Abacavir and risk of myocardial infarction in HIV-infected patients on highly active antiretroviral therapy: a population-based nationwide cohort study.
OBJECTIVE
The aim of the study was to examine whether exposure to abacavir increases the risk for myocardial infarction (MI).


METHODS
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.


RESULTS
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.
Obel
Niels
N
Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Denmark. niels.obel@rh.regionh.dk
Farkas
D K
DK
Kronborg
G
G
Larsen
C S
CS
Pedersen
G
G
Riis
A
A
Pedersen
C
C
Gerstoft
J
J
Sørensen
H T
HT
D000328:Adult; D019380:Anti-HIV Agents / Q000009:adverse effects*; D023241:Antiretroviral Therapy, Highly Active; D015897:Comorbidity; D003718:Denmark / Q000453:epidemiology; D015224:Dideoxynucleosides / Q000009:adverse effects*; D004812:Epidemiologic Methods; D005260:Female; D015658:HIV Infections / Q000188:drug therapy*; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000139:chemically induced* / Q000453:epidemiology; D017202:Myocardial Ischemia / Q000453:epidemiology; D016016:Proportional Hazards Models; D013997:Time Factors; D000099227:Abacavir
D019380:Anti-HIV Agents; D015224:Dideoxynucleosides; D000099227:Abacavir