Abstract
INTRODUCTION: Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy; however, they have been associated with clinically significant immune-related adverse events (irAEs), including rheumatic irAEs. Rheumatic irAEs due to ICIs are not well characterized among ethnic minorities. OBJECTIVE: Accordingly, we investigated rheumatic irAEs and referrals to rheumatologists at a public medical center (MC) serving a predominantly Hispanic population and a neighboring private MC serving a predominantly a population that identified as White, Black, Asian, or Indigenous population, with each MC being staffed by faculty from the same medical school. METHODS: The medical records of patients 18+ years seen at either MC from May 2015 through May 2021 were screened for treatment with ICIs by ICD codes. We compared characteristics of ICI-treated patients who developed irAEs vs. those who did not develop irAEs. Overall, 28 (20.9%) and 74 (15.5%) patients developed documented irAEs at the public and private MCs, respectively. Of these, 21 patients (six at the public MC; 15 at the private MC) developed rheumatic irAEs. We compared referral rates to rheumatologists and management of rheumatic irAEs between these two groups. RESULTS: Across both MCs, the most common rheumatic irAEs were arthritis (66.7%) and myositis (14.3%). Compared to private patients, public patients were more likely to be Hispanic (66.7% vs. 13.3%, p=0.012) and less likely to be referred to a rheumatologist (16.7% vs. 66.7%, p=0.036). There were no significant differences between institutions in cancer outcomes in patients with rheumatic iRAEs. CONCLUSION: The significantly lower rate of referrals to rheumatologists among patients with rheumatic irAEs at a public MC compared to patients at a neighboring private MC raises concern for healthcare disparities. Larger studies with racially diverse patients are necessary to help ensure equitable care for all patients.