Comparison of Ischemic Stroke Incidence in HIV-Infected and Non-HIV-Infected Patients in a US Health Care System

Background: Cardiovascular disease is increased among HIV-infected patients, but little is known regarding ischemic stroke rates. We sought to compare stroke rates and determine stroke risk factors in HIV-infected versus non-HIV-infected patients. Methods: An HIV cohort and matched non-HIV comparator cohort seen between 1996 and 2009 were identified from a Boston health care system. The primary endpoint was ischemic stroke, defined using International Classification of Diseases (ICD) codes. Unadjusted stroke incidence rates were calculated. Cox proportional hazards modeling was used to determine adjusted hazard ratios (HRs). Results: The incidence rate of ischemic stroke was 5.27 per 1000 person-years in HIV-infected compared with 3.75 in non-HIV-infected patients, with an unadjusted HR of 1.40 [95% confidence interval (CI): 1.17 to 1.69, P, 0.001]. HIV remained an independent predictor of stroke after controlling for demographics and stroke risk factors (HR: 1.21, 95% CI: 1.01 to 1.46, P = 0.043). The relative increase in stroke rates (HIV vs. non-HIV) was significantly higher in younger HIV patients (incidence rate ratio: 4.42, 95% CI: 1.56 to 11.09, age 18-29; 2.96, 1.69-4.96, age: 30-39; 1.53, 1.06-2.17, age: 40-49), and in women [HR: 2.16 (95% CI: 1.53 to 3.04) for women vs. HR: 1.18 (95% CI: 0.95 to 1.47) for men]. Among HIV patients, increased HIV RNA (HR: 1.10, 95% CI: 1.04 to 1.17, P = 0.001) was associated with an increased risk of stroke. Conclusions: Stroke rates were increased among HIV-infected patients, independent of common stroke risk factors, particularly among young patients and women.