SEATTLE – Elevated blood pressure may warrant more aggressive management in HIV-positive individuals, suggest results from a cohort study reported at the Conference on Retroviruses and Opportunistic Infections.
In addition, the findings suggest that "we also need to address prehypertension, because we saw an increased risk of AMI [acute myocardial infarction] among prehypertensive people," said Kaku Armah, a doctoral student with the University of Pittsburgh’s Graduate School of Public Health.
"Prehypertension is treated with lifestyle modifications in uninfected people, and we think that should also be used in HIV-infected people," he advised.
He and his colleagues studied 82,490 veterans included in the Veterans Aging Cohort Study–Virtual Cohort, identified HIV-positive patients, and then matched each for age, sex, race/ethnicity, and clinical site to two HIV-negative patients. Blood pressures from the three most recent outpatient visits were averaged to obtain a baseline blood pressure.
All the veterans were free of cardiovascular disease at baseline. During a median 4.6-year follow-up, 443 of them had a fatal or nonfatal acute myocardial infarction (AMI).
Initial analyses showed that within each systolic and diastolic blood pressure bracket, the rate of AMI was consistently higher for the HIV-positive patients than for the HIV-negative patients, although there was some overlap of 95% confidence intervals, Mr. Armah reported.
A first multivariate analysis (adjusted for lipids, smoking, body mass index, comorbidities, and other potential confounders) considered systolic blood pressure, using HIV-negative patients having a value of less than 120 mm Hg and not taking any blood pressure medication as the reference group.
Compared with that group, HIV-positive patients had a significantly elevated risk of AMI if they had a systolic blood pressure of 120-139 mm Hg (prehypertension) and were not taking any medication (hazard ratio, 1.7); had a systolic blood pressure of less than 140 mm Hg and were taking medication (HR, 2.2); or had a systolic blood pressure of 140 mm Hg or greater regardless of medication use (HR, 2.4).
Among HIV-negative patients, the corresponding elevations of AMI risk in these categories were smaller; moreover, the elevated risk was significant only in the group having a systolic blood pressure of 140 mm Hg or greater regardless of medication use (HR, 1.6).
In light of these findings, recommendations for the general population to reduce blood pressure below 140/90 mm Hg may not be sufficient for HIV-positive patients, said Dr. Christopher Nguyen, an internist with the Tom Waddell Health Center in San Francisco. Perhaps HIV-positive patients need to be aiming for targets similar to those used for renal or diabetic patients whose target blood pressure is below 130/80 mm Hg.
The findings were much the same in a second multivariate analysis that instead evaluated AMI risk according to diastolic blood pressure categories.
Mr. Armah said that since the findings are observational, there is not enough evidence yet to recommend such a change in practice.
Session comoderator Caroline Sabin, Ph.D., of University College London inquired about the potential role of antiretroviral therapy, because it has been associated with hypertension and elevated MI rates.
Mr. Armah noted that because the study models included both HIV-positive and HIV-negative patients, it was not possible to adjust for antiretroviral therapy, "but we may do a subset analysis looking at just the HIV-infected people."
In addition, analyses have not yet been done to look at the role of inflammatory markers or the severity of HIV infection in the observed associations.
Mr. Armah reported having no relevant conflicts of interest.