Combination of SGLT2 Inhibitors and Loop Diuretics in the Treatment of Heart Failure

Background: Administration of SGLT2 inhibitors leads to a reduction in the dosage of loop diuretics in heart failure (HF) patients; however, it is unclear in what patients the dosage can be reduced. We investigated the factors related to the reduction in loop diuretics in patients who have started receiving dapagliflozin, an SGLT2 inhibitor. Methods: In total, 126 consecutive patients with HF who received dapagliflozin for HF at our institution between December 2020 and March 2022 were enrolled. We investigated the change in the dosage of diuretics at the time of dapagliflozin administration and after 6 months and evaluated factors at the time of dapagliflozin initiation that were associated with the dosage of loop diuretic reduction. Results: The median of loop diuretics dosage (oral furosemide equivalent) at the time of dapagliflozin administration was 20 mg/day (the mean dosage; 29.5 ± 26.5 mg/day), and after 6 months it decreased to 10 mg/day (the mean dosage; 14.5 ± 15.9 mg/day) (p < 0.001). Multivariate analysis showed that the three factors of in-hospital start of dapagliflozin, % patients on β-blockers, and the dosage of loop diuretics independently predicted the reduction in loop diuretic dosage. Even in analyses excluding patients who initiated dapagliflozin during hospitalization, loop diuretic dosage independently predicted loop diuretic reduction in multivariate analysis. The receiver operating characteristic curve for predicting reduced loop diuretic showed that the cut-off value for loop diuretic at the time of administration of dapagliflozin was 20 mg/day of oral furosemide equivalent. Conclusions: The dosage of loop diuretic used when dapagliflozin was started is a factor that predicts a subsequent reduction in the dose of loop diuretics.