Metabolic Syndrome in Hypertensive Nigerians: Risk Factor Analysis

Abstract

Objectives: To determine the prevalence of metabolic syndrome (MS) and adequacy of the National Cholesterol Education Programme/ Adult Treatment Panel III (ATP III) criteria for the diagnosis of the MS in hypertensive Nigerians. Materials and Methods: Four hundred and thirty six hypertensive patients, (men 49 %), aged ≥ 35 years who were randomly recruited from Medical Outpatient clinics of the University of Nigeria Teaching Hospital, Enugu, Nigeria were studied. Waist circumference (WC) and blood pressure (BP) were measured in addition to fasting plasma glucose (FPG), Triglyceride (TG) and high density lipoprotein-cholesterol (HDL-C) using standard laboratory techniques. Results: MS prevalence of 45.6% was recorded with more women (54%) than men (36.4%) having the syndrome. Sex-specific and significant differences were recorded only in waist circumference (WC) (<0.05) of the subjects with the female subjects recording higher mean value (98.9 ±13.3 cm) than the male patients (93.2±12.9 cm). The ATP III criterion for WC (>102cm) gave sensitivity of 69.4%, specificity (71.6%), positive predictive value (PPV) of 67.2% and odd ratio (OR) of 5.7 among the males-plus-females patients. There were improvement in these indices when a WC ≥ 93cm was used with values of 79.9%, 62.9%, 72% and 6.7 for sensitivity, specificity, PPV and OR respectively and MS prevalence of 54.4% with improvement most significant among the male subjects. The ATP III criterion for female WC (>88cm) gave a low specificity (41.7%), which improved (46.1%) when WC ≥ 93cm was used. While the ATP III criterion for HDL-C gave low predictive indices for male, but improved when 1.3mmol/l was used, it was adequate for the female subjects. However, while the ATP III criterion for TG was adequate in all the groups, it gave low predictive values for FPG, with better results among the males than in the females Conclusions: The ATP III criteria were not wholly suitable for the diagnosis of the MS in the hypertensive Nigerians. The criteria exhibited sex-specific variations in their predictive potentials. WC (≥93cm) for men and women, raised fasting TG (≥ 1.70mmol/l0, raised BP (≥130/85mmHg), low HDL-C (≤ 1.3mmol/l) for men and women, FPG (>5.6mmol/l) were suggested as more appropriate for the diagnosis of MS in the study population.