Target-organ damage and cardiovascular complications in hypertensive Nigerian Yoruba adults: a cross-sectional study

BACKGROUND: Hypertension is a major challenge to public health as it is frequently associated with sudden death due to the silent nature of the condition. By the time of diagnosis, some patients would have developed target-organ damage (TOD) and associated clinical conditions (ACC) due to low levels of detection, treatment and control. TOD and ACC are easy to evaluate in a primary healthcare (PHC) setting and offer valuable information for stratifying cardiovascular risks in the patient. The aim of this study was to evaluate the prevalence and correlates of TOD and established cardiovascular disease (CVD) in hypertensive Nigerian adults. METHODS: A cross-sectional study was conducted on 2 000 healthy Yoruba adults between 18 and 64 years who lived in a rural community in south-western Nigeria. Participants diagnosed to have hypertension were examined for TOD and ACC by the presence of electrocardiographically determined left ventricular hypertrophy (LVH), microalbuminuria or proteinuria, retinopathy, or history of myocardial infarction and stroke. RESULTS: A total of 415 hypertensive participants were examined and of these, 179 (43.1%) had evidence of TOD and 45 (10.8%) had established CVD. TOD was associated with significantly higher systolic (SBP) and diastolic blood pressure (DBP). The prevalence of LVH was 27.9%, atrial fibrillation 16.4%, microalbuminuria 12.3%, proteinuria 15.2%, hypertensive retinopathy 2.2%, stroke 6.3%, congestive heart failure (CHF) 4.6%, ischaemic heart disease 1.7%, and peripheral vascular disease 3.6%. Compared with those with normal blood pressure (BP), the multivariate adjusted odds ratios (95% confidence interval) of developing TOD was 3.61 (0.59–8.73) for those with newly diagnosed hypertension; 4.76 (1.30–13.06) for those with BP ≥ 180/110 mmHg; and 1.85 (0.74–8.59) for those with diabetes mellitus. CONCLUSIONS: This study provides new data on TOD and its correlates in a nationally representative sample of hypertensive adults in Nigeria. In this low-resource setting, attempts should be made to detect hypertensive patients early within the community and manage them appropriately before irreversible organ damage and complications set in. The methods used in this study are simple and adaptable at the primary healthcare level for planning prevention and intervention programmes.