STUDY DESIGN: A cohort study of patients with nonspecific low back pain (LBP) participated in a 4-week multidisciplinary rehabilitation program. OBJECTIVE: To identify factors that predict work retention 24 months after treatment in patients with nonspecific LBP. SUMMARY OF BACKGROUND DATA: There is evidence that select physical, psychologic, and psychosocial factors are related to positive outcome for work-related nonspecific LBP. However, there is very little information related to work retention following an episode of nonspecific LBP. This is an exploratory study to identify select physical and psychosocial factors related to work retention. METHODS: Patients who returned to work after treatment (n = 67) were followed for 2 years. Physical baseline measures included tests of flexibility, strength, and functional capacity. Psychosocial baseline measures were The Symptoms Checklist 90-R, The Pain Beliefs and Perceptions Inventory, The Oswestry Scale of perceived disability, The Work Stress Inventory, and The Quality of Life Scale. All physical parameters, perceived disability, and quality of life were tested before and after treatment. The dependent variable, work retention, was defined as the number of days that the subject worked during the 2-year follow-up period. Survival analysis was used to establish the predictive model. RESULT: The average time out of work before treatment was 9 months (standard deviation 12.8) for 67 subjects (mean age 40 years [standard deviation 9.6]), including 18 females and 49 males. There were 18 participants (25%) that had interruption of work retention at follow-up. Average work retention was 362 days (range 47-682). Variables that reached a P value of <0.10 in the bivariate analysis were included in the multivariate analysis. They were trunk flexion (hazard ratio [HR = 2.4], 95% confidence interval [CI] 1.24-4.38; P = 0.01), trunk extension (HR = 2.1, 95% CI 1.02-4.16; P = 0.04), the somatization scale from the Symptom Checklist 90 revised (HR = 2.0, 95% CI 1.03-4.05; P = 0.04), and the obsessive-compulsiveness scale from the Symptom Checklist 90 revised (HR = 0.4, 95% CI 0.12-1.15; P = 0.09). Results showed that post-test trunk flexion, somatization, and obsessive compulsiveness predicted work retention (final trunk flexion HR = 2.5 [95% CI 1.26-4.79; P = 0.01], somatization scale HR = 2.5 [95% CI 1.25-4.93; P = 0.01], and obsessive compulsion HR = 0.2 [95% CI 0.07-0.77; P = 0.02]). CONCLUSION: Psychosocial and physical factors are associated with work retention for patients with nonspecific LBP. The predictive value of certain constructs may vary with the time when they are assessed and how outcome is operationalized. Further studies are needed to confirm these findings.
STUDY DESIGN: A cohort study of patients with nonspecific low back pain (LBP) participated in a 4-week multidisciplinary rehabilitation program. OBJECTIVE: To identify factors that predict work retention 24 months after treatment in patients with nonspecific LBP. SUMMARY OF BACKGROUND DATA: There is evidence that select physical, psychologic, and psychosocial factors are related to positive outcome for work-related nonspecific LBP. However, there is very little information related to work retention following an episode of nonspecific LBP. This is an exploratory study to identify select physical and psychosocial factors related to work retention. METHODS:Patients who returned to work after treatment (n = 67) were followed for 2 years. Physical baseline measures included tests of flexibility, strength, and functional capacity. Psychosocial baseline measures were The Symptoms Checklist 90-R, The Pain Beliefs and Perceptions Inventory, The Oswestry Scale of perceived disability, The Work Stress Inventory, and The Quality of Life Scale. All physical parameters, perceived disability, and quality of life were tested before and after treatment. The dependent variable, work retention, was defined as the number of days that the subject worked during the 2-year follow-up period. Survival analysis was used to establish the predictive model. RESULT: The average time out of work before treatment was 9 months (standard deviation 12.8) for 67 subjects (mean age 40 years [standard deviation 9.6]), including 18 females and 49 males. There were 18 participants (25%) that had interruption of work retention at follow-up. Average work retention was 362 days (range 47-682). Variables that reached a P value of <0.10 in the bivariate analysis were included in the multivariate analysis. They were trunk flexion (hazard ratio [HR = 2.4], 95% confidence interval [CI] 1.24-4.38; P = 0.01), trunk extension (HR = 2.1, 95% CI 1.02-4.16; P = 0.04), the somatization scale from the Symptom Checklist 90 revised (HR = 2.0, 95% CI 1.03-4.05; P = 0.04), and the obsessive-compulsiveness scale from the Symptom Checklist 90 revised (HR = 0.4, 95% CI 0.12-1.15; P = 0.09). Results showed that post-test trunk flexion, somatization, and obsessive compulsiveness predicted work retention (final trunk flexion HR = 2.5 [95% CI 1.26-4.79; P = 0.01], somatization scale HR = 2.5 [95% CI 1.25-4.93; P = 0.01], and obsessive compulsion HR = 0.2 [95% CI 0.07-0.77; P = 0.02]). CONCLUSION:Psychosocial and physical factors are associated with work retention for patients with nonspecific LBP. The predictive value of certain constructs may vary with the time when they are assessed and how outcome is operationalized. Further studies are needed to confirm these findings.