Objective: To investigate the effect of TNF-antagonist treatment on work-force participation in rheumatoid arthritis (RA) patients.
Methods: Data from the Stockholm anti-TNFα follow-up registry (STURE) were used in this observational study. RA patients (n=594) aged 18-55y, (mean±SD 40±9) followed for up to five years were included with hours worked/week as the main outcome measure. Analyses were performed unadjusted and adjusted for baseline age, disease duration, HAQ, DAS28 and pain score.
Results: At baseline patients worked a mean 20h/week (SD 18). In unadjusted analyses, significant improvements in hours worked/week were observed in patients already at six months +2.4h (1.3 to 3.5; mean, 95% confidence interval (95%CI)) with further increases compared to baseline at the one-year (+4.0h, 2.4 to 5.6) and two-year follow-up (+6.3h, 4.2 to 8.4). The trajectory appeared to stabilise at the 3year (+6.3h, 3.6 to 8.9), 4year (+5.3h, 2.3 to 8.4) and 5year follow-up (+6.6h, 3.3 to 10.0). In a mixed piecewise linear regression model, adjusted for age, sex, baseline disease activity, function and pain, an improvement of +4.2h/week was estimated for the first year followed by an added improvement of +0.5h/week annually during the years thereafter. Over five years of treatment, the expected indirect cost gain corresponded to 40% of the annual anti-TNF drug cost in patients continuing treatment.
Conclusion: Data from this population-based registry indicate that biologic therapy is associated with increases in work-force participation in a group typically expected to experience progressively deteriorating work ability. This could result in significant indirect cost benefits to society.