Myocardial infarction in ANCA-associated vasculitis: A population-based cohort study

Objectives To determine the incidence rate (IR) and predictors of myocardial infarction (MI) in patients with antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) as well as to estimate the IR ratio (IRR) of MI in AAV versus the background population. Methods 325 patients diagnosed with AAV 1997-2016 in Skåne, Sweden were included. Data were collected from the time of AAV diagnosis, and each patient was grouped with 10 age-matched and sex-matched reference subjects from the background population. MI after AAV diagnosis was identified using Swedish Web-System for Enhancement and Development of Evidence-based Care in Heart Disease Evaluated According to Recommended Therapies and the Skåne Healthcare Register, and IR of first MI calculated. The IRR was computed by dividing the IR for 282 AAV patients by the corresponding rate in the 2763 reference subjects. Predictors of MI were analysed using Cox regression. Results 37 patients (11%) with AAV suffered an initial MI, yielding an IR of 1.6/100 person-years of follow-up (95% CI 1.2 to 2.2). The highest rate was recorded in the 3 months following AAV diagnosis, at 11.8/100 person-years (95% CI 6.2 to 22.7). The IRR of MI in AAV/reference was 1.9 (95% CI 1.3 to 2.8), highest in patients with myeloperoxidase-ANCA+disease (IRR 2.5, 95% CI 1.5 to 4.3) and those with high disease activity at diagnosis (2.1, 95% CI 1.3 to 3.3). Age at AAV diagnosis independently predicted MI. Conclusions The MI IR is greater in individuals diagnosed with AAV compared with background population, especially those with more severe disease, and highest in the 3 months following diagnosis. Age at diagnosis is the single independent predictor of MI in AAV in this study.