24-h-Ambulatory Blood Pressure Monitoring in Sub-Saharan Africa: Hypertension Phenotypes and Dipping Patterns in Malawian HIV+ Patients on Antiretroviral Therapy

Abstract

Background: Cardiovascular disease and especially hypertension are a growing problem among people living with HIV (PLHIV) on antiretroviral therapy (ART) in sub-Saharan Africa.

Objectives: As robust data on hypertension phenotypes associated with distinct cardiovascular risks among PLHIV are limited, we aimed to assess the frequency of white-coat (WCH), masked (MH) hypertension, and blood pressure dipping-patterns in a group of Malawian PLHIV.

Methods: As part of the prospective Lighthouse-Tenofovir-Cohort-Study, we analyzed clinical, laboratory and 24-h-ambulatory blood pressure monitoring (ABPM) data of PLHIV from urban Lilongwe with treated or untreated hypertension or raised office blood pressure (OBP) during routine study-visits.

Results: 118 PLHIV were included and data of 117 participants could be analyzed. Twenty-four-hour ABPM normotension was found in a total of 73 PLHIV including 14/37 on antihypertensive treatment (37.8%). Using strict definitions, i.e. normal OBP plus normal mean BP for all periods of ABPM, controlled hypertension was found in only 4/37 (10.8%) PLHIV on antihypertensive treatment while true normotension was observed in 10/24 untreated patients (41.7%) with previously diagnosed hypertension and 22/56 patients (39.3%) without a medical history of hypertension. WCH with normal BP during all periods of 24-h-ABPM was identified in 12/64 OBP-hypertensive PLHIV (18.8%), primarily in patients with grade 1 hypertension (11/41 patients; 26.8%). MH was found in 17/53 PLHIV with OBP-normotension (32.1%), predominantly in patients with high normal BP (11/20 patients; 55%). The estimated glomerular filtration rate tended to be lower in MH compared to strictly defined normotensive PLHIV (92.0±20.4 vs. 104.8±15.7 ml/min/m²). 64.1 percent of PLHIV (59.5% with 24-h hypertension and 66.7% with 24-h normotension) had abnormal systolic dipping.

Conclusion: The high prevalence of WCH and MH with signs of early renal end-organ damage and an abnormal dipping in approximately 2/3 of PLHIV warrants further investigation as these factors may contribute to the increased cardiovascular risk in PLHIV in resource-limited settings like Malawi.

Clinical trial registration: https://clinicaltrials.gov (NCT02381275), registered March 6th, 2015.

Keywords: 24-hour ambulatory blood pressure monitoring; HIV; abnormal blood pressure dipping; masked hypertension; sub-Saharan Africa; white-coat hypertension.

Figure 1

Office blood pressure categories among PLHIV. Optimal OBP (<120/80 mmHg; n = 19); normal OBP (120–129/80–84 mmHg; n = 14); high-normal OBP (130–139/85–89 mmHg; n = 20), grade 1 hypertension (140–159/90–99 mmHg; n = 41), grade 2 hypertension (160-179/100-109 mmHg; n = 14), grade 3 hypertension (≥180/110 mmHg; n = 9). Given are absolute numbers within each OBP category and percentages of masked or white-coat hypertension. HT, hypertension.

Figure 2

Hypertension phenotypes and treatment status. Proportion of patients in each category who did not receive antihypertensive treatment (%). MUCH, masked uncontrolled hypertension; WUCH, white-coat uncontrolled hypertension.