The Association Between High-Dose Diuretics and Clinical Stability in Ambulatory Chronic Heart Failure Patients

ObjectiveIn chronic heart failure (HF), diuretic doses increase as the disease progresses, often after hospitalization for instability, and have been associated with worsening renal function and increased mortality.Methods and ResultsA prospective observational analysis of 183 patients in an advanced HF clinic stratified at baseline by diuretic dose (low dose ≤ 80 mg, high dose > 80 mg furosemide equivalent) was performed. All patients were followed for 1 year, and the primary outcome was a combined HF event of admission for HF, cardiac transplant, mechanical cardiac support, or death. Compared with patients taking low-dose diuretics (n = 113), patients taking high-dose diuretics (n = 70) had more markers of increased cardiovascular risk and were more likely to have a history of recent instability (33% vs 4.4% in low dose, P < .001). High doses of diuretics were a strong univariate predictor of subsequent HF events (hazard ratio 3.83, 95% confidence interval 1.82–8.54); however, after adjustment for clinical stability, diuretic dose no longer remained significant (hazard ratio 1.53, 95% confidence interval 0.58–4.03).ConclusionHigh-dose diuretics may be more of a marker than a cause of instability. A history of HF stability during the past 6 months is associated with an 80% lower risk of an HF event during the next year, independently of baseline diuretic dose.