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Abacavir use and risk of acute myocardial infarction and cerebrovascular disease in the HAART era
Presented by Roger Bedimo (United States).
R. Bedimo1,2, A. Westfall3, H. Drechsler1,2, P. Tebas4
1VA North Texas Healthcare System, Medicine, Dallas, United States, 2University of Texas Southwestern Medical Center, Medicine, Dallas, United States, 3University of Alabama at Birmingham, Medicine, Birmingham, United States, 4University of Pennsylvania, Medicine, Philadelphia, United States
Background: Exposure to abacavir (ABC) has recently been associated with an increased risk of acute myocardial infarction (AMI).
Methods: Patients with AMI and cerebrovascular accidents (CVA) episodes were identified by ICD9 code in the Veterans Administration's Clinical Case Registry. We classified patients followed in the HAART era (1996-2004) according to their antiretroviral (ART) use prior to the AMI or CVA event: on HAART (receiving ≥ 3 antiretrovirals) containing ABC, on HAART with other NRTI, on non-HAART ART, and not on ART. We then performed survival analyses (Cox Proportional Hazard model) to predict incident AMI and CVA, exploring ART as a time-dependent variable.
Results: 19,424 HIV-infected patients contributed 75,311 patient-years (PY) of follow-up in the HAART era (median follow-up = 3.88 years). 278 AMI and 868 CVA were diagnosed. Rates of AMI (per 1000 patient-years) were: 3.69; 5.92 for patients on HAART with ABC (3,884 PY contributed); 4.18 for patients on HAART with other NRTIs (25,094 PY); 4.66 for patients on Non-HAART ART (6,647 PY); and 2.98 for patients not receiving ART (39,562 PY). Each year of ABC use was associated with an unadjusted hazard ratio (HR) of AMI of 1.27 (95% CI: 0.99 - 1.62; p = 0.057) and HR of CVA of 1.17 (CI: 0.98 - 1.39; p = 0.081). After adjusting for age, hyperlipidemia, diagnoses of hypertension (HTN), type 2 diabetes (DM), and smoking status, HR for ABC use was 1.18 (95% CI: 0.92 - 1.50; p = 0.191) for AMI and 1.16 (0.98 - 1.37; p = 0.096) for CVA.
Conclusions: In our cohort, cumulative exposure to ABC was associated with a modest, non-statistically significant increase in AMI and CVA risks. The association of ABC use with AMI was much weaker after adjusting for traditional cardiovascular risk factors. The AMI risk appears to be lowest for patients not receiving ART.
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