4 ± 6.6, respectively. Emotional distress or depression showed floor effects. Good-to-excellent internal consistency was found overall and by language, gender, and age subgroups for all domains (alpha: 0.81-0.93) and poor-to-excellent internal consistency for PIS subgroups (alpha: 0.59-0.91). This study presents reference values and recommendations for using the Canadian version of the NIH minimum dataset for CLBP that can be useful for researchers and clinicians.

Challenges and opportunities for omics-based precision medicine in chronic low back pain

PURPOSE

Chronic low back pain (cLBP) is a common health condition worldwide and a leading cause of disability with an estimated lifetime prevalence of 80-90% in industrialized countries. However, we have had limited success in treating cLBP likely due to its non-specific heterogeneous nature that goes beyond detectable anatomical changes. We propose that omics technologies as precision medicine tools are well suited to provide insight into its pathophysiology and provide diagnostic markers and therapeutic targets. Therefore, in this review, we explore the current state of omics technologies in the diagnosis and classification of cLBP. We identify factors that may serve as markers to differentiate between acute and chronic cases of low back pain (LBP). Finally, we also discuss some challenges that must be overcome to successfully apply precision medicine to the diagnosis and treatment of cLBP.

METHODS

A literature search for the current applications of omics technologies to chronic low back pain was performed using the following search terms- "back pain," "low back pain," "proteomics," "transcriptomics", "epigenomics," "genomics," "omics." We reviewed molecular markers identified from 35 studies which hold promise in providing information regarding molecular insights into cLBP.

RESULTS

GWAS studies have found evidence for the role of single nucleotide polymorphisms (SNPs) associated with pain pathways in individuals with cLBP. Epigenomic modifications in patients with cLBP have been found to be enriched among genes involved in immune signaling and inflammation. Transcriptomics profiles of patients with cLBP show multiple lines of evidence for the role of inflammation in cLBP. The glycomics profiles of patients with cLBP are similar to those of patients with inflammatory conditions. Proteomics and microbiomics show promise but have limited studies currently.

CONCLUSION

Omics technologies have identified associations between inflammatory and pain pathways in the pathophysiology of cLBP. However, in order to integrate information across the range of studies, it is important for the field to identify and adopt standardized definitions of cLBP and control patients. Additionally, most papers have applied a single omics method to a sampling of cLBP patients which have yielded limited insight into the pathophysiology of cLBP. Therefore, we recommend a multi-omics approach applied to large global consortia for advancing subphenotyping and better management of cLBP, via improved identification of diagnostic markers and therapeutic targets.

Low back pain definitions: effect on patient inclusion and clinical profiles

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Differences in sample size and group characteristics were observed in a cohort study depending on the definition of acute low back pain applied.

Introduction:

Numerous definitions of acute low back pain (aLBP) exist. The use of different definitions results in variability in reported prevalence or incidence, conflicting data regarding factors associated with the transition to chronic LBP (cLBP), and hampers comparability among studies.

Objective:

Here, we compare the impact of 3 aLBP definitions on the number of aLBP cases and participants' characteristics and explore the distribution of participants across definitions.

Methods:

A sample of 1264 participants from the Quebec Low Back Pain Study was included. Three definitions of aLBP were used: (1) not meeting the National Institutes of Health (NIH) cLBP definition (“nonchronic”), (2) pain beginning <3 months ago (“acute”), and (3) pain beginning <3 months with a preceding LBP-free period (“new episode”).

Results:

There were 847, 842, and 489 aLBP cases meeting the criteria for the 3 definitions, respectively. Participants included in the “nonchronic” had lower pain interference, greater physical function scores, and fewer participants reporting >5 years of pain than in the other definitions. Half the participants meeting the “acute” definition and one-third of participants meeting the “new episode” definition were also classified as cLBP based on the NIH definition.

Conclusions:

Our results highlight the importance of the definition used for aLBP. Different definitions influence the sample size and clinical profiles (group's characteristics). We recommended that cohort studies examining the transition from aLBP to cLBP ensure that the definitions selected are mutually exclusive (ie, participants included [aLBP] differ from the expected outcome [cLBP]).

Neurophysiological and transcriptomic predictors of chronic low back pain: Study protocol for a longitudinal inception cohort study

Chronic low back pain is one of the most common, costly, and debilitating pain conditions worldwide. Increased mechanistic understanding of the transition from acute to chronic low back and identification of predictive biomarkers could enhance the clinical assessment performed by healthcare providers and enable the development of targeted treatment to prevent and/or better manage chronic low back pain. This study protocol was designed to identify the neurological and transcriptomic biomarkers predictive of chronic low back pain at low back pain onset. This is a prospective descriptive longitudinal inception cohort study that will follow 340 individuals with acute low back pain and 40 healthy controls over 2 years. To analyze the neurophysiological and transcriptomic biomarkers of low back pain, the protocol includes psychological and pain-related survey data that will be collected beginning within 6 weeks of low back pain onset (baseline, 6, 12, 24, 52 weeks, and 2 years) and remotely at five additional time points (8, 10, 16, 20 weeks, and 18 months). Quantitative sensory testing and collection of blood samples for RNA sequencing will occur during the six in-person visits. The study results will describe variations in the neurophysiological and transcriptomic profiles of healthy pain-free controls and individuals with low back pain who either recover to pain-free status or develop chronic low back pain.

Epigenetic signature of chronic low back pain in human T cells

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This study reveals sex-specific DNA methylation signatures in human T cells that discriminate chronic low back pain participants from healthy controls.

Objective:

Determine if chronic low back pain (LBP) is associated with DNA methylation signatures in human T cells that will reveal novel mechanisms and potential therapeutic targets and explore the feasibility of epigenetic diagnostic markers for pain-related pathophysiology.

Methods:

Genome-wide DNA methylation analysis of 850,000 CpG sites in women and men with chronic LBP and pain-free controls was performed. T cells were isolated (discovery cohort, n = 32) and used to identify differentially methylated CpG sites, and gene ontologies and molecular pathways were identified. A polygenic DNA methylation score for LBP was generated in both women and men. Validation was performed in an independent cohort (validation cohort, n = 63) of chronic LBP and healthy controls.

Results:

Analysis with the discovery cohort revealed a total of 2,496 and 419 differentially methylated CpGs in women and men, respectively. In women, most of these sites were hypomethylated and enriched in genes with functions in the extracellular matrix, in the immune system (ie, cytokines), or in epigenetic processes. In men, a unique chronic LBP DNA methylation signature was identified characterized by significant enrichment for genes from the major histocompatibility complex. Sex-specific polygenic DNA methylation scores were generated to estimate the pain status of each individual and confirmed in the validation cohort using pyrosequencing.

Conclusion:

This study reveals sex-specific DNA methylation signatures in human T cells that discriminates chronic LBP participants from healthy controls.

The Experiences of People Living With Chronic Pain During a Pandemic: "Crumbling Dreams With Uncertain Futures"

People living with chronic pain experience multiple challenges in their daily activities. Chronic pain is complex and often provokes life circumstances that create increased social isolation. Living with chronic pain during the pandemic may add additional layers of complexity to their daily lives. The researchers endeavored to explore the experiences of people living with chronic pain during the COVID-19 pandemic. Researchers conducted semi-structured, open-ended interviews about how the pandemic influenced participants' lives. The interviews were recorded and analyzed using an applied philosophical hermeneutics approach. The findings were feeling socially isolated, losing their sense of livinghood, and experiencing augmented stress levels which, in most cases, aggravated their chronic pain. In addition to gaining an in-depth understanding of the needs of people living with chronic pain, these findings may guide policy decisions with the intention of improving health care access and the overall experiences of people living with chronic conditions during a pandemic.

AAAPT Diagnostic Criteria for Acute Low Back Pain with and Without Lower Extremity Pain

OBJECTIVE

Low back pain is one of the most common reasons for which people visit their doctor. Between 12% and 15% of the US population seek care for spine pain each year, with associated costs exceeding $200 billion. Up to 80% of adults will experience acute low back pain at some point in their lives. This staggering prevalence supports the need for increased research to support tailored clinical care of low back pain. This work proposes a multidimensional conceptual taxonomy.

METHODS

A multidisciplinary task force of the ACTTION-APS-AAPM Pain Taxonomy (AAAPT) with clinical and research expertise performed a focused review and analysis, applying the AAAPT five-dimensional framework to acute low back pain.

RESULTS

Application of the AAAPT framework yielded the following: 1) Core Criteria: location, timing, and severity of acute low back pain were defined; 2) Common Features: character and expected trajectories were established in relevant subgroups, and common pain assessment tools were identified; 3) Modulating Factors: biological, psychological, and social factors that modulate interindividual variability were delineated; 4) Impact/Functional Consequences: domains of impact were outlined and defined; 5) Neurobiological Mechanisms: putative mechanisms were specified including nerve injury, inflammation, peripheral and central sensitization, and affective and social processing of acute low back pain.

CONCLUSIONS

The goal of applying the AAAPT taxonomy to acute low back pain is to improve its assessment through a defined evidence and consensus-driven structure. The criteria proposed will enable more rigorous meta-analyses and promote more generalizable studies of interindividual variation in acute low back pain and its potential underlying mechanisms.

EQ-5D-5L and SF-6Dv2 utility scores in people living with chronic low back pain: a survey from Quebec

OBJECTIVE

To describe how chronic low back pain (CLBP) impacts on utility scores and which patients' characteristics most affect these scores in the province of Quebec.

SETTINGS

Province of Quebec, Canada.

PARTICIPANTS

569 adult patients with CLBP.

METHODS AND OUTCOMES

An online survey on low back pain was conducted between October 2018 and January 2019. The EuroQol Five Dimensions (EQ-5D-5L) and the Short Form Six Dimensions version 2 (SF-6Dv2) are two generic preference-based measures used to evaluate health-related quality of life (HRQoL) and provide quality-adjusted life-year utility values.

RESULTS

The number of subjects who agreed to participate was 610, but 41 were excluded because 8 had low back pain for less than 3 months and 33 did not start the survey. A total of 569 subjects were analysed, but only 410 completed the survey up to the EQ-5D-5L or SF-6Dv2 sections. Median (range) of EQ-5D-5L was 0.622 (-0.072 to 0.905), and mean (range) of SF-6Dv2 and EQ-Visual Analogue Scale was 0.561 (0.301-0.829) and 51.0 (0-100), respectively. In all multivariate models, health or life satisfaction increased the health utility score, while pain reduced it. Co-occurring health problems were present for a majority (68%) of participants, mainly fatigue/insomnia (57.4%), musculoskeletal disorder (56.2%) and mental disorder (44%).

CONCLUSION

This study provided utility scores with EQ-5D-5L and SF-6Dv2 in patients with CLBP in Quebec, and results were similar to other studies conducted in different settings. These values were well below those reported in the Quebec general population and highlight the association between CLBP and HRQoL.