Background: HIV-infected persons may be at increased risk for cardiovascular disease (CVD) and MI, but the role of HIV in the pathogenesis of MI is unclear. The Universal Definition of MI (UDMI) classifies MIs by underlying pathophysiology into classic primary (type 1) MIs due to atherothrombotic coronary plaque rupture and secondary (type 2) MIs resulting from supply-demand mismatch caused by a heterogeneous set of clinical conditions including sepsis and cocaine-induced vasospasm. In the general population, primary MIs are more common than secondary MIs. Prior studies in HIV have not classified the type of MI and therefore, have examined primary and secondary MIs as a single endpoint, which may limit their ability to define the contribution of HIV to CVD and primary MI risk. We determined the incidence of adjudicated primary MIs distinct from secondary MIs and examined baseline risk factors for primary MIs.
Methods: MIs were centrally adjudicated in 7 NA-ACCORD clinical cohorts between 1996-2010 in patients who screened positive and classified according to the UDMI; primary events included invasive cardiac interventions (CABG, stent placement). Incidence rates (IRs) per 1,000 person-years (PY), adjusted incidence rate ratios (aIRRs), and 95% confidence intervals ([,]) were estimated using Poisson regression adjusted at baseline for sex, race/ethnicity, HIV risk group, year of enrollment, cohort, ever smoked, hypertension (HTN), diabetes (DM), dyslipidemia, chronic kidney disease (CKD), CD4 count, and HIV RNA (viral load); age was time-updated.
Results: There were 24,919 patients who experienced 262 primary and 205 secondary MIs in 95,728 PYs of follow-up: primary MI IR=2.74 [2.42, 3.09] and secondary MI IR=2.14 [1.87, 2.46]. Significant predictors of primary MI included age, HTN, DM, dyslipidemia, smoking, stage 4/5 CKD, and CD4 count (Table 1). Sepsis (33%), cocaine (8%), respiratory failure (5%), and hypertensive emergency (4%) combined accounted for 50% of all secondary MIs.
Conclusions: Traditional CVD risk factors and immunosuppression significantly predict primary MIs. The high rate of secondary MIs emphasizes the need for greater clarity in outcome ascertainment in studies seeking to study the pathogenic role of HIV in CVD. Future analyses will examine the complex longitudinal relationship between primary MIs and HIV-specific factors including CD4 count, viral load, and ART.