The point of no return? Functional disability transitions in patients with and without rheumatoid arthritis: A population-based cohort study

Objective: To assess transition probability between different levels of functional disability (FD) and time spent with FD in patients with versus without rheumatoid arthritis (RA) after RA incidence/index date.

Methods: This retrospective population-based cohort study included Olmsted County, Minnesota residents (1987 ACR criteria met in 1999-2013) and comparators without RA from the same area with similar age, sex and RA incidence/index date. Activities of Daily Living (ADL) were obtained by self-report questionnaires annually since 1999. FD was defined as having difficulty with ≥1 ADL. Multistate modeling was used to estimate the probability of transitioning between FD states.

Results: Five hundred fifty-eight patients with RA and 457 comparators completed ≥2 questionnaires and were included. Patients with RA had increased risk of transitioning from no FD to FD: Hazard Ratio (HR) 2.4; 95%CI:1.9-3.0. Each additional FD at RA onset reduced the probability of returning to no FD by 14%. However, the probability of having ≥1 FD was stable between RA incidence and 10-year follow-up. In the first 15 years of disease, patients with RA spent on average 10.1 years without FD and 3.4 years with ≥1 FD versus 11.6 years and 2.0 years (p<0.001) in comparators.

Conclusion: Patients with RA remain functionally disadvantaged compared to individuals without RA. The likelihood of returning to no FD in RA decreases with each additional preexisting FD. However, the probability of FD does not increase within 10 years of RA onset, potentially reflective of the benefits of disease-modifying treatments in RA.