Comparative Effectiveness and Safety of Torsemide Versus Furosemide in Older Adults With Heart Failure

PURPOSE: Evidence on the real-world comparative effectiveness and safety of commonly used loop diuretics for heart failure is mixed, particularly among older adults who are at a higher risk of adverse outcomes. Thus, we aimed to compare the outcomes and safety profiles of torsemide and furosemide. METHODS: We conducted a new user, active comparator retrospective cohort study comparing torsemide to furosemide in Medicare fee-for-service beneficiaries with heart failure in claims data (2008-2020). Effectiveness outcomes were a composite of heart failure hospitalization or death and urgent outpatient visits requiring intravenous diuretics; safety outcomes included acute kidney injury, hypovolemia, and hypokalemia. We used 1:4 propensity score (PS) matching to adjust for confounding. We calculated PS-matched hazard ratios using Cox proportional hazard models. RESULTS: Across 328 640 matched beneficiaries, compared with furosemide, torsemide was associated with a similar, though statistically significantly lower, risk of the composite effectiveness outcome (hazard ratio [HR] = 0.97, 95% CI:0.95,0.99; incidence rate difference (IRD) = -3.79, 95% CI:-9.38,1.81 events per 1000 person-years) and lower risk for urgent visits with intravenous loop diuretics (HR = 0.88, 95% CI:0.84,0.92; IRD = -7.03, 95% CI:-9.79,-4.26 events per 1000 person-years). Torsemide was also associated with an increased risk of acute kidney injury (HR = 1.12, 95% CI:1.10,1.15; IRD = 36.89, 95% CI:31.51,42.64 events per 1000 person-years) with no observed difference in hypokalemia (HR = 1.02, 95% CI:0.91,1.14; IRD = 0.46, 95% CI:-0.51,1.42 events per 1000 person-years) and hypovolemia (HR = 1.03, 95% CI:0.98,1.09; IRD = 2.36, 95% CI:0.15,4.56 events per 1000 person-years). CONCLUSIONS: Compared with furosemide, initiation of torsemide was associated with a slightly lower risk of a composite of all-cause mortality or heart failure hospitalization and urgent visits with intravenous diuretics, but a slightly higher risk of acute kidney injury. In older adults, clinicians must balance torsemide's potential benefits with the acute kidney injury risk.