CHICAGO – Comorbidities increase disease activity regardless of race/ethnicity or medication use among patients with rheumatoid arthritis, although black patients are more likely to experience comorbidities and less likely to achieve remission, according to findings presented at the ACR/ARHP 2018 Annual Meeting.
“Racial/ethnic disparities in comorbidity in RA may confound treatment and outcomes,” the researchers wrote. “[The] Rheumatic Disease Comorbidity Index is a validated tool predicting disability and mortality in patients [with RA]. We evaluated the association between [the Rheumatic Disease Comorbidity Index] and clinical outcomes within racial/ethnic subsets of RA patients.”
Sharon Dowell, MD, assistant professor of medicine in the division of rheumatology and attending physician at Howard University College of Medicine and Howard University Hospital, and colleagues evaluated patients enrolled in the Ethnic Minority RA Consortium with at least one follow-up visit. The Rheumatic Disease Comorbidity Index was produced using enrollment data.
Clinical outcomes included tender joint count, swollen joint count, and RAPID3 and DAS28 scores. Medication use was aggregated and recorded as prednisone/methotrexate, other disease-modifying antirheumatic drugs, and biologics. Enrollment differences between racial/ethnic groups were estimated.
The researchers then calculated changes in racial/ethnic groups during follow-up. Associations between Rheumatic Disease Comorbidity Index scores and clinical outcomes and remission, which was classified as a DAS28 score of less than 2.6, were also evaluated. Adjustments were made to consider enrolment age, gender, education, race/ethnicity and medication use.
The researchers analyzed 1,066 patients with 3,719 follow-up visits through 58 weeks. Racial disparities were identified in formal education, RAPID3 scores, DAS28 scores, tender joint count, swollen joint count, comorbidity, medication use and length of follow-up.
After adjustments for age, education, gender and race/ethnicity, increases in Rheumatic Disease Comorbidity Index scores correlated with higher scores at the time of enrollment for RAPID3 (P = .022) and DAS28 (P < .001). DAS28 scores at the time of enrollment were significantly higher among black (0.49; 95% Cl, 0.21-0.78) and Hispanic individuals (0.70; 95% Cl, 0.37-1.03) than whites.
Although increased Rheumatic Disease Comorbidity Index scores limited improvement in RAPID3 (P < .001), and DAS28 (P < .001) scores, Rheumatic Disease Comorbidity Index scores did not correlate with decreased odds of DAS28 remission. Black individuals were significantly less likely to achieve DAS28 remission than any other racial/ethnic subset. Biologic use was found to increase the odds of DAS28 remission (OR = 1.53; 95% Cl, 1.01-2.33), although that association decreased with “advanced” age (OR = 0.80, 95% CI, 0.68-0.95), according to the findings.
“Comorbidity was associated with higher disease activity regardless of race/ethnicity or medication, with black patients having more comorbidity and less odds of remission,” the researchers wrote. “Early access to care for management of comorbidities and disease in black patients [with RA] is necessary to improve outcomes.” – by Erin Michael
Reference: Dowell S, et al. Abstract 881. Presented at: 2018 ACR/ARHP Annual Meeting, Oct. 20-24, 2018; Chicago.
Disclosures: Dowell reports associations with Bristol-Myers Squibb, Pfizer, Genetech and Horizon Pharma. Please see the abstract for all other authors’ relevant financial disclosures.