Global cardiovascular risk profiles of untreated hypertensives in an urban, developing community in Africa

Abstract

Introduction

Blood pressure (BP) control in people of African descent is poor, largely because of a lack of treatment. Although the requirements for immediate initiation of antihypertensive drug therapy are defined by global cardiovascular risk, the global cardiovascular risk profiles of untreated hypertensives at a community level are uncertain.

Aim

To identify the distribution of global cardiovascular risk profiles of untreated hypertensives in an urban, developing community of African descent in South Africa.

Methods

As part of the African Programme on Genes in Hypertension, we assessed nurse-derived clinic BP (the mean of five standardised BP values obtained according to guidelines), current antihypertensive therapy, and total cardiovascular risk in 1 029 participants older than 16 years of age from randomly selected nuclear families from the South West Township of Gauteng (SOWETO).

Results

Approximately 46% of participants had systolic/diastolic BP values ≥ 140/90 mmHg and ~23% of participants were hypertensives not receiving antihypertensive medication. Approximately 12% of untreated hypertensives had a high added risk and ~18% a very high added risk (6.7% of the total sample). In untreated hypertensives, in contrast to the absence of severe hypertension and diabetes mellitus in those with lower risk profiles, a high cardiovascular risk profile in this group was characterised by severe hypertension in ~52% and diabetes mellitus in ~33%. Based on a high added risk carrying at least a 20% chance and a very high added risk at least a 30% chance of a cardiovascular event in 10 years, this translates into 1 740 events per 100 000 of the population within 10 years, events that could be prevented through antihypertensive drug therapy.

Conclusions

In an urban, developing community of African ancestry, a significant proportion (6.7%) of people may have untreated hypertension and a global cardiovascular risk profile that suggests a need for antihypertensive drug therapy. Cardiovascular risk in this group is driven largely by the presence of severe hypertension or diabetes mellitus.