Incident rheumatoid arthritis and work loss: a nationwide sibling comparison study.

objectivesRheumatoid arthritis (RA) has been associated with substantial work loss, but advances in treatment have improved clinical outcomes for patients over time calling for an updated assessment. We therefore aimed to examine calendar trends in the association between RA diagnosis and work loss.

methodsThis study included 3850 patients with RA, diagnosed between 2006 and 2020, aged 30-60 years, and their 4422 same-sex siblings. Data on work loss (the sum of sick leave and disability days) were retrieved from the Swedish Social Insurance Agency, from 3 years before up to 10 years after diagnosis. Analyses were stratified by diagnosis period (2006-2011 vs 2012-2020).

resultsStarting 13 months before RA diagnosis and peaking in the year thereafter, patients with RA experienced more work loss than their same-sex siblings. This excess was smaller during 2012-2020 than 2006-2011 (26 vs 47 days annually, P < 0.001). Patients diagnosed in 2012-2020 also had faster declines in work loss 2-10 years post-diagnosis than those diagnosed 2006-2012, with a smaller difference vs same-sex siblings (11 vs 29 days annually; P = 0.001). Work loss was highly skewed, with a small proportion of patients contributing most of the work loss days.

conclusionCompared with their same-sex siblings as a surrogate for the counterfactual ideal, RA is still associated with considerable work loss. This difference has, however, declined in recent years, possibly due to earlier diagnosis and improved treatment.