Correlates of serum lipids and lipoproteins in Congolese patients with arterial hypertension.

OBJECTIVE: The purpose of this study was to assess the prevalence of dyslipidaemia and the correlates of serum lipids and lipoproteins among Congolese subjects with and without arterial hypertension.
METHODS: One hundred hypertensive patients attending the outpatient clinics at the University of Kinshasa Hospital, and 100 age- and sex-matched controls recruited among hospital personnel or blood donors entered the case-control study. Their blood pressure (BP), heart rate (HR), body mass index (BMI), waist-to-hip ratio (WHR), serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), plasma fibrinogen (only in patients) and fasting glucose, serum uric acid, creatinine and creatinine clearance (CrCl) were compared using the Student's t-test or Chi-square test as appropriate. Associations between continuous variables were assessed with Pearson correlation coefficients, and correlates of lipids and lipoproteins were determined using multiple linear-regression analysis.
RESULTS: Compared to healthy controls, hypertensive patients had greater BMI (p <or= 0.05) and WHR (p <or= 0.01), and higher levels of fasting plasma glucose (p <or= 0.05), serum uric acid (p <or= 0.05) and creatinine (p <or= 0.001). The average TC (4.96 +/- 1.18 mmol/l for controls vs 5.01 +/- 1.49 mmol/l for hypertensives), LDL-C (3.46 +/- 1.16 mmol/l vs 3.36 +/- 1.32 mmol/l) and HDL-C (1.19 +/- 0.39 mmol/l vs 1.27 +/- 0.39 mmol/l) were similar and within the normal ranges, whereas TG in hypertensives (1.03 +/- 0.66 mmol/l) were significantly higher (p <or= 0.05) than in controls (0.85 +/- 0.48 mmol/l). Dyslipidaemia was observed in 33 controls (33%) and 40 hypertensive patients (40%). Sixteen controls (16%) and 23 hypertensive patients (23%) had TC >or= 6.20 mmol/l. In hypertensive patients, TC (r = 0.24; p < 0.01) and LDL-C (r = 0.20; p < 0.05) were positively correlated to plasma fibrinogen. A positive correlation was also observed between TC and LDL-C (r = 0.91; p < 0.001), HDL-C and CrCl (r = 0.28; p < 0.001), and TG and glucose (r = 0.24; p < 0.01), whereas TG were negatively correlated to HDL-C (r = -0.38; p < 0.001). In multiple linear-regression analysis, LDL-C, HDL-C, TG and age accounted for 87% (R2) of variation in TC levels; plasma glucose and HDL-C for 19% (R2) of variation in TG levels; and TG and CrCl for only 17% (R2) of variation in HDL-C levels.
CONCLUSIONS: The present data indicate that dyslipidaemia affects a substantial proportion of healthy and hypertensive Congolese subjects. Furthermore, hypertension is associated with a cluster of risk factors characteristic of the metabolic syndrome, of which overweight/central obesity could be the cornerstone. Management of arterial hypertension should therefore focus both on lowering high blood pressure and correcting associated lipid disorders.