The value of interdisciplinary treatment for sickness absence in chronic pain: A nationwide register-based cohort study.

BACKGROUND Interdisciplinary treatment (IDT) is an internationally recommended intervention for chronic pain, despite inconclusive evidence of its effects on sickness absence. METHODS With data from 25,613 patients in Swedish specialist healthcare, we compared sickness absence, in the form of both sick leave and disability pensions, over a 5-year period between patients either allocated to an IDT programme or to other/no interventions (controls). To obtain population-average estimates, a Markov multistate model with theory-based inverse probability weights was used to compute both the proportion of patients on sickness absence and the total sickness absence duration. RESULTS IDT patients were more likely than controls to receive sickness absence benefits at any given time (baseline: 49% vs. 46%; 5-year follow-up: 36% vs. 35%), and thereby also had a higher total duration, with a mean (95% CI) of 67 (87, 48) more days than controls over the 5-year period. Intriguingly, sick leave was higher in IDT patients (563 [552, 573] vs. 478 [466, 490] days), whereas disability pension was higher in controls (152 [144, 160] vs. 169 [161, 178] days). CONCLUSION Although sickness absence decreased over the study period in both IDT patients and controls, we found no support for IDT decreasing sickness absence more than other/no interventions in chronic pain patients. SIGNIFICANCE In this large study of chronic pain patients in specialist healthcare, sickness absence is compared over a 5-year period between patients in an interdisciplinary treatment programme and other/no interventions. Sickness absence decreased over the study period in bothgroups; however, there was no support forthat it decreased more with interdisciplinary treatment than alternative interventions.