Background:  Evidence mounts that HIV-infected patients are at increased risk of vascular morbidities, particularly myocardial infarction (MI). In Kaiser Permanente and elsewhere, risk factor modification has become a priority. Ongoing and timely vascular event surveillance in HIV⁺ patients relative to HIV^– patients is of epidemiologic and clinical interest. 

Methods:  We identified adult HIV⁺ members in Kaiser Permanente California, a large integrated health system caring for >6 million Californians, and matched them to HIV^– members (10:1 ratio) on age, sex, and year enrolled in the cohort. We identified hospitalizations for MI (International Classification of Diseases, 9th Revision [ICD-9] 410.x), coronary heart disease (CHD, ICD-9, 410 to 414), peripheral vascular disease (PVD, ICD-9, 443.9), and cerebral vascular (CVD, ICD-9, 433 to 437) diseases. Follow-up extended from first active membership (1996 and after) until the earliest of hospitalization, last health plan enrollment, or June 30, 2008. Crude event rates and relative rates (RR, HIV⁺ vs HIV^–) were estimated for 6 2-year periods from 1996 to June, 2008.

Results:  We examined data on 20,178 HIV⁺ and 202,723 HIV^– patients (89,310 and 1,066,824 person-years, respectively). In unadjusted data over 1996 to 2008, the HIV⁺ MI rate was 2.9 per 1000 person-years (254 MI, 95%CI 2.5 to 3.3) vs 1.6 (1029 MI, 95%CI 1.5 to 1.7) among HIV^–. HIV⁺ patients had 1.4x higher rates of both CHD and CHD+PVD+CVD events combined, compared to HIV^– (p <0.001). Crude HIV+ MI rates for the 6 2-year periods were 2.2, 3.1, 2.7, 3.7, 3.1, and 2.4 per 1000 person-years, suggesting a decline since 2002. Similarly, the RR of HIV⁺ vs HIV^– for MI became only borderline significant at 1.3 (p = 0.062) in 2006 to 2008 (see table).

Conclusions:  In a much larger cohort we continue to observe an increased risk of cardiovascular events with HIV infection in the HAART era. However, recent MI rates among our HIV patients are approaching background levels, perhaps reflecting better risk factor modification including the use of less atherogenic medications. Continued surveillance is warranted.