LAUSR

Objectives This study aimed to identify patient characteristics associated with low urinary creatinine in morning spot urine and investigate its association with clinical outcome. Background Twenty‐four‐hour creatinine excretion is an established marker of muscle mass in heart failure and other populations. Spot urine creatinine might be an easy obtainable, cheap marker of muscle wasting and prognosis in heart failure (HF) patients. Methods Spot urine creatinine concentration was measured in 2130 patients included in the GISSI‐HF trial. We evaluated the prognostic value of urinary creatinine and its relation with clinical variables. Results Median spot urinary creatinine was 0.80 (IQR 0.50‐1.10) g/L. Lower spot urinary creatinine was associated with older age, smaller height and weight, higher NYHA class, worse renal function and more frequent spironolactone and diuretic use (all P < .02). During a median follow‐up of 2.8 years, 655 patients (31%) experienced the combined endpoint of all‐cause mortality or HF hospitalization. Lower urinary creatinine was independently associated with an increased risk of all‐cause mortality or HF hospitalization (HR, 1.59 [1.21‐2.08] per log decrease, P = .001), and all‐cause mortality (HR, 1.75 [1.25‐2.45] per log decrease, P = .001). Conclusion Lower urinary creatinine, measured in morning spot urine in patients with chronic HF, is associated with worse renal function, smaller body size, more severe HF and is independently associated with an increased risk of all‐cause death and HF hospitalization.