Patients at risk for long-term sick leave because of low back pain

Background contextTen percent of patients with low back pain (LBP) are not able to resume work within 3 months of sick leave, accounting for 90% of all medical and indemnity costs.PurposeTo quantify the relative contribution of sociodemographic, clinical, occupational, and psychological risk factors in determining the non–return to work after 3 months of compensated LBP and to develop a screening tool to identify patients who require further guidance and rehabilitation.Study design/settingA 6-month prospective cohort study of disabled workers applying for compensation benefit because of LBP during a 6-month period in the Belgian compulsory health insurance system.Patient sampleThree hundred and forty-six patients.Outcome measuresPatients unable to resume work within 3 months of sick leave were classified as bad outcomes.MethodsConsecutively, injured workers applying for income replacement benefits between October 2003 and March 2004 because of LBP were followed 6 months after the start of the sick leave period. All subjects underwent a standardized physical examination and completed a battery of 12 self-report questionnaires.ResultsForty-seven percent of the population had not resumed work 3 months after the start of the sick leave period. The risk factors for sickness absence more than 3 months were Oswestry disability index (odds ratio for each point increase: 1.04; 95% confidence interval: 1.02–1.06), fear of avoidance severity score (odds ratio for each point increase: 1.05; confidence interval: 1.02–1.09), blue collar worker (odds ratio: 2.18; confidence interval: 1.21–3.92), LBP for less than 12 weeks before sick leave (odds ratio: 0.32; confidence interval: 0.17–0.64), and pain behavior (odds ratio for each point increase: 1.72; confidence interval: 1.25–2.39). A multivariate screening test based on five questions identified 80% of the patients unable to resume work after 3 months of sick leave (specificity: 56.6; cut off: 0.4).ConclusionsA questionnaire comprising a limited set of items allows a practical screening of LBP patients unlikely to resume work.