Converging epidemics of HIV and hypertension in Africa

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

Peck RN, Shedafa R, Kalluvya S, Downs JA, Todd J, Suthanthiran M, Fitzgerald DW, Kataraihya JB. BMC Med. 2014 Jul 29;12(1):125. [Epub ahead of print]

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.

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Editor’s notes: The prevalence of both hypertension and HIV in sub-Saharan Africa is the highest among any region in the world. Hypertension is a leading risk factor for disease and accounts for nearly 10 million deaths a year. As antiretroviral therapy (ART) coverage has increased, infection-related mortality rates have substantially declined. Increased life-expectancy and weight gain among people taking ART may “unmask” an epidemic of hypertension in sub-Saharan Africa, where, unlike other global regions, the blood pressure of adults continues to rise.

This study showed a high prevalence of hypertension among HIV-positive adults taking ART for two or more years. The prevalence was nearly double that among HIV-negative adults, even after adjusting for age, sex and adiposity. In contrast, the prevalence of hypertension among ART-naïve adults was significantly lower than that among HIV-negative adults. There was no association between use of the first line antiretroviral drugs and hypertension, suggesting that the high prevalence of drugs cannot be explained by the type of drugs used to treat HIV infection.

Of concern, only 25% of hypertensive adults were aware of their condition. Among HIV-positive adults on ART, some 75% of those with hypertension were undiagnosed, some 85% were untreated and more than 95% were uncontrolled. Importantly, hypertension was strongly associated with kidney disease. Given that this is a cross-sectional study, it is not clear whether hypertension preceded kidney disease or vice versa.

Given the high prevalence of hypertension among HIV-positive peoples and that HIV is now a treatable, chronic condition, HIV care provides an opportunity for management of hypertension and should be considered as an integral aspect of HIV care. Studies are needed to understand the role of HIV and ART in causing hypertension, so that appropriate management strategies can be developed.

Comorbidity, HIV Treatment
United Republic of Tanzania
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