Predictive values of urinary albumin for worsening renal function during hospitalization and after discharge in patients hospitalized in cardiac intensive care units

We sought to assess the predictive value of the urinary albumin-creatinine ratio (UACR) for worsening renal function (WRF) during hospitalization and after discharge in heterogeneous cohort of 920 patients (597 men; mean age, 71 years) treated in cardiac intensive care units (CICUs). Urinary albumin and serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) were measured on admission. Microalbuminuria was defined as a UACR > 30 mg/g creatinine, whereas macroalbuminuria was defined as a UACR > 300 mg/g creatinine. WRF after discharge was defined as a ≥ 30% decline in the creatinine-based estimated glomerular filtration rate (eGFR) or incident end-stage kidney disease (ESKD). WRF during hospitalization was diagnosed by the Kidney Disease: Improving Global Outcome criteria. WRF after discharge occurred in 187 patients (20%), including one with ESKD. In multivariable Cox analysis, UACR was independent predictors of WRF in the overall cohort and in a subcohort without diabetes. Kaplan–Meier curves showed a graded increase in WRF risk, accompanied by higher UACR and NT-proBNP values, in both groups ( P < 0.001). Adding UACR and NT-proBNP to eGFR improved discrimination beyond eGFR alone and beyond any single biomarker. Albuminuria was a significant independent predictor of WRF during hospitalization and adding it to eGFR improved the predictive value for WRF. Patients who developed WRF after discharge had a higher risk of 12-month mortality and major adverse cardiovascular events compared with those who did not. Urinary albumin levels appear to be a promising approach for predicting renal impairment, both during hospitalization and after discharge in patients hospitalized in CICUs.