Rheumatoid arthritis (RA) is known to be associated with an increased risk of comorbidities, premature mortality, and disability. We investigated the prevalence of comorbidities in RA compared with non-RA controls and the effect of comorbidities on health-related quality of life (HRQoL) and total healthcare expenditures.
Adult RA patients and age-, sex-matched individuals without RA (non-RA controls) were identified from the Medical Expenditure Panel Survey 2010-2015 data. Twenty comorbidities were investigated including cardiovascular, psychological, respiratory, and musculoskeletal conditions. The Short Form-12 physical and mental component summary scores for HRQoL and total healthcare expenditures (2015 US dollars) were summarized based on the number of comorbidities as well as the type of comorbidities. Outcomes were further investigated using multivariable regression analyses.
A total of 2925 patients with RA and 14,625 non-RA controls were included. Approximately 60.4% of RA and 37.2% of non-RA controls had ≥ 3 comorbidities, and 23.5% of RA and 12.0% of non-RA controls had ≥ 5 comorbidities. The prevalence of comorbidities in RA was higher across different types of comorbidities compared with non-RA controls. The most prevalent comorbidities in RA were cardiovascular diseases (79.0%) followed by respiratory conditions (34.4%). Having ≥ 5 comorbidities in RA was significantly associated with lower SF-12 physical and mental scores and increase in healthcare expenditures compared with RA without any comorbidity ($23,214 ($19,941-$26,119) for ≥ 5 comorbidities vs. $11,137 ($7610-$14,396) for no comorbidity).
A substantial number of patients with RA had multiple comorbidities. The comorbidities in RA were associated with poor HRQoL and higher healthcare expenditures. Key Points • The prevalence of comorbidities was significantly higher in RA compared to age- and sex-matched non-RA controls. • RA itself was associated with lower mental and physical health-related quality of life and increase in healthcare expenditures. • A higher number of comorbidities in RA were associated with poorer mental and physical health-related quality of life and increase in healthcare expenditures. • Specific comorbidities such as respiratory conditions and psychological disorders were associated with both health-related quality of life and economic burden in RA.