Serum uric acid change in relation to antihypertensive therapy with the dihydropyridine calcium channel blockers.

PURPOSE: We investigated serum uric acid changes in relation to the achieved clinic and ambulatory blood pressure after 8 weeks of antihypertensive therapy with two dihydropyridine calcium channel blockers. MATERIALS AND METHODS: The study participants were patients with clinic and ambulatory hypertension, enrolled in a randomised controlled trial that compared amlodipine (5-10 mg, n = 215) and nifedipine gastrointestinal therapeutic system (GITS, 30-60 mg, n = 203). Hyperuricaemia was defined as a serum uric acid concentration of ≥420 µmol/L in men and ≥360 µmol/L in women. Analysis of covariance and multiple regression analyses were performed to study the associations between serum uric acid changes and the achieved clinic and ambulatory blood pressure during follow-up. RESULTS: At baseline, 67 (16.0%) of the 418 patients had hyperuricaemia. Antihypertensive treatment reduced clinic and 24-h daytime and night-time systolic/diastolic blood pressure by a mean (±standard error [SE]) change of -17.4 ± 0.6/-8.6 ± 0.4 mm Hg and -13.7 ± 0.5/-8.3 ± 0.3 mm Hg, -13.8 ± 0.6/-8.4 ± 0.4 mm Hg, and -12.7 ± 0.7/-8.0 ± 0.4 mm Hg, respectively. Antihypertensive treatment reduced serum uric acid by a mean (±SE) change of -9.3 ± 2.8 µmol/L. The serum uric acid changes differed according to the achieved clinic and ambulatory blood pressure, and were statistically significant (mean ± SE -20.6 ± 6.6 to -10.7 ± 2.9 µmol/L, p ≤ 0.04) at the systolic/diastolic ranges of 130-139/≥90 mm Hg in clinic pressure, and <130/75-84 mm Hg, <145/80-84 mm Hg and <120/65-69 mm Hg in 24-h, daytime and night-time ambulatory pressure. CONCLUSION: Our study showed that antihypertensive therapy with a dihydropyridine calcium channel blocker was associated with reduced serum uric acid, especially when 24-h ambulatory systolic blood pressure was controlled.