Undiagnosed hypertension in Sudan: results of the cross-sectional national STEPS survey in 2016

Introduction: the rate of hypertension has been increasing in Africa. The study aimed to estimate the prevalence and associated factors of undiagnosed hypertension (HTN) among adults in Sudan. Methods: cross-sectional data were analyzed from 7,226 persons (18-69 years, median 37 years, interquartile range 27-49 years, 4557 were females) who participated in the 2016 Sudan STEPS survey, had complete blood pressure measurement and non-pregnant, and responded to a questionnaire, physical measures, and biomedical tests. Logistic regression was used to determine the predictors of undiagnosed HTN. Results: the prevalence of undiagnosed HTN was 26.2% (n=2057) (79.2% of total HTN), diagnosed HTN 6.9% (n=690) and total HTN 33.1% (n=2747). In multivariable analysis older age (50-69 years) (adjusted risk ratio-aRR: 2.49, 95% CI: 2.02-3.09; p<0.001), obesity (aRR: 2.51, 95% CI: 1.97-3.21; p<0.001), diabetes (aRR: 1.59, 95% CI: 1.17-2.16; p=0.002) and elevated total cholesterol (aRR: 1.48, 95% CI: 1.19-1.84; p<0.001) were positively associated and health care advice (aRR: 0.79, 95% CI: 0.64-0.98; p=0.036) was negatively associated with undiagnosed HTN versus no HTN. Male sex (adjusted odds ratio-aOR: 2.22, 95% CI: 1.63-3.01; p<0.001) was positively associated, and older age (50-69 years) (aOR: 0.31, 95% CI: 0.21-0.46; p<0.001), married (aOR: 0.45, 95% CI: 0.33-0.62; p<0.001), urban residence (aOR: 0.70, 95% CI: 0.51-0.96; p=0.022), health care advice (aOR: 0.32, 95% CI: 0.22-0.45; p<0.001), ever cholesterol measured (aOR: 0.43, 95% CI: 0.27-0.67; p<0.001), overweight (aOR: 0.63, 95% CI: 0.47-0.85; p=0.003) and heart attack or stroke (aOR: 0.31, 95% CI: 0.17-0.55; p<0.001) were negatively associated with undiagnosed HTN versus diagnosed HTN. Conclusion: one in four adults in Sudan had undiagnosed HTN (eight in ten of total HTN) and several associated factors that can help guide interventions were identified.