Abstract 057: Increased Incidence of Ischemic Stroke in HIV-Infected Women in a Clinical Care Cohort
Introduction: Coronary heart disease rates are increased among HIV-infected patients compared to control groups, with a relatively greater increase in women compared to men. Whether a similar pattern with respect to gender is true for ischemic stroke is not known. We assessed the hypothesis that the adjusted hazard ratio for ischemic stroke given HIV infection is greater among women compared to men.
Methods: The study was conducted using data from an HIV observational clinical care cohort at a large Boston-based health care system. A control cohort of non-HIV-infected patients was matched in a 10:1 ratio to the HIV cohort based on age, gender, and race. The observation period was between 1996 and 2009, with right censoring at the initial stroke event or last encounter if prior to 2009. Ischemic stroke events were identified by pre-specified and validated ICD-9-CM codes. Gender-specific stroke incidence rates were calculated. To assess the association of HIV and ischemic stroke within each gender, Cox proportional hazard modeling was employed.
Results: The cohorts consisted of 4,308 HIV-infected patients (31% women) and 32,423 non-HIV-infected patients (35% women). Among women, ischemic stroke event rates were 5.02 per 1000 person years (PY) in HIV-infected versus 2.31 per 1000 PY in non-HIV-infected patients (40 events in HIV and 177 events in non-HIV) with an unadjusted hazard ratio (HR) of 2.16 (95% confidence interval [CI] 1.53–3.04, P<0.001). In contrast, among men ischemic stroke rates were 5.38 per 1000 PY in HIV-infected versus 4.59 per 1000 PY in non-HIV-infected patients (92 events in HIV and 605 events in non-HIV patients) with an unadjusted HR of 1.18 (95% CI 0.95–1.47, P=0.14). Comparing HIV-infected to non-HIV-infected patients, incidence rates were significantly increased among women in the 18–29, 30–39, and 40–49 age groups and among men in the 30–39 age group. In a gender-stratified, multivariate regression model adjusting for age, race, hypertension, diabetes, dyslipidemia, smoking, structural heart disease, atrial fibrillation, aspirin use, and warfarin use, the adjusted HR for stroke associated with HIV infection was 1.76 (95% CI 1.24–2.52, P=0.002) among women compared with 1.05 (95% CI 0.84–1.32, P=0.639) among men.
Conclusions: Ischemic stroke incidence rates were significantly increased in HIV-infected patients compared to non-HIV-infected patients among young women (< 50) and a subset of young men. HIV infection remained independently associated with stroke among women after adjusting for demographic and traditional stroke risk factors. While further studies are merited investigating causality and potential mechanisms for stroke among HIV-infected women, this group may represent a uniquely at-risk population for accelerated cerebrovascular aging.
- © 2012 by American Heart Association, Inc.