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, US commercial insurance database (MarketScan) from 2006 to 2015. Using validated algorithms, patients with RA (overall and incident) were age-matched and sex-matched to patients without RA. Diagnostic codes for 44 preidentified 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 subcohort using generalised estimating equations.
Results The overall cohort (n=277 782) and incident subcohort (n=61 124) were female predominant (76.5%, 74.1%) with a mean age of 55.6 years and 54.5 years, respectively. The cross-sectional prevalence (OR 2.29, 95% CI 2.25 to 2.34) and burden (ratio of conditions 1.68, 95% CI 1.66 to 1.70) of multimorbidity were significantly higher in RA than non-RA in the overall cohort. Within the incident RA cohort, patients with RA had more chronic conditions than non-RA (β 1.13, 95% CI 1.10 to 1.17), and the rate of accruing chronic conditions was significantly higher in RA compared with non-RA (RA × follow-up year, β 0.21, 95% CI 0.20 to 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 patients with RA than in patients without RA during and immediately following RA onset. Therefore, multimorbidity should be aggressively identified and targeted early in the RA disease course.
- outcome assessment
- health care
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Handling editor Josef S Smolen
Presented at This work was previously presented in abstract form at the 2019 American College of Rheumatology Annual Meeting: BRE, PR, FY, HS, KM, FX, JRC, TRM. Trajectory of multimorbidity in rheumatoid arthritis in a US commercial insurance claims database from 2006–2015. Arthritis Rheumatol 2019; 71 (suppl): Abstract 840.
Contributors BRE, TRM and JRC designed the study. FX and JRC were responsible for acquisition of data. BRE, PR, YY and HS analysed the data. All authors were responsible for interpretation of the data and for drafting, revising and approving the final submitted manuscript.
Funding This work was supported by the Rheumatology Research Foundation Scientist Development Award (BRE), Great Plains IDeA-CTR Scholars Award (BRE) and Patient-Centered Outcomes Research Institute (JRC). TRM is supported by the NIH/NIGMS (U54GM115458) and NIAAA (R25AA020818).
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Patient consent for publication Not required.
Ethics approval This study was reviewed by the institutional review boards at the University of Nebraska Medical Center and University of Alabama at Birmingham.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request and ethical approval.
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