RELATIONSHIP BETWEEN ASYMPTOMATIC HYPERURICEMIA AND RENAL FUNCTION DECLINE IN HYPERTENSIVE SUBJECTS.

Abstract

Introduction: It is well known that the deposition of uric acid crystals exert direct toxic effect on the renal parenchyma and vasculature. Both experimental and some clinical studies suggest the possibility that an increased uric acid level can lead to kidney disease even without deposition of uric acid crystals. However, other studies yielded conflicting results, especially regarding the role of uric acid in the progression of established kidney disease. Aim: To evaluate retrospectively the relationship between asymptomatic hyperuricemia and renal function decline in non-gouty hypertensive patients. Methods: We enrolled 97 hypertensive subjects, 48 with chronic kidney diseases (CKD) and 49 without CKD. Fiftyseven of them had normal (N) serum uric acid (SUA) level (SUA\7 mg/dl in men and\6 mg/dl in women) and 40 had hyperuricemia (U). Patients with hyperuricemia had higher systolic blood pressures and lower estimated glomerular filtration rate (eGFR) than N. At the end of followup period (mean: 16 months), eGFR reduction was similar in the two groups (N: -3.6 ± 12.3; U: -3 ± 13.4 ml/min/ 1.73 m2). 186 Results: Two-way ANOVA showed that this result was not influenced by renal dysfunction, diabetes, macroproteinuria, gender or smoking habit. The percentage of subjects with a value of eGFR reduction above the median was not significantly different in the two groups (N: 24.6 %; U: 27.5 %). The absence of a significant difference between the two groups, regarding the eGFR decline was confirmed by the multiple logistic regression analysis, where the variables associated with a greater eGFR reduction were only the proteinuria and the smoking habit. Conclusions: Our findings do not support the hypothesis of a significant effect of asymptomatic hyperuricemia on the renal function decline in subjects with arterial hypertension.