Background:  It remains uncertain whether patients with HIV-1 infection are at increased risk for coronary heart disease or myocardial infarction regardless of treatment regimen.  Further follow-up is needed to understand the extent to which atherogenic lipid changes consequent to PI therapy contribute to coronary heart disease and myocardial infarction risk. 

Methods:  We continue to monitor hospitalizations for coronary heart disease (ICD9 410-414, including myocardial infarction) among HIV⁺ males and among a random sample of presumed HIV^- males.  All persons studied were members of the Kaiser Permanente Northern California HMO.  Persons with prior coronary heart disease events were excluded.  Observational follow-up for 80% of HIV⁺ men began in 1996 and now extends through June 30, 2003.  For HIV⁺ men, person-years of follow-up was assigned as either pre/no-PI exposure vs PI exposure.  A person could contribute person-years to both exposure categories.  Age-adjusted coronary heart disease and myocardial infarction rates for ages 35 to 64 were calculated overall for HIV⁺ and HIV^-, and by PI exposure and duration of PI exposure for HIV⁺.  Cox proportional hazards regression was used to assess the relative risk for hospitalization due to HIV infection taking into account traditional risk factors (age, smoking, hypertension, diabetes mellitus, lipids and total cholesterol:HDL ratio), as obtained from electronic medical records. 

Results: In the 7.5-year observation period, 4726 HIV⁺ patients contributed 20,589 person-years of follow-up (median 4.5) and there were 111 coronary heart disease events (66 myocardial infarctions). More than 40,000 HIVsup>-men contributed 256,000 person-years of follow-up.  Among HIV⁺ participants exposed to PI, median PI exposure was 4.0 years.  Age-adjusted coronary heart disease and myocardial infarction rates among HIV⁺ participants continue to be roughly twice that of HIV^-  (coronary heart disease:  6.6 vs 3.0 events/1000 person-years, p <0.0001; myocardial infarction:  3.9 vs 2.2,  p <0.005).  Among HIV⁺ men, overall rates for never vs ever PI exposure were not different (coronary heart disease:  5.6 vs 7.4,  p = 0.21; myocardial infarction:  3.6 vs 4.2,  p = 0.61).  However, the age-adjusted relative risk for coronary heart disease hospitalization per 2 years of PI exposure was 1.17 (95% CI:  1.03, 1.33,  p = 0.01); relative risk for myocardial infarction was 1.07 (0.9, 1.3,  p = 0.41). 

Conclusions:  HIV⁺ persons, even without exposure to PI, have twice the rate of hospital coronary heart disease and myocardial infarction as HIV^- persons and  we continue to examine the effect of traditional risk factors.  Risk of coronary heart disease was associated with duration of PI use, but we were unable to show a similar association with myocardial infarction- possibly due to small numbers; longer follow-up is needed.  Risk reduction management is warranted in all patients with coronary heart disease risks and any risks associated with PI use must be weighed against the known benefits.

Keywords: HIV; coronary heart disease; antiretroviral therapy