To explore differences in health-related benefit status over 3 years, focusing on patterns of sick leave, work assessment allowance and disability benefits, between people who underwent rehabilitation and a matched control group.

Prospective longitudinal multicentre cohort study using registry data over three consecutive years.

Secondary specialist rehabilitation services at 17 institutions across Norway.

Patients (n=2710), 42% with rheumatic and musculoskeletal diseases, aged 18–65 years referred for multidisciplinary rehabilitation at one of the participating institutions. They were propensity score matched with 37 760 controls from the national sick leave registry, based on sociodemographic factors and health-related benefit status.

Multidisciplinary rehabilitation programmes, commonly lasting 3 weeks (range: 1 week to 6 months), tailored to individual needs.

Days on health-related benefits (sick leave, work assessment allowance (WAA) and disability benefits) were quantified as lost workdays per month. Differences between groups were analysed using Generalised Estimating Equations across three consecutive years: the year before rehabilitation, the rehabilitation year and the year after rehabilitation.

The rehabilitation group had more days on health-related benefits per month than controls throughout the observation period. During the rehabilitation year, they had on average 1.7 more days on sick leave (95 % CI 1.3 to 1.9), 2.3 more WAA days (95% CI 1.9 to 2.7) and 0.2 more days on disability benefits (95% CI 0.1 to 0.3). In the year after rehabilitation, they had 0.6 fewer days on sick leave (95% CI –0.8 to –0.3), but 3.7 more days on WAA (95% CI 3.1 to 4.2) and 0.6 more days on disability benefits (95% CI 0.4 to 0.8). Patterns were similar for the subgroup with rheumatic and musculoskeletal diseases.

People undergoing rehabilitation had more days on health-related benefits and a greater increase in long-term benefits, even after matching, indicating a higher disease and support burden than controls. Tailoring interventions and health-related benefits is an essential aspect of rehabilitation for people with complex work participation needs. Future research should include longer observation periods to explore long-term outcomes of rehabilitation.

NCT03764982