Serum uric acid in hypertensive patients.

Both the average serum uric acid and annual increment were determined in 250 treated patients attending a hypertension clinic. The average serum uric acid was greater in men compared with women, in patients receiving a thiazide diuretic and in patients with a high average plasma urea. The mean annual increment in uric acid was close to zero (0.0017 mmol/litre per year) and was not related to sex, age, blood pressure control, diuretic therapy, or plasma urea. There was an unexplained positive association between annual increment and methyldopa therapy though this drug was not associated with a significantly high average serum uric acid. A table is presented giving the theoretical upper limits for average serum uric acid according to sex, plasma urea concentration, and whether or not a thiazide diuretic has been prescribed. It is hoped that this table will be of assistance in assessing the normality or otherwise of a high serum uric acid found in a hypertensive patient.