Loop diuretic down-titration in stable chronic heart failure is often achievable, especially when urinary chloride concentration is low.

BACKGROUND: This study investigates spot urinary chloride concentration in euvolemic chronic heart failure (CHF) patients.

METHODS: This prospective cohort study included 50 ambulatory CHF patients on maintenance loop diuretics without recent hospital admission, clinical signs of volume overload, or adjustment in neurohumoral blocker or diuretic therapy. Spot urinary samples were collected immediately after loop diuretic intake. Subsequently, loop diuretic dose was reduced with 50% or stopped if ≤40 mg furosemide equivalents. Successful down-titration was defined as persistent dose reduction after 7 d without body weight increase >1.5 kg.

RESULTS: Urinary chloride concentration was 3045 ± 1271 mg/L overall. Patients with higher versus lower urinary chloride concentrations took the same dose of loop diuretics [40 mg (20-40 mg) furosemide equivalents; p value = .509] and had similar plasma NT-proBNP levels [1179 ng/L (311-2195 ng/L) versus 900 ng/L (255-1622 ng/L), respectively; p value = .461]. Down-titration was successful in 72% versus 76%, respectively (p value  = 1.000). At 30 d, loop diuretic dose remained reduced in 59% versus 76% of patients, respectively (p value = .238). The proportion of patients free from diuretic therapy was 45% versus 62% in the high versus low chloride concentration group (p value = .265).

CONCLUSIONS: Loop diuretic down-titration was successful in 3 out of 4 euvolemic CHF patients, irrespectively of urinary chloride concentration on spot samples collected after diuretic intake.