Serum Uric Acid Levels among Nigerians with Essential Hypertension

There is an ongoing debate on the role of serum uric acid as an independent risk factor for hypertension and renal disease. This study determined the serum uric acid levels of Nigerians with essential hypertension and also evaluated the association between serum uric acid levels and blood pressure of these patients. A retrospective case-control study of three hundred and fifty one patients with essential hypertension seen at the hypertension clinic of Aminu Kano Teaching Hospital, Kano between January 2004 and December 2008. The control group comprised of one hundred apparently healthy non hypertensive subjects. The clinical characteristics including blood pressure measurement, serum uric acid, urea, creatinine, lipid profile and glucose were evaluated.The mean systolic and diastolic blood pressures of the male patients were 156mmHg and 101mmHg respectively, while those of the male controls were 120 ± 6.0 and 80 ± 5 respectively. The mean serum uric acid, fasting blood glucose, urea and creatinine were 483umol/L, 5.7mmol/L,6.61mmol/L, 93umol/l respectively compared to those of the male controls which were 326 ±10μmol/l, 5.0± 0.5mmol/l, 4.2± 0.12mmol/l, 5.16mmol/l ± 0.12 and 69±2.71μmol/l respectively. The mean systolic and diastolic blood pressures of the female patients were 158mmHg and 101mmHg, while those of the female controls were 101±2 and 62±9 respectively. The mean serum uric acid, fasting blood glucose, urea and creatinine of the female patients were 434umol/L, 5.3mmol/L 6.20mmol/L, and 88umol/L respectively while those for the female controls were 290±9μmol/l, 4.8±0.5mmol/l, 5.02±0.28 mmol/l, 62±0.36μmol/l respectively. Hyperuricaemia was observed in 59.3% of the male study patients and 62% of the female study patients. Serum uric acid correlated positively with both systolic blood pressure (r=0.192, p<0.001) and diastolic blood pressure (r=0.216; p<0.001). Hyperuricaemia is common among Nigerian patients with essential hypertension and there is an association between serum uric acid level and blood pressure. Further studies on the pathophysiologic significance of hyperuricaemia in these patients are recommended.