Objectives: To compare the onset and trajectory of multimorbidity between individuals with and without rheumatoid arthritis (RA). Methods: A matched, retrospective cohort study was completed in a large, U.S., commercial insurance database (MarketScan^{®}) from 2006-2015. Using validated algorithms, RA patients (overall and incident) were age- and sex-matched to non-RA patients. Diagnostic codes for 44 pre-identified chronic conditions were selected to determine the presence (≥2 conditions) and burden (count) of multimorbidity. Cross-sectional comparisons were completed using the overall RA cohort and conditional logistic and negative binomial regression models. Trajectories of multimorbidity were assessed within the incident RA sub-cohort using generalized estimating equations. Results: The overall cohort (n=277,782) and incident sub-cohort (n=61,124) were female predominant (76.5%, 74.1%) with a mean age of 55.6 and 54.5 years. The cross-sectional prevalence (odds ratio [OR] 2.29, 95% CI 2.25-2.34) and burden (ratio of conditions 1.68, 95% CI 1.66-1.70) of multimorbidity were significantly higher in RA than non-RA in the overall cohort. Within the incident RA cohort, RA patients had more chronic conditions than non-RA ( β 1.13, 95% CI 1.10-1.17), and the rate of accruing chronic conditions was significantly higher in RA compared to non-RA (RA x follow-up year, β 0.21, 95%CI 0.20-0.21, P <0.001). Results were similar when including the pre-RA period and in several sensitivity analyses. Conclusions: Multimorbidity is highly prevalent in RA and progresses more rapidly in RA than in non-RA patients during and immediately following RA onset. Therefore, multimorbidity should be aggressively identified and targeted early in the RA disease course.
【저자키워드】 Comorbidity, rheumatoid arthritis, chronic disease, Multimorbidity,