Background: Previous studies of HIV-infected patients show significant associations of highly active antiretroviral therapy (HAART) with worsening blood pressure and blood glucose levels; however, the mechanisms involved are less clear. Therefore, we sought to investigate the potential mediating effects of body fat changes on HAART-associated increases in blood pressure and blood glucose levels among people living with HIV.
Methods: Four Hundred and Six consenting patients (≥ 18 years) attending a tertiary HIV clinic in semi-urban Nigeria were recruited between August and November 2014 as part of a cross-sectional study. We performed bias-corrected bootstrap tests of mediation using 95% confidence intervals (CI) to determine the mediating effects of body mass index and waist circumference (mediators) on the total effects of HAART exposure (primary predictor) on blood pressure and blood glucose levels (outcomes), while adjusting for potential confounders including age, sex, smoking status, CD4 cell count and duration of HIV infection.
Results: Waist circumference remained a significant partial mediator of the total effects of HAART exposure on increasing systolic blood pressure (coefficient: 1.01, 95% CI 0.33 to 2.52, 11% mediated), diastolic blood pressure (coefficient: 0.68, 95% CI 0.26 to 1.89, 9% mediated) and blood glucose levels (coefficient: 0.67, 95% CI 0.14 to 1.67, 25% mediated) after adjusting for all potential confounders; whereas, no significant mediating effect was observed with body mass index or combined body mass index/waist circumference.
Conclusion: Our findings suggest that body fat, especially central fat accumulation, may mediate HAART-associated increases in blood pressure and blood glucose levels among HIV-infected patients, independent of the role of traditional risk factors. The use of waist circumference as a complementary measure of body fat to body mass index may improve the clinical prediction of hypertension and diabetes among HIV-infected patients on antiretroviral therapy.