Uric Acid Metabolism in a Sample of Egyptian Hypertensive Patients with Normal Kidney Function

Abstract

Background: Hyperuricemia is commonly associated with hypertension. Also, it is well known to coincide with the metabolic syndrome but is still not recognized as a risk factor. So, we aimed to evaluate hyperuricemia among a sample of hypertensive Egyptians with normal renal function. Methods: this study was performed on 303 hypertensive patients aged 30-69 years. Patients were divided into 2 groups according to the level of uric acid: group 1 composed of 168 hypertensive hyperuricemic patient sand group2 composed of 135 hypertensive normouricemic patients. All patients were subjected to complete medical history and detailed clinical examination including body mass index (BMI), complete blood count (CBC), serum creatinine, BUN, FBS, cholesterol, triglycerides, uric acid, sodium, potassium, urinary uric acid, urinary creatinine, urinary uric acid to creatinine ratio and fractional excretion of uric acid(FEUA). Results: The overall prevalence of hyperuricemia was 55.4%. Uric acid correlated significantly with age (p 0.05). Serum uric acid found to correlate significantly (p<0.001) with urinary uric acid, urinary creatinine and negatively with FEUA denoting early tubular defect of the kidney. Also, Urinary uric acid, urinary creatinine and urinary uric acid/creatinine ratio were higher in group 1than in group 2 (p values were<0.001, <0.001 and <0.05 respectively). FEUA was found to be significantly lower in group 1 than in group 2 (p<0.01). We found, also, that serum sodium level was significantly higher in the hyperuricemic group than in the normouricemic group (p<0.001) denoting the role of Na+ in the development of hypertension and defective renal excretion of uric acid. Conclusion: We conclude that the incidence hyperuricemia in our sample of Egyptian hypertensive patients was (55.4%). Impaired renal clearance of uric acid occurs before deterioration of GFR. Serum uric acid should be measured in all cases of hypertension together with BMI, total cholesterol, triglycerides and should be treated to avoid consequent metabolic complications. Hypertensive patients with hyperuricemia should be warned strictly of high sodium diet.