2022 Volume 46 Issue 2 Pages 131-140
Background: Nocturnal hypertension is chiefly based on an excessive salt-intake, and diuretics which promote urinary excretion of sodium are known to decrease blood pressure (BP) at night. It was reported that diuretics tended to cause hyperuricemia, and correcting the uric acid (UA) level led to hypotension. The incidence of hyperuricemia, changes in BP and BP variability due to UA-lowering therapy, and differences depending on the type of drugs were examined in hypertensive patients receiving diuretics.
Methods: The frequency of hyperuricemia in hypertensive patients was studied with or without diuretics. For 78 patients taking diuretics among hyperuricemia-combined hypertensive subjects, serum UA (SUA), home morning BP (HMBP), and 24-hour ambulatory BP monitoring (ABPM) were measured before and 24 weeks after the administration of benzbromarone or febuxostat and assessed retrospectively. Coefficient of variation (CV) calculated from HMBP was employed as an indicator of the daily fluctuation in BP. Analyzing circadian rhythms via ABPM data, dippers and non-dippers regarding night-time BP were defined as 10-20% and below 10% decline from daytime BP, respectively.
Results: For refractory hypertension, the complication rate of hyperuricemia was 87.2% in recipients of diuretics, being clearly higher than 43.3% in non-diuretic users. When SUA ≦ 6.0 mg/dL was achieved by UA-decreasing treatment, average HMBP and 24-hour BP were both reduced and CV was decreased significantly. After achievement of the target SUA, the average BPs for day and night were lower as compared with pre-treatment values in either case, while the step-down degree at night was smaller. In terms of drug-specific effects, benzbromarone and febuxostat given to the subjects elicited equivalent decreases in diurnal BP, whereas only the latter reduced night-time BP significantly. Moreover, the degree of decrease in the non-dipper/dipper ratio in the febuxostat group was greater even without achieving the desired SUA.
Conclusion: In patients with diuretic-resistant hypertension, improved BP control and a reduction in daily BP variation can be expected with UA-reducing medication. Additionally, diurnal hypertension could arise from hyperuricemia, whereas it was suggested that nocturnal hypertension could be evoked by XO activation rather than an increase in SUA.
