Effects of xanthine oxidase inhibitors on renal function and blood pressure in hypertensive patients with hyperuricemia

Hyperuricemia may promote the progression of hypertension and renal dysfunction. However, the effects of hyperuricemia treatment on blood pressure and renal function in adult hypertensive patients with hyperuricemia remain unclear. A total of 137 hypertensive patients with hyperuricemia (96 men and 41 women; mean age of 67 years) who recently started taking xanthine oxidase inhibitors (allopurinol or febuxostat) as outpatients were recruited. Serum uric acid level, estimated glomerular filtration rate (eGFR, ml min−1 per 1.73 m2) and blood pressure (mm Hg) were retrospectively compared immediately before and shortly after starting treatment with xanthine oxidase inhibitors. The mean blood pressure and the eGFR immediately before starting treatment were 128/71 mm Hg and 44.6 ml min−1 per 1.73 m2, respectively. Although the eGFR decreased from 46.6 to 44.6 ml min−1 per 1.73 m2 before starting treatment with xanthine oxidase inhibitors, it increased to 46.2 ml min−1 per 1.73 m2 (P=0.001, compared with immediately before treatment) without any significant changes in blood pressure after the administration of xanthine oxidase inhibitors. Multiple regression analysis revealed that the increase in eGFR after starting xanthine oxidase inhibitor treatment positively correlated with the changes in systolic blood pressure and negatively correlated with the changes in uric acid levels and the use of renin–angiotensin system inhibitors. These results suggest that xanthine oxidase inhibitors may delay the progression of renal dysfunction in adult hypertensive patients with hyperuricemia.