Abstract
Classification of hyperuricemia is useful for the choice of uric acid (UA)-lowering drugs, however, the classification by using 24-h or 60-min urine collection is not conventional. The aim of the present study was to investigate the usefulness of urinary UA/urinary creatinine (UUA/UCr) determined by spot urine. Subjects were 1067 hypertensive outpatients without taking diuretics or UA-lowering drugs (606 females and 461 males, mean age 60±13 (SD) years), who had been followed at National Kyushu Medical Center, Fukuoka, Japan. Patients underwent 24-h home urine collection to determine UA metabolism. In addition, we compared the classification of hyperuricemia by 24-h urine collection to that by UUA/UCr in spot urine in 177 subjects. Based on 24-h urine collection, decreased UA excretion was found in 89% of the hypertensive patients and 92% of the hypertensive patients with hyperuricemia. None of the patients who showed UUA/UCr in 24-h urine less than 0.5 turned to be overproduction type of hyperuricemia. On the other hand, 99% of the patients whose UUA/UCr in spot urine was less than 0.5 showed decreased UA excretion by 24-h urine collection. UUA/UCr determined by 24-h urine was positively correlated with that determined by spot urine (r= 0.42, p<0.01). When a cutoff value of 0.5 was adopted, consistent classification by both 24-h and spot urine UUA/UCr was obtained in 69.5% of the patients.
