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CROI 2012: Elevated Blood Pressure Linked to Heart Attack Risk in HIV+ People

HIV positive people with elevated blood pressure are at higher risk for myocardial infarction, or heart attack, even if they do not meet the definition for high blood pressure, researchers reported at the 19th Conference on Retroviruses and Opportunistic Infections (CROI 2012) this month in Seattle.

Several observational studies have shown that people with HIV have higher rates of cardiovascular events such as heart attacks and strokes, but it is not yet clear whether this is attributable to long-term viral infection, chronic inflammation, antiretroviral drugs, traditional risk factors, or some combination. Hypertension, or high blood pressure -- along with insulin resistance, abnormal blood lipids, and abdominal obesity -- is a component of metabolic syndrome, which is associated with cardiovascular disease.

Given that HIV and hypertension both raise the risk for myocardial infarction (MI), Kaku Armah from the University of Pittsburgh and fellow investigators with the VACS Project Team investigated whether the association between blood pressure and risk for acute MI differed based on to HIV status.

The researchers analyzed data from 82,490 participants in the observational Veterans Aging Cohort Study Virtual Cohort (VACS VC) who did not have cardiovascular diseases at baseline. 27,365 HIV positive veterans were matched 2:1 with 55,125 HIV negative veterans according to age, sex, race/ethnicity, and clinic site.

Armah and his team looked at incidence of clinically confirmed fatal or non-fatal acute MIs between October 2003 and September 2008 as part of the VA Ischemic Heart Disease Quality Enhancement Research Initiative. They collected data on systolic and diastolic blood pressure (the top and bottom numbers, respectively), use of anti-hypertension medications, diabetes, abnormal lipids, and other cardiovascular risk factors at baseline.

A blood pressure reading below 120/80 is considered normal, 120-139/80-90 is pre-hypertension, 140-159/90-99 is stage 1 hypertension, and above 160/100 is stage 2 hypertension. This study divided participants into 4 categories: less than <120/<80, 120-139/80-89 with no blood pressure medications, <140/<90 with medications, and >140/>90 with or without medications.

Results

• Over 5 years of follow-up, about half of all reported acute MIs occurred in people with HIV, even though they accounted for one-third of the study population.
• HIV positive people had more acute MIs than HIV negative people in all blood pressure categories.
• The difference between HIV positive and HIV negative acute MI rates was minimal among people with normal systolic blood pressure, and greatest among those in the 2 highest categories.
• A similar pattern was observed for diastolic blood pressure, but the difference in MI rates in the highest categories was even larger.
• Compared with the acute MI rate for HIV negative people with normal systolic blood pressure (designated 1.0), hazard ratios for negative people were 1.1 if 120-139, 1.5 if <140 on meds, and 1.6 if >140; for HIV positive people the corresponding rates were 1.2, 1.7, 2.2, and 2.4, respectively.
• Compared with the acute MI rate for HIV negative people with normal diastolic blood pressure (again 1.0), rates for negative people were 1.3 if 120-139, 1.5 if <140 on meds, and 1.7 if >140; for HIV positive people the corresponding rates were 1.3, 1.9, 2.2, and 3.0, respectively.

"Systolic and diastolic hypertension are associated with increased acute MI risk" in HIV positive people, the researchers concluded. "Increased acute MI risk is present even at pre-hypertensive levels."

Based on these findings, they recommended that clinicians treat high blood pressure in HIV positive patients. Lifestyle modification to address pre-hypertension is also advised to prevent progression to hypertension.

3/27/2012

Reference

K Armah, A Justice, K Oursler, et al. The Impact of Elevated and Pre-hypertensive Systolic Blood Pressure and the Risk of Acute Myocardial Infarction in HIV+ and HIV- Veterans. 19th Conference on Retroviruses and Opportunistic Infections (CROI 2012). Seattle, WA. March 5-8, 2012. Abstract 120.