High furosemide dose has detrimental effects on survival of patients with stable heart failure.

INTRODUCTION

High doses of furosemide for heart failure (HF) have been correlated with an increased mortality, though whether they are a marker of disease severity or an independent predictor is unknown. We hypothesized that, in patients presenting with stable HF, the likelihood of long-term major adverse clinical events is increased by higher furosemide doses.

METHODS

We retrospectively recorded the doses of furosemide prescribed to 173 consecutive, clinically stable patients during a first ambulatory HF department visit. The low-dose group included 103 patients treated with 80 mg and the high-dose group included 70 patients treated with >80 mg of furosemide daily. Proportional hazard regression analyses were performed with single and multiple variables in search of correlates of long-term adverse clinical events. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated.

RESULTS

The baseline characteristics of the 2 groups were similar, except for estimated glomerular filtration rate, which was higher in the low- than the high-dose group (72.9 ± 19.4 vs. 60.8 ± 22.0 mL/min/ m2, p<0.001). The 3-year survival free from the composite endpoint was significantly higher in the lowdose group than in the high-dose group (93.1% vs. 60.0%, p<0.001). By multiple variable analysis, highdose furosemide was an independent predictor of an adverse outcome at 3 years (adjusted HR: 15.25; 95% CI:1.06-219.39, p=0.045). The incidence of deterioration of renal function and episodes of hypokalemia during follow up was also higher in the high furosemide dose (73.2% vs. 48.3, p=0.003, and 43.1% vs. 6.5%, p<0.001, respectively).

CONCLUSIONS

High doses of furosemide administered in order to stabilize HF patients and continued thereafter are associated with an adverse clinical outcome.