Illness perceptions as an independent predictor of chronic low back pain and pain-related disability: a prospective cohort study

Can a Psychologic Profile Predict Successful Return to Full Duty After a Musculoskeletal Injury?

BACKGROUND

Psychologic variables have been shown to have a strong relationship with recovery from injury and return to work or sports. The extent to which psychologic variables predict successful return to work in military settings is unknown.

QUESTIONS/PURPOSES

In a population of active duty soldiers, (1) can a psychologic profile determine the risk of injury after return to full duty? (2) Do psychologic profiles differ between soldiers sustaining injuries in the spine (thoracic or lumbar) and those with injuries to the lower extremities?

METHODS

Psychologic variables were assessed in soldiers returning to full, unrestricted duty after a recent musculoskeletal injury. Most of these were noncombat injuries from work-related physical activity. Between February 2016 and September 2017, 480 service members who were cleared to return to duty after musculoskeletal injuries (excluding those with high-velocity collisions, pregnancy, or amputation) were enrolled in a study that tracked subsequent injuries over the following year. Of those, we considered individuals with complete 12-month follow-up data as potentially eligible for analysis. Based on that, approximately 2% (8 of 480) were excluded because they did not complete baseline surveys, approximately 2% (11 of 480) were separated from the military during the follow-up period and had incomplete injury data, 1% (3 of 480) were excluded for not serving in the Army branch of the military, and approximately 2% (8 of 480) were excluded because they were not cleared to return to full duty. This resulted in 450 soldiers analyzed. Individuals were 86% (385 of 450) men; 74% (331 of 450) had lower extremity injuries and 26% (119 of 450) had spinal injuries, including soft tissue aches and pains (for example, strains and sprains), fractures, and disc herniations. Time-loss injury within 1 year was the primary outcome. While creating and validating a new prediction model using only psychological variables, 19 variables were assessed for nonlinearity, further factor selection was performed through elastic net, and models were internally validated through 2000 bootstrap iterations. Performance was deciphered through calibration, discrimination (area under the curve [AUC]), R 2 , and calibration in the large. Calibration assesses predicted versus actual risk by plotting the x and y intersection of these values; the more similar predicted risk values are to actual ones, the closer the slope of the line formed by the intersection points of all subjects is to equaling "1" (optimal calibration). Likewise, perfect discrimination (predicted injured versus actual injured) presents as an AUC of 1. Perfect calibration in the large would equal 0 because it represents the average predicted risk versus the actual outcome rate. Sensitivity analyses stratified groups by prior injury region (thoracic or lumbar spine and lower extremity) as well as the severity of injury by days of limited duty (moderate [7-27 days] and severe [28 + days]).

RESULTS

A model comprising primarily psychologic variables including depression, anxiety, kinesiophobia, fear avoidance beliefs, and mood did not adequately determine the risk of subsequent injury. The derived logistic prediction model had 18 variables: R 2 = 0.03, calibration = 0.63 (95% confidence interval [CI] 0.30 to 0.97), AUC = 0.62 (95% CI 0.52 to 0.72), and calibration in the large = -0.17. Baseline psychologic profiles between body regions differed only for depression severity (mean difference 1 [95% CI 0 to 1]; p = 0.04), with greater mean scores for spine injuries than for lower extremity injuries. Performance was poor for those with prior spine injuries compared with those with lower extremity injuries (AUC 0.50 [95% CI 0.42 to 0.58] and 0.63 [95% CI 0.57 to 0.69], respectively) and moderate versus severe injury during the 1-year follow-up (AUC 0.61 [95% CI 0.51 to 0.71] versus 0.64 [95% CI 0.64 to 0.74], respectively).

CONCLUSION

The psychologically based model poorly predicted subsequent injury. This study does not minimize the value of assessing the psychologic profiles of injured athletes, but rather suggests that models looking to identify injury risk should consider a multifactorial approach that also includes other nonpsychologic factors such as injury history. Future studies should refine the most important psychologic constructs that can add the most value and precision to multifactorial models aimed at identifying the risk of injury.

LEVEL OF EVIDENCE

Level III, prognostic study.

Prognostic value of illness perception on changes in knee pain among elderly individuals: Two-year results from the Frederiksberg Cohort study

Objective

To investigate the prognostic value of illness perception (IP) on knee pain, quality of life (QoL) and functional level in elderly individuals reporting knee pain.

Design

A prospective cohort study of 1552 elderly with knee pain comparing two previously established clusters based on the Brief Illness Perception questionnaire. Cluster 1 ("Concerned optimists" [hypothesized unfavorable profile]; n ​= ​642) perceived their knee pain as a greater threat to them than Cluster 2 ("Unconcerned confident" [hypothesized favorable profile]; n ​= ​910). Primary outcome was the change from baseline to year 2 in the KOOS Pain subscale. Secondary outcomes were changes from baseline in quality of life (EuroQol-5 Domain and EQ VAS) and in the KOOS subscales Symptom, Activities of Daily Living, Knee-related QoL and Sports and recreation. Analyses were done on the original Intention-To-Survey (ITS) population, using repeated measures mixed linear models.

Results

Among the ITS population, 841 (54%) responded to the 2-year survey. There was a statistically significant but clinically irrelevant cluster difference in the 2-year change from baseline in KOOS pain (mean difference: 6.0 KOOS points [95% CI: 7.3 to -4.7]) explained by a minor improvement in Cluster 1: (6.2 points) and no changes in Cluster 2: (0.2 points). Comparable results were found across the secondary outcomes. Clinically irrelevant cluster changes in IP were seen.

Conclusion

In a cohort of people with knee pain, IP phenotype (i.e., Clusters) were of no prognostic value for the 2-year changes in pain, function, and QoL. Targeting IP may not be relevant in this patient population.

Trial registration number and date of registration

The Frederiksberg Cohort study was pre-registered at clinicaltrials.gov (NCT03472300) on March 21, 2018.

Anxiety, Disability, and Pain Predict Outcomes of Complex Regional Pain Syndrome: An 8-year Follow-up of a Prospective Cohort

Factors contributing to the varied outcomes of complex regional pain syndrome (CRPS) are not well known. This study aimed to determine whether baseline psychological factors, pain, and disability influence long-term CRPS outcomes. We conducted an 8-year follow-up from a previous prospective study of CRPS outcomes. Sixty-six people diagnosed with acute CRPS were previously assessed at baseline, 6 months, and 12 months and in the current study, 45 were followed up after 8 years. At each timepoint, we measured signs and symptoms of CRPS, pain, disability, and psychological factors. Mixed-model repeated measures were used to identify baseline predictors of CRPS severity, pain, and disability at 8 years. Predictors of greater CRPS severity at 8 years were female sex, greater baseline disability, and greater baseline pain. Predictors of greater pain at 8 years were greater baseline anxiety and disability. The only predictor of greater disability at 8 years was greater baseline pain. Findings suggest CRPS is best understood from a biopsychosocial perspective, and baseline anxiety, pain, and disability may influence the trajectory of CRPS outcomes as far as 8 years later. These variables could be used to identify those at risk of poor outcomes or form targets for early interventions. PERSPECTIVE: This paper presents the findings of the first study to prospectively investigate predictors of CRPS outcomes over 8 years. Baseline anxiety, pain, and disability predicted greater CRPS severity, pain, and disability over 8 years. These factors could identify those at risk of poor outcomes or form targets for early interventions.

The effect of COVID-19 lockdown restrictions on oswestry disability index scores: a comparative cross-sectional study

PURPOSE

Lockdown measures to combat the COVID-19 pandemic restricted social interactions and travel. This retrospective, observational study was conducted to evaluate the effect of lockdown restrictions on Oswestry Disability Index (ODI) scores in patients with spinal conditions.

METHODS

Prospectively collected data from the British Spine Registry were retrospectively analysed in two groups. The study group included patients' baseline pre-operative ODI scores collected during the first national lockdown in the UK between March and May 2020. The reference group included ODI scores recorded during the same period in 2019, before the pandemic. Scores were compared between groups using the Mann-Whitney U test. We also calculated modified scores that omitted responses to questions related to travel and social life. These were compared using Wilcoxon matched-pairs signed-rank test and Bland-Altman analyses.

RESULTS

The median ODI scores for the reference and lockdown groups were 49 and 45, respectively, with no significant differences in the mean ranks (p = 0.068). Comparisons of original and modified ODI scores showed different outcomes for each study group. No significant differences were observed in the lockdown group (p = 0.06). However, for the pre-COVID-19 reference group, there was a significant difference (p < 0.01). Bland-Altman analyses showed reasonable agreement between the methods for calculating ODI in both groups.

CONCLUSION

We found no clinically important differences in ODI scores between the two groups. The findings suggest that the ODI is reliable during lockdown situations and can be used with confidence in the future research using both retrospective and prospective data.

LEVEL OF EVIDENCE

Level 3.

The impact of different intensities and domains of physical activity on analgesic use and activity limitation in people with low back pain: a prospective cohort study with a one-year follow-up

BACKGROUND

Analgesics are the most common form of managing low back pain (LBP). No previous study has examined which domains and intensities of physical activity are most beneficial in reducing the frequency of analgesic use for LBP, and its related activity limitation.

METHODS

This cohort study forms part of the AUstralian Twin low BACK pain study, investigating the impact of physical activity on LBP. Information on demographics, LBP and health-related factors, including physical activity were collected at baseline. Data on the total counts of analgesic use and activity limitation for LBP were collected weekly for one-year. Negative binomial regression models were conducted separately for each type of physical activity. Results were presented as Incidence Rate Ratios (IRR) and 95% Confidence Intervals (CI).

RESULTS

From an initial sample of 366 participants, 86 participants reported counts of analgesic use and 140 recorded counts of activity limitation across the follow up period. The negative binomial regression models for analgesic use counts indicated moderate-vigorous physical activity (IRR 0·97, 95% C.I 0·96-0·99) and physical workload (IRR 1·02, 95% C.I 1·01-1·05) to be significant. For activity limitation counts, significant associations were shown for sedentary time (IRR 1·04, 95% C.I 1·01-1·09) and leisure activity (IRR 0·94, 95% C.I 0·81-0·99).

CONCLUSIONS

Our findings highlight the potential importance of supporting engagement in moderate-vigorous and leisure physical activity, as well as minimising sedentary time and physical workload to reduce the risk of activity limitation and the need for analgesic use in people with LBP.

Beliefs about back pain and associations with clinical outcomes: a primary care cohort study

OBJECTIVE

To investigate associations between beliefs about low back pain (LBP) at baseline and pain intensity and disability at 2-week, 13-week and 52-week follow-up.

DESIGN

Observational cohort study.

SETTING

Primary care private chiropractic clinics in Denmark.

PARTICIPANTS

A total of 2734 adults consulting a chiropractor for a new episode of LBP, with follow-up data available from 71%, 61% and 52% of the participants at 2, 13 and 52 weeks, respectively.

OUTCOME MEASURES

Beliefs about LBP were measured by the Back Belief Questionnaire (BBQ) before consulting the chiropractor. Pain (Numerical Rating Scale 0-10) and disability (the Roland-Morris Disability Questionnaire) were measured at baseline and after 2, 13 and 52 weeks. Associations were explored using longitudinal linear mixed models estimating interactions between BBQ and time, and by estimating associations between single items of BBQ and 13-week outcomes.

RESULTS

More positive beliefs about LBP were weakly associated with a reduction in pain at 2 weeks (β interaction BBQ#Time=-0.02 (95% CI -0.04 to -0.001)), at 13 weeks (-0.03 (95% CI -0.05 to -0.01)) and at 52 weeks of follow-up (-0.03 (95% CI -0.05 to -0.01); p=0.003). For disability, the association was uncertain (p=0.7). The item 'Back trouble means periods of pain for the rest of one's life' had the strongest association with both reduction in pain (-0.29, 95% CI -0.4 to -0.19, p<0.001) and disability (-2.42, 95% CI -3.52 to -1.33, p<0.001) at 13-week follow-up.

CONCLUSION

Positive beliefs regarding LBP, measured by the BBQ, were associated with a reduction in pain intensity at both short-term and long-term follow-up. However, the association was weak, and the clinical relevance is therefore questionable. No clear association was demonstrated between beliefs and disability. This study did not show promise that back beliefs as measured by the BBQ were helpful for predicting or explaining the course of LBP in this setting.