Spatial epidemiology of self-reported hypertension in Gauteng province

Abstract

Introduction Hypertension has been identified as a leading cause of morbidity and mortality for cardiovascular-related diseases in sub-Saharan Africa. The aim of this study was to estimate the prevalence, determine factors associated with hypertension and identify the spatial distribution of self-reported hypertension in Gauteng province in South Africa.

Methods The primary study was a cross-sectional household survey done in 2015 by Gauteng City-Region Observatory. Secondary data analysis was done for the study. The primary study population constituted of 30,002 adults aged 18 years or older who resided in Gauteng province. A stratified multistage sampling technique was used in which 508 wards were divided into enumeration areas (EAs) which were the primary sampling units. SaTscan was used to identify significant primary and secondary clusters of people with self-reported hypertension. The prevalence level of self-reported hypertension was estimated as the proportion of respondents in the study who reported that they were hypertensive. Logistic regression was used to model the unadjusted and adjusted association between the hypertension status as an outcome and identified risk factors.

Results The estimated prevalence of self-reported hypertension was 15.5% (n=4,580) in women 16% (n=2,547) and 15% (n=2,033) in men. Factors significantly associated with hypertension in the adjusted model being female (aOR:1.13, 95% CI:1.06-1.21), above 55 years (old age) (aOR:1.17,95% CI:1.01-1.35.), white race (aOR: 2.37, 95% CI: 2.15 -2.62). Residing in formal settlements and renting status of individuals were also significantly associated with hypertension. Five significant spatial clusters of potential hypertension cases were identified in Ekurhuleni municipality

Conclusion The study findings strengthen existing evidence that sex, age, and race are significantly associated with hypertension. The results of the study show that hypertension in Gauteng province is high at 15.5% and it is higher in older females than in males. Public health interventions that target potential clusters or hotspots are recommended.