Incidence and risk factors for hypertension among HIV patients in rural Tanzania - A prospective cohort study

Abstract

Introduction: Scarce data are available on the epidemiology of hypertension among HIV patients in rural sub-Saharan Africa. We explored the prevalence, incidence and risk factors for incident hypertension among patients who were enrolled in a rural HIV cohort in Tanzania.

Methods: Prospective longitudinal study including HIV patients enrolled in the Kilombero and Ulanga Antiretroviral Cohort between 2013 and 2015. Non-ART naïve subjects at baseline and pregnant women during follow-up were excluded from the analysis. Incident hypertension was defined as systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg on two consecutive visits. Cox proportional hazards models were used to assess the association of baseline characteristics and incident hypertension.

Results: Among 955 ART-naïve, eligible subjects, 111 (11.6%) were hypertensive at recruitment. Ten women were excluded due to pregnancy. The remaining 834 individuals contributed 7967 person-months to follow-up (median 231 days, IQR 119-421) and 80 (9.6%) of them developed hypertension during a median follow-up of 144 days from time of enrolment into the cohort [incidence rate 120.0 cases/1000 person-years, 95% confidence interval (CI) 97.2-150.0]. ART was started in 630 (75.5%) patients, with a median follow-up on ART of 7 months (IQR 4-14). Cox regression models identified age [adjusted hazard ratio (aHR) 1.34 per 10 years increase, 95% CI 1.07-1.68, p = 0.010], body mass index (aHR per 5 kg/m2 1.45, 95% CI 1.07-1.99, p = 0.018) and estimated glomerular filtration rate (aHR < 60 versus ≥ 60 ml/min/1.73 m2 3.79, 95% CI 1.60-8.99, p = 0.003) as independent risk factors for hypertension development.

Conclusions: The prevalence and incidence of hypertension were high in our cohort. Traditional cardiovascular risk factors predicted incident hypertension, but no association was observed with immunological or ART status. These data support the implementation of routine hypertension screening and integrated management into HIV programmes in rural sub-Saharan Africa.

Fig 1. Patient flow chart.

Fig 2. Kaplan-Meier survival estimates of hypertension development according to the independent risk factors at baseline: age (left), body mass index (centre) and estimated glomerular filtration rate (right).

BMI: body mass index; eGFR: estimated glomerular filtration rate.