The comparative antihypertensive efficacy of torasemide and mineralocorticoid receptor antagonists in patients with resistant hypertension

Abstract Objective To compare the antihypertensive efficacy of antagonists of mineralocorticoid receptor (AMR) (spironolactone (SPR) or eplerenone (EPL)) and torasemide (TOR) as an add-on therapy in true resistant hypertensive (RH) patients. Design and methods: We studied 208 true RH patients treated with fixed-dose triple-combination in maximum tolerated doses and divided them into two groups (gr). The 1st gr. received AMR (SPR 25–50 mg or EPL 25-50 mg), the 2nd gr. TOR (5-10 mg) once daily for 12 weeks of each medication. Average doses of SPR (34.5±8.4 mg) and EPL (36.3±9.7 mg) were comparable (P 0.05), average dose of TOR was (7.5±0.9 mg). Patients took the drugs consequently; office and 24-hour ambulatory BP were measured before and after each rotation of the drug. Serum potassium, eGFR, and potential side effects were monitored. Initial plasma aldosterone (PA) level, active renin concentration (ARC), and urinary sodium excretion (USE) were tested as predictors of BP response in multivariable analysis. Results The AMRs and TOR equally declined diastolic BP (office, average 24-h, day- and night-time DBP). AMRs were more effective than TOR in systolic BP (SBP) lowering: office SBP declined by 18.5 mm Hg vs 16.5 mm Hg (P = 0.02), average 24-h SBP by 11.9 mm Hg vs 8.8 mm Hg (P = 0.001), daytime SBP by 11.2 mm Hg vs 7.8 mm Hg (P = 0.001) on AMRs and TOR respectively. 36.7 % of RH patients achieved office and 24-hour ambulatory BP targets with AMRs and 29.6% with TOR (P = 0.001). After 12 weeks of treatment, plasma potassium level increased by 6.8 % (P = 0.001) on AMRs and did not change on TOR, although eGFR decreased on TOR by 6.8 % (P = 0.03). PA level (β = 0.433, P = 0.03), ARC (β= -0.296, P = 0.02), and 24-h USE (β= 0.421, P = 0.01) were the predictors of the BP-lowering effect of AMRs. Only PA level (β = 0.359, P = 0.03) predicted BP reduction under TOR treatment. Conclusions AMRs were more effective than TOR in lowering SBP and achieving target BP. The efficacy of AMRs was directly related to PA and USE levels and inversely related to ARC, while only PA level was a predictor of TOR's BP reduction. TOR can be recommended for RH patients with AMR intolerance, including high serum potassium levels, with monitoring of eGFR.