Longterm Work Productivity Costs Due to Absenteeism and Permanent Work Disability in Patients with Early Rheumatoid Arthritis: A Nationwide Register Study of 7831 Patients

Objective. To estimate the development and potential disproportional distribution of longterm productivity costs (PC) and their determinants leading to work absenteeism and permanent work disability in working-aged patients with early rheumatoid arthritis (RA). Methods. A cohort of subjects with early RA was created by identifying the new cases of RA from the national drug reimbursement register that had been granted a special reimbursement for their antirheumatic medications for RA from 2000-2007. The dataset was enriched by cross-linking with other national registries detailing work absenteeism days and permanent disability pensions. In the base case, the human capital approach was applied to estimate PC based on subjects' annual number of absenteeism days and incomes. Hurdle regression analysis was applied to study the determinants of PC. Results. Among the 7831 subjects with early RA, the mean (bootstrapped 95% CI) annual PC per person-observation year was (sic)4800 (4547-5070). The annual PC declined after the first year of RA diagnosis, but increased significantly in subsequent years. In addition, the PC was heavily disproportionally concentrated in a small fraction of patients with RA, because only around 20% of patients accounted for the majority of total annual PC. The initiation of active drug treatment during the first 3 months after RA diagnosis significantly reduced the cumulative PC when compared with no drug treatment. Conclusion. The longterm PC increased significantly in parallel with years elapsing after RA diagnosis. Further, the majority of these PC are incurred by a small proportion of patients.