Hypertension, kidney disease, HIV and antiretroviral therapy among Tanzanian adults: a cross-sectional study

Background: The epidemics of HIV and hypertension are converging in sub-Saharan Africa. Due to antiretroviral therapy (ART), more HIV-infected adults are living longer and gaining weight, putting them at greater risk for hypertension and kidney disease. The relationship between hypertension, kidney disease and long-term ART among African adults, though, remains poorly defined. Therefore, we determined the prevalences of hypertension and kidney disease in HIV-infected adults (ART-naive and on ART >2 years) compared to HIV-negative adults. We hypothesized that there would be a higher hypertension prevalence among HIV-infected adults on ART, even after adjusting for age and adiposity. Methods: In this cross-sectional study conducted between October 2012 and April 2013, consecutive adults (>18 years old) attending an HIV clinic in Tanzania were enrolled in three groups: 1) HIV-negative controls, 2) HIV-infected, ART-naive, and 3) HIV-infected on ART for >2 years. The main study outcomes were hypertension and kidney disease (both defined by international guidelines). We compared hypertension prevalence between each HIV group versus the control group by Fisher's exact test. Logistic regression was used to determine if differences in hypertension prevalence were fully explained by confounding. Results: Among HIV-negative adults, 25/153 (16.3%) had hypertension (similar to recent community survey data). HIV-infected adults on ART had a higher prevalence of hypertension (43/150 (28.7%), P = 0.01) and a higher odds of hypertension even after adjustment (odds ratio (OR) = 2.19 (1.18 to 4.05), P = 0.01 in the best model). HIV-infected, ART-naive adults had a lower prevalence of hypertension (8/151 (5.3%), P = 0.003) and a lower odds of hypertension after adjustment (OR = 0.35 (0.15 to 0.84), P = 0.02 in the best model). Awareness of hypertension was <= 25% among hypertensive adults in all three groups. Kidney disease was common in all three groups (25.6% to 41.3%) and strongly associated with hypertension (P < 0.001 for trend); among hypertensive participants, 50/76 (65.8%) had microalbuminuria and 20/76 (26.3%) had an estimated glomerular filtration rate (eGFR) < 60 versus 33/184 (17.9%) and 16/184 (8.7%) participants with normal blood pressure. Conclusions: HIV-infected adults on ART > 2 years had two-fold greater odds of hypertension than HIV-negative controls. HIV-infected adults with hypertension were rarely aware of their diagnosis but often have evidence of kidney disease. Intensive hypertension screening and education are needed in HIV-clinics in sub-Saharan Africa. Further studies should determine if chronic, dysregulated inflammation may accelerate hypertension in this population.