Abacavir and risk of myocardial infarction in HIV‐infected patients on highly active antiretroviral therapy: a population‐based nationwide cohort study

• Published in: HIV medicine Vol. 11; no. 2; pp. 130 - 136
• Main Authors: Obel, N, Farkas, DK, Kronborg, G, Larsen, CS, Pedersen, G, Riis, A, Pedersen, C, Gerstoft, J, Sørensen, HT
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.02.2010
• Subjects: Abacavir; Adult; Anti-HIV Agents - adverse effects; Antiretroviral Therapy, Highly Active; Comorbidity; Data processing; Denmark - epidemiology; Dideoxynucleosides - adverse effects; Epidemiologic Methods; Female; highly active antiretroviral therapy; HIV; HIV Infections - drug therapy; Hospitalization - statistics & numerical data; Human immunodeficiency virus; Humans; ischemic heart disease; Male; Middle Aged; Myocardial infarction; Myocardial Infarction - chemically induced; Myocardial Infarction - epidemiology; Myocardial Ischemia - epidemiology; nucleoside reverse transcriptase inhibitors; nucleotide analogues; Proportional Hazards Models; Risk assessment; Time Factors; Denmark
• ISSN: 1464-2662; 1468-1293
• DOI: 10.1111/j.1468-1293.2009.00751.x

Objective The aim of the study was to examine whether exposure to abacavir increases the risk for myocardial infarction (MI). Design, setting and subjects This was a prospective nationwide cohort study which included all Danish HIV‐infected patients on highly active antiretroviral therapy (HAART) from 1995 to 2005 (N=2952). Data on hospitalization for MI and comorbidity were obtained from Danish medical databases. Hospitalization rates for MI after HAART initiation were calculated for patients who used abacavir and those who did not. We used Cox's regression to compute incidence rate ratios (IRR) as a measure of relative risk for MI, while controlling for potential confounders (as separate variables and via propensity score) including comorbidity. Main outcome Relative risk of hospitalization with MI in abacavir users compared with abacavir nonusers. Results Hospitalization rates for MI were 2.4/1000 person‐years (PYR) [95% confidence interval (CI) 1.7–3.4] for abacavir nonusers and 5.7/1000 PYR (95% CI 4.1–7.9) for abacavir users. The risk of MI increased after initiation of abacavir [unadjusted IRR=2.22 (95% CI 1.31–3.76); IRR adjusted for confounders=2.00 (95% CI 1.10–3.64); IRR adjusted for propensity score=2.00 (95% CI 1.07–3.76)]. This effect was also observed among patients initiating abacavir within 2 years after the start of HAART and among patients who started abacavir as part of a triple nucleoside reverse transcriptase inhibitor (NRTI) regimen. Conclusions We confirmed the association between abacavir use and increased risk of MI. Further studies are needed to control for potential confounding not measured in research to date.