THE EFFECT OF ALLOPURINOL AND FEBUXOSTAT ON BLOOD PRESSURE IN ADULTS WITH CHRONIC HYPERURICEMIA

Abstract

Objective: To observe the effect of the xanthine oxidase inhibitors Allopurinol and Febuxostat on blood pressure in adults with chronic hyperuricemia. Design and method: This was a sub-study of the Febuxostat versus Allopurinol Streamlined Trial (FAST). FAST was a randomised controlled trial comparing the cardiovascular safety of febuxostat and allopurinol in individuals with symptomatic hyperuricemia previously receiving allopurinol. At the screening visit, patients were invited to participate in the Blood Pressure (BP) sub-study. A validated BP monitor and an instruction booklet were provided. Each set of home BP measurements was taken over four consecutive days, three times each in the morning and evening. BP was recorded at baseline (on allopurinol therapy), after 7-days allopurinol washout, and 8 weeks after randomisation to febuxostat or allopurinol. Differences in BP in the allopurinol and febuxostat group were evaluated. The relationship between serum uric acid level reductions and BP changes was also assessed. Results: Between December 2012 and January 2014, 298 FAST participants consented to the BP sub-study. 223 participants who submitted a complete set of BP data were included in the analysis; 104 were randomised to Allopurinol and 119 to Febuxostat. Baseline characteristics were balanced between groups. Overall mean change in BP from washout to 8 weeks of randomised treatment was not significant in either group [Mean BP change in Allopurinol arm: SBP -0.10 mmHg (95% CI -1.76,1.56), p = 0.9; DBP 0.50 mmHg (95% CI -1.82,2.81), p = 0.6. Mean BP change in Febuxostat arm: SBP -0.77 mmHg (95% CI -4.20,2.67), p = 0.7; DBP -0.41 mmHg (95% CI -2.56,1.73), p = 0.7]. No significant BP differences were observed between groups at each time point. Reduction in serum uric acid by > 60 μmol/L at 8 weeks on either therapy was not associated with statistically significant changes in BP. Conclusions: There was no significant difference in the effect of allopurinol or febuxostat on blood pressure after 8 weeks of randomised therapy in the FAST study. Larger reductions in serum uric acid at 8 weeks had no effect on BP change.