Effects of spironolactone on intradialytic hypertension: a multicentre, double-blind, randomized, crossover study

Background Intradialytic hypertension (IDH) is associated with an increase in hospitalization and mortality. Several studies have shown that spironolactone reduces pre-dialysis blood pressure. However, none evaluated its effect on IDH. This study aims to evaluate the effects of spironolactone on IDH. Methods A 24-week, two-treatment, four-period, multicentre, double-blind, randomized, crossover study was conducted in stable maintenance haemodialysis (HD) patients who experienced IDH in >30% of their sessions during the past 3 months. Each participant was randomly assigned to one of four treatment sequences. In each intervention period, patients received a single dose of 50 mg spironolactone or a placebo 30 minutes before undergoing HD for 4 weeks according to their preassigned sequence, separated by a 2-week washout period. The primary outcome was an incidence of IDH. Results A total of 49 eligible patients were recruited with a total of 1211 dialysis sessions. The mean age was 54 ± 14 years and the mean systolic and diastolic blood pressures (SBP and DBP) were 145 ± 15 and 75 ± 10 mmHg, respectively. All patients had hypertension. The average number of antihypertensive drugs was 3.5 ± 1.4. Spironolactone reduced the incidence of IDH compared with placebo (57% versus 69%, P for treatment effect < .001). Patients receiving spironolactone had lower peak intradialytic SBP (161 ± 14 versus 165 ± 13 mmHg, P = .003), mean intradialytic SBP (149 ± 13 versus 152 ± 12 mmHg, P = .01) and post-dialysis SBP (152 ± 15 versus 157 ± 14 mmHg, P < .001) than placebo. Conclusion In maintenance HD patients who had frequent IDH, a pre-dialysis 50-mg spironolactone administration significantly decreased the incidence of IDH. Trial registration Thai Clinical Trial Registry, reference number TCTR20200604013.