Cardiovascular risk factor profile of Black Africans undergoing coronary angiography

Abstract

Background: Coronary artery disease (CAD) is a growing epidemic on the African continent It remains uncertain whether the risk factors identified as contributing to CAD in white populations contribute to a similar extent to CAD incidence in black populations. No data of the local population exists that is based on the coronary angiogram (CA). Objectives: To analyse the relationship of conventional cardiovascular risk factors with presence of CAD in black Africans. Design: This was a dual-armed study, consisting of retrospective and prospective comparative arms. Subjects: Black Africans who underwent coronary angiography. Setting: Nairobi Hospital, Cathereterization laboratory. Main outcome measures: The conventional risk factors: age, male gender, hypertension, obesity, smoking, diabetes mellitus, dyslipidaemia, alcohol use and interventricular septum (IVS) hypertrophy, as a marker of LVH. Results: One hundred and sixty nine patients fulfilled the inclusion criteria; 144 in the retrospective arm and 25 in the prospective. The larger retrospective arm showed that the group with CAD, compared to the normal group, was significantly older, with a higher mean age of 54.4 years compared to 49.8 years (P=0.005); had significantly more males, with a male to female ratio of 5.5:1 compared to 2.3:1 (P=0.045); had a very significantly larger proportion of diabetics (38.5% compared to 12%, P=0.0002), and also had a significantly larger proportion of patients with dyslipidaemia (67.3% compared to 35.9%, P=0.0003). The percentage of hypertensives was high in both groups, with (65.4%) in the CAD group and 62% in the Normal group being hypertensive (P=0.68). The percentage of smokers was small in both groups, being 15.4% and 13% respectively. Smoking, increased BMI, alcohol use, and increased IVS were each found to be distributed equally in both groups. In addition, the Waist hip ratio (WHR) and waist circumference (WC) did not differ significantly between the two groups studied. Conclusions: The risk factors found to be most strongly associated with presence of angiographically-detected CAD in the population studied were diabetes mellitus, dyslipidaemia, age and male gender. There was a high prevalence of hypertension, with equal distribution in both groups under study; hence this risk factor was not discriminatory for CAD. There was a low prevalence of cigarette smoking in this particular study; it was not predictive of presence of CAD.