Objectives This study aimed to characterize long-term labor market participation from five years before to five years after assessment at departments of occupational medicine among patients referred with low-back pain (LBP) and to compare these patterns with those in a matched general working population. Secondary objectives were to assess subgroup differences and time to return to work.

Methods In this nationwide register-based cohort study, we included Danish residents aged 18–60 years referred for assessment (N=8256) and matched comparators (1:5 on sex, age, and calendar year; N=41 280). Using weekly register data, we calculated the prevalence of different labor market states before and after assessment as well as propensity score-weighted prevalence differences and ratios, and we performed stratified analyses. We estimated the five-year cumulative incidence of return to work among individuals on temporary public benefits using the Aalen–Johansen estimator.

Results At assessment, 37% of patients were working versus 83% of comparators. Five years post-assessment, 40% of patients were working and 32% received permanent health-related public benefits. We observed substantial heterogeneity, with larger deficits in work participation in several subgroups. Among patients on temporary public benefits at assessment, the five-year cumulative incidence of return to work was 42%, with no increase in overall work prevalence.

Conclusions LBP patients had persistently poorer labor market participation than matched comparators, with declines already evident one year before assessment. Prognosis was particularly poor among older patients, those with weaker labor market participation at assessment, and those with comorbidities. These findings highlight the need for early identification and timely intervention and referral.

Key terms back pain; cohort study; Denmark; labor market participation; low-back pain; musculoskeletal disorder; occupational epidemiology; occupational medicine; propensity score; register-based cohort study; return to work

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