Correlations between pain and function in a longitudinal low back pain cohort

Psychometric testing of Ibadan low back pain disability questionnaire

Background

The Ibadan Low Back Pain Disability Questionnaire (ILBPDQ) was developed to meet the need for a LBP treatment outcome measure that was appropriate for the Nigerian culture and environment. The objective of this study was to determine the psychometric properties of ILBPDQ.

Methods

This study used the validation design. One hundred and forty-two participants with LBP (LBPPs) and 142 age and sex-matched participants without LBP (NLBPPs) were included. The LBPPs were recruited consecutively from Physiotherapy clinics of selected tertiary hospitals in the six geopolitical zones of Nigeria. Both LBPPs and NLBPPs completed the ILBPDQ - the LBPPs completed the Numerical Pain Rating Scale (NPRS). The ILBPDQ was completed by 113 LBPPs two days after initial assessment. Sixty-four of the LBPPs received physiotherapy for 5-weeks, after which they were reassessed using ILBPDQ and NPRS.

Results

ILBPDQ score of LBPPs was significantly higher than that of NLBPPs (construct validity) and LBPPs NPRS score correlated significantly with their ILBPDQ score (r = 0.50) at baseline and post intervention (r =0.35) (divergent validity). ILBPDQ scores at baseline and 48 hours later for LBPPs correlated significantly (Intra Class Correlation =0.80) (test re -test reliability). Cronbach's α for ILBPDQ was 0.84 (internal consistency). The postintervention ILBPDQ and NPRS scores for LBPPs were significantly lower than their pre-intervention ILBPDQ scores (responsiveness) and NPRS scores. The changes in ILBPDQ and NPRS scores of the LBPPs correlated significantly (r =0.62) (responsiveness).

Conclusion

The ILBPDQ demonstrated evidence of validity, reliability and responsiveness.

Funding

University of Ibadan Senate Research Grant.

Comparison of two different electrotherapy methods in low back pain treatment

OBJECTIVE

To investigate the efficacy of High Intensity Laser Therapy (HILT) and Transcutaneous Electrical Nerve Stimulation (TENS) in low back pain (LBP).

METHODS

Forty patients aged between 18 to 60 were included in this study. The patients were randomized into two groups as TENS (Group I) and HILT (Group II). The severity of pain was measured by Visual Analog Scale (VAS), and the range of motion (ROM) of the joint was measured by goniometer. The Oswestry Disability Questionnaire (ODQ) was used to assess the effect of LBP on daily living activities, and the Beck Depression Inventory (BDI) was used to assess depression. All patients were taken into physical therapy program for 5 days a week for a total of 20 sessions. Patients in Group I received ultrasound, hot pack and HILT, while the patients in Group II received ultrasound, hot pack and TENS.

RESULTS

In the comparison of post-treatment improvements, among all parameters only VAS score had a significant difference in favor of Group I.

CONCLUSIONS

The study demonstrated that HILT is more effective than TENS in terms of pain reduction and that HILT can be used as an alternative to TENS.

Correlations between lumbar neuromuscular function and pain, lumbar disability in patients with nonspecific low back pain: A cross-sectional study

This study aims to examine the correlations between lumbar neuromuscular function and pain, lumbar disability in patients with nonspecific low back pain (NSLBP).Ninety patients, with ages 18 to 37 years old, with NSLBP were recruited in this study. The lumbar neuromuscular function was tested by the CON-TREX multijoint isokinetic test and training machine. This study uses the visual analog scale (VAS) and Roland-Morris Disability Questionnaire (RMDQ) to evaluate the pain and the dysfunction index of patients who have low back pain, respectively.Pearson correlation coefficient is used to evaluate the correlation between lumbar neuromuscular function and the VAS and RMDQ scores. VAS and RMDQ scores have correlations with the proprioception in the flexion of the lumbar vertebra flexion; the peak torque of both flexion and extension muscle groups; and average power and endurance at different angular velocities. The decrease of lumbar muscle strength, endurance, and lumbar proprioception of the lumbar vertebra leads to an increase in pain intensity and lumbar disability.This study suggests that patients with chronic low back pain require targeted training in muscle strength, endurance, and lumbar proprioception, providing a theoretical basis for prevention and treatment of chronic NSLBP patients.

Predictors of Back Pain in Firefighters

The purpose of this study was to identify variables—that is, demographic factors (age, history of back pain, body mass index [BMI], and waist circumference), occupational stress, job satisfaction, perceived supervisor support, and physical fitness—that predict back pain in firefighters. Firefighters, an occupational group at high risk for back injury, perform many job tasks under hazardous work conditions. A nonexperimental, correlational design was used to study a convenience sample of 298 male firefighters who completed study questionnaires. Almost one third (30.20%) of the firefighters reported current back pain. The set of factors that predicted current back pain in firefighters included occupational stress, age, history of back pain, and BMI—pseudo R2 = .351. Further studies should validate the model and explore relationships among perceived supervisor support, occupational stress, and job satisfaction in other occupational groups, including nurses and police officers.

Effect of Adding McKenzie Syndrome, Centralization, Directional Preference, and Psychosocial Classification Variables to a Risk-Adjusted Model Predicting Functional Status Outcomes for Patients With Lumbar Impairments

Study Design Retrospective cohort. Background Patient-classification subgroupings may be important prognostic factors explaining outcomes. Objectives To determine effects of adding classification variables (McKenzie syndrome and pain patterns, including centralization and directional preference; Symptom Checklist Back Pain Prediction Model [SCL BPPM]; and the Fear-Avoidance Beliefs Questionnaire subscales of work and physical activity) to a baseline risk-adjusted model predicting functional status (FS) outcomes. Methods Consecutive patients completed a battery of questionnaires that gathered information on 11 risk-adjustment variables. Physical therapists trained in Mechanical Diagnosis and Therapy methods classified each patient by McKenzie syndromes and pain pattern. Functional status was assessed at discharge by patient-reported outcomes. Only patients with complete data were included. Risk of selection bias was assessed. Prediction of discharge FS was assessed using linear stepwise regression models, allowing 13 variables to enter the model. Significant variables were retained in subsequent models. Model power (R(2)) and beta coefficients for model variables were estimated. Results Two thousand sixty-six patients with lumbar impairments were evaluated. Of those, 994 (48%), 10 (<1%), and 601 (29%) were excluded due to incomplete psychosocial data, McKenzie classification data, and missing FS at discharge, respectively. The final sample for analyses was 723 (35%). Overall R(2) for the baseline prediction FS model was 0.40. Adding classification variables to the baseline model did not result in significant increases in R(2). McKenzie syndrome or pain pattern explained 2.8% and 3.0% of the variance, respectively. When pain pattern and SCL BPPM were added simultaneously, overall model R(2) increased to 0.44. Although none of these increases in R(2) were significant, some classification variables were stronger predictors compared with some other variables included in the baseline model. Conclusion The small added prognostic capabilities identified when combining McKenzie or pain-pattern classifications with the SCL BPPM classification did not significantly improve prediction of FS outcomes in this study. Additional research is warranted to investigate the importance of classification variables compared with those used in the baseline model to maximize predictive power. Level of Evidence Prognosis, level 4. J Orthop Sports Phys Ther 2016;46(9):726-741. Epub 31 Jul 2016. doi:10.2519/jospt.2016.6266.

Evaluating Clinical Practice Guidelines Based on Their Association with Return to Work in Administrative Claims Data

OBJECTIVE

To examine the association between non-adherence to clinical practice guidelines (CPGs) and time to return to work (RTW) for patients with workplace injuries.

DATA SOURCES/STUDY SETTING

Secondary analysis of medical billing and disability data for 148,199 for shoulder and back injuries from a workers' compensation insurer.

STUDY DESIGN

Cox proportional hazard regression is used to estimate the association between time to RTW and receipt of guideline-discordant care. We test the robustness of our findings to an omitted confounding variable.

DATA COLLECTION

Collected by the insurer from the time an injury was reported, through recovery or last follow-up.

PRINCIPAL FINDINGS

Receiving guideline-discordant care was associated with slower RTW for only some guidelines. Early receipt of care, and getting less than the recommended amount of care, were correlated with faster RTW. Excessive physical therapy, bracing, and injections were associated with slower RTW.

CONCLUSIONS

There is not a consistent relationship between performance on CPGs and RTW. The association between performance on CPG and RTW is difficult to measure in observational data, because analysts cannot control for omitted variables that affect a patient's treatment and outcomes. CPGs supported by observational studies or randomized trials may have a more certain relationship to health outcomes.

Subjective health complaints, functional ability, fear avoidance beliefs, and days on sickness benefits after work rehabilitation - a mediation model

Background

Long-term sick leave and withdrawal from working life is a concern in western countries. In Norway, comprehensive inpatient work rehabilitation may be offered to sick listed individuals at risk of long-term absence from work. Knowledge about prognostic factors for work outcomes after long-term sick leave and work rehabilitation is still limited. The aim of this study was to test a mediation model for various hypothesized biopsychosocial predictors of continued sick leave after inpatient work rehabilitation.

Methods

One thousand one hundred fifty-five participants on long-term sick leave from eight different work rehabilitation clinics answered comprehensive questionnaires at arrival to the clinic, and were followed with official register data on sickness benefits for 3 years. Structural equation models were conducted, with days on sickness benefits after work rehabilitation as the outcome.

Results

Fear avoidance beliefs for work mediated the relation between both musculoskeletal complaints and education on days on sickness benefits after work rehabilitation. The relation between musculoskeletal complaints and fear avoidance beliefs for work was furthermore fully mediated by poor physical function. Previous sick leave had a strong independent effect on continued sick leave after work rehabilitation. Fear avoidance beliefs for work did not mediate the small effect of pseudoneurological complaints on continued sick leave. Poor coping/interaction ability was neither related to continued sick leave nor fear avoidance beliefs for work.

Conclusions

The mediation model was partly supported by the data, and provides some possible new insight into how fear avoidance beliefs for work and functional ability may intervene with subjective health complaints and days on sickness benefits after work rehabilitation.

Returning to work following low back pain: towards a model of individual psychosocial factors

PURPOSE

The aim of this paper is to develop and test a model of direct and indirect relationships among individual psychosocial predictors of return-to-work (RTW) outcomes following the onset of low back pain (LBP).

METHODS

We utilize secondary analysis of a larger study of adults seeking treatment for work-related LBP with recent onset. In total, 241 participants who completed a baseline survey, a short follow-up survey, and a longer follow-up survey after 3 months were included in our analyses. The participants were required to have LBP with onset of less than 14 days, be 18 years or older, and be fluent in English or Spanish. The analyses utilized structural equation models to test the direct and indirect relationships among the variables and RTW outcomes at 3 months.

RESULTS

Our results indicated a good fit for our model (χ2 = 69.59, df = 45, p < .05; RMSEA = .05; CFI = .95; WRMR = .61). Pain, catastrophizing, fear-avoidance beliefs, organizational support, and RTW confidence were all found to have indirect relationships with the outcomes. RTW confidence and RTW expectations were found to have direct relationships with the outcomes.

CONCLUSIONS

The process of returning to work after an episode of LBP is a complex process involving many interrelated factors. Understanding the relationships among critical individual factors in the RTW process may be important for the treatment and rehabilitation of those with LBP. Results suggest that if injured workers are struggling with fear avoidance, pain catastrophizing and confidence issues, they might benefit from the application of cognitive behavioral therapy techniques.

Prognostic factors of prolonged disability in patients with chronic low back pain and lumbar degeneration in primary care: a cohort study

STUDY DESIGN

A cohort study with 1-year follow-up.

OBJECTIVE

To identify prognostic factors in patients with chronic nonspecific low back pain (LBP).

SUMMARY OF BACKGROUND DATA

The factors (e.g., sociodemographical, low back-related, radiological, and biological) associated with persistent pain and disability for patients with chronic nonspecific LBP are uncertain. Furthermore, sparse information exists about the relationship between biological factors like impaired fasting glucose tolerance and chronic nonspecific LBP.

METHODS

The participants consisted of 250 patients with nonspecific LBP of more than 6 months duration and degenerative lumbar osteoarthritis. The patients were originally recruited for a randomized controlled trial from the clinics of general practitioners, physiotherapists, and chiropractors. Potential predictors were evaluated at baseline. The outcome was absolute level of pain-related disability (Roland-Morris Disability Questionnaire [RMDQ]) at 1 year. The association between potential prognostic factors and the outcome was analyzed with multivariate linear backward regression.

RESULTS

At baseline and 1 year, the RMDQ scores were 9.5 and 5.1 points, respectively. Mean (SD) baseline values for body mass index (BMI), EuroQol (EQ)-index, EQ-visual analogue scale were 25.4 (4.3), 0.60 (0.3), and 61.2 (20.8), respectively. Higher pain-related disability levels (1-year RMDQ score) were associated with 6.1 mmol/L or more fasting glucose level at baseline (β, 3.7; 95% confidence interval [CI], 1.2-6.1; P = 0.00), baseline pain-related disability (β 0.2; 95% CI, 0.1-0.4; P = 0.00), BMI (β, 0.2; 95% CI, 0.1-0.3; P < 0.03), EQ-index (β, -4.5; 95% CI, 6.9 to 2.1; P = 0.00), and EQ-visual analogue scale (β, 0.3; 95% CI, -0.6 to -0.0; P = 0.03). However, a limited number of patients had 6.1 mmol/L or more of fasting glucose level at baseline (13/250 patients). The imaging findings, modic changes, and high intensity zones had no predictive ability.

CONCLUSION

Increased pain-related disability at 1 year was seen in patients with impaired fasting glucose tolerance, greater pain-related disability, higher BMI, and lower quality of life at baseline.

Analyzing repeated data collected by mobile phones and frequent text messages. An example of low back pain measured weekly for 18 weeks

BACKGROUND

Repeated data collection is desirable when monitoring fluctuating conditions. Mobile phones can be used to gather such data from large groups of respondents by sending and receiving frequently repeated short questions and answers as text messages.The analysis of repeated data involves some challenges. Vital issues to consider are the within-subject correlation, the between measurement occasion correlation and the presence of missing values.The overall aim of this commentary is to describe different methods of analyzing repeated data. It is meant to give an overview for the clinical researcher in order for complex outcome measures to be interpreted in a clinically meaningful way.

METHODS

A model data set was formed using data from two clinical studies, where patients with low back pain were followed with weekly text messages for 18 weeks. Different research questions and analytic approaches were illustrated and discussed, as well as the handling of missing data. In the applications the weekly outcome "number of days with pain" was analyzed in relation to the patients' "previous duration of pain" (categorized as more or less than 30 days in the previous year).Research questions with appropriate analytical methods 1: How many days with pain do patients experience? This question was answered with data summaries. 2: What is the proportion of participants "recovered" at a specific time point? This question was answered using logistic regression analysis. 3: What is the time to recovery? This question was answered using survival analysis, illustrated in Kaplan-Meier curves, Proportional Hazard regression analyses and spline regression analyses. 4: How is the repeatedly measured data associated with baseline (predictor) variables? This question was answered using generalized Estimating Equations, Poisson regression and Mixed linear models analyses. 5: Are there subgroups of patients with similar courses of pain within the studied population? A visual approach and hierarchical cluster analyses revealed different subgroups using subsets of the model data.

CONCLUSIONS

We have illustrated several ways of analysing repeated measures with both traditional analytic approaches using standard statistical packages, as well as recently developed statistical methods that will utilize all the vital features inherent in the data.

Using intake and change in multiple psychosocial measures to predict functional status outcomes in people with lumbar spine syndromes: a preliminary analysis

BACKGROUND

Managing patients with lumbar spine syndromes who are seeking outpatient physical therapy represents a complex problem where psychosocial constructs such as fear-avoidance beliefs regarding physical activities or work activities, somatization, and depressive symptoms may affect functional status (FS) outcomes.

OBJECTIVE

The purpose of this study was to determine whether intake or changes in fear-avoidance beliefs regarding physical or work activities, somatization, and depressive symptoms assessed simultaneously affect FS outcomes prediction.

DESIGN

This study was a secondary analysis of prospectively collected, longitudinal, observational cohort data.

METHODS

Data analyzed were from adult patients (n=323) with lumbar syndromes classified as elevated versus not elevated on single-item screening instruments for fear-avoidance beliefs regarding physical or work activities, somatization, and depressive symptoms at intake and discharge. Prediction of minimal clinically important difference in FS was assessed separately for intake and change from intake to discharge classifications using logistic regression models controlling for important variables.

RESULTS

Intake and change models were strong (McFadden rho-squared values=.31 and .49, respectively). Patients classified as not elevated in fear-avoidance beliefs regarding physical activities but elevated in fear-avoidance beliefs regarding work activities, somatization, and depressive symptoms at intake were 5 out of 100 times less likely to report clinically important outcomes compared with being elevated in each measure. Patients not elevated in fear-avoidance beliefs regarding work activities and somatization at intake and discharge were 8 to 14 times more likely to report clinically important outcomes compared with being elevated in each measure.

LIMITATIONS

Sample size was limited. Data analyses were retrospective with no control of missing data.

CONCLUSIONS

Combinations of multiple psychosocial constructs were important predictors of FS outcomes and may assist patient management by: (1) identifying patients with elevated psychosocial constructs at intake and (2) tracking change in psychosocial variables for improved outcomes prediction. This model may prove helpful for future clinical and research applications to determine optimal psychosocial screening methods.