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.