How Does Race and Ethnicity Impact Multimorbidity in RA?

Researchers identified differences in multimorbidity and individual comorbidities among patients with rheumatoid arthritis, based on race and ethnicity.

Multimorbidity is more common among individuals with vs without rheumatoid arthritis (RA), regardless of race and ethnicity; however, some individual comorbidities occur more frequently in patients with RA of certain races and ethnicities, according to study findings published in Arthritis Care & Research (Hoboken).

Previous studies have indicated that multiple comorbidities often correspond to poorer quality of life, higher mortality, and decreased physical functioning.

To determine the effect of race and ethnicity on multimorbidity in RA, researchers conducted a case-control study between 2010 and 2019 using deidentified data from OptumLabs Data Warehouse®. Patients with RA were matched, based on sex, race and ethnicity, region, index date of RA, and insurance coverage duration, with control participants without RA.

Multimorbidity was defined as the presence of at least 2 or at least 5 validated comorbidities.

Compared with those in the control group, patients in the RA group across all races and ethnicities had increased risk for at least 2 and at least 5 comorbidities (adjusted odds ratio [aOR], 2.19; 95% CI, 2.16-2.23 and aOR, 2.06; 95% CI, 2.02-2.09, respectively).

The researchers observed that Black patients had the most multimorbidity (73.1% with ≥2 and 34.3% with ≥5 comorbidities) and those of Asian descent had the least multimorbidity (52.4% with ≥2 and 17.3% with ≥5 comorbidities).

Anxiety and depression were more likely to occur in patients with RA, regardless of race or ethnicity. However, the highest overall point estimates of anxiety and depression was observed among White patients with RA (7.8% and 11.4%, respectively).

White individuals with vs without RA were also more likely to have renal disease (4.7% vs 3.2%, respectively; P <.001). Both White and Black individuals with vs without RA were more likely to have valvular heart disease (3.2% vs 2.8% and 2.6% vs 2.2%, respectively; all P <.001).

Study limitations included lack of generalizability to patients without commercial or Medicare insurance; age younger than 65 years for 61% of participants, which may have restricted detection of differences in multimorbidity in other age groups; the possible misclassification of RA and comorbidities; health care utilization bias; and potential confounding due to unexamined factors.

“Multimorbidity is a problem for all patients [with RA],” the study authors said. “Targeted identification of certain comorbidities by race and ethnicity may be a helpful approach to mitigate multimorbidity.”


Kronzer VL, Dykhoff HJ, Stevens MA, Myasoedova E, Davis JM, Crowson CS. Racial differences in multimorbidity and comorbidities in rheumatoid arthritis. Arthritis Care Res (Hoboken). Published online September 12, 2022. doi:10.1002/acr.25020