Hypertension related to HAART in HIV-positive women

A poster reporting data from the US Women’s interagency HIV study (WIHS), an ongoing, prospective, multi site cohort study of HIV positive and at risk HIV negative women, evaluated the occurrence of hypertension and its association with HAART. [1]

In this analysis, data from 2,057 HIV-positive and 569 HIV-negative women enrolled in 1994 and 1995 were evaluated. Study visits occurred every six months and the evaluations were performed at visit 16.

Hypertension was defined as elevated diastolic blood pressure >90 mmHg or elevated systolic blood pressure >140 mmHg on physical exam during a routine study visit or the taking of antihypertensive medications.

The investigators found the baseline prevalence rate of hypertension to be 19% for both HIV-positive and HIV-negative women. The overall incidence rate was not significantly different between the HIV-positive (47%) and HIV-negative women (46%).

In both univariate and multivariate analyses they reported: increasing age, African American race, lower education level, smoking, increasing body mass index (30+), and use of HAART (RR 1.26, 95% CI: 1.10 to 1.48, p=0.01) to be significantly associated with hypertension. They also found that both current pregnancy, and AZT monotherapy (RR 0.50, 95% CI: 0.35 to 0.72, p=0.0001) offered protection from hypertension.

Lower CD4 count and higher viral load were associated with a reduced risk in univariate analysis for developing hypertension, although neither was found to be significant in multivariate analysis. The investigators also reported a time-dependent relationship between duration of therapy and hypertension (RR 1.32, 95% CI: 1.11 to 1.58, p=0.02 for one six-month interval on HAART; RR 1.36, 95% CI: 1.12 to 1.65, p=0.02 for 12 months; and RR 1.51, 95% CI: 1.30 to 1.75, p<0.0001, for more than 18 months on HAART).

The investigators concluded that after controlling for risk factors such as age, race and body mass index an increased RR of developing hypertension was found in HIV-positive women on increasing duration of HAART. However, they reported that this did not correspond with the overall incidence rate or with incidence across visits in which no difference was found between the HIV-positive women receiving and not receiving HAART, nor between the HIV-positive women and at risk HIV-negative women. They also noted a possible protective use of AZT monotherapy although not AZT as part of a HAART regimen.

Comment

One interpretation of these data could be that treating HIV infection restores the normal risk of hypertension. There was also informal discussion of this as a possible explanation for reported pre-eclampsia in pregnancy and HAART. [2]

The mechanism is obscure but then so is the cause of essential hypertension but perhaps some involvement of the immune system is needed for essential hypertension as it is for pre-eclampsia.