In-hospital worsening renal function is an independent predictor of one-year mortality in patients with acute myocardial infarction.

BACKGROUND: We investigated the incidence, clinical predictors and prognostic value of worsening renal function (WRF) regarding 1-year mortality in patients with acute myocardial infarction (AMI).
METHODS: We collected in-hospital data from 447 patients hospitalized for AMI in our institute within 12h of symptoms' onset. WRF was defined as a 25% or more decrease in estimated glomerural filtration rate during hospital stay. From blood samples obtained on admission and throughout hospitalization hemoglobin, white blood cell count, C-reactive protein, B-type natriuretic peptide, plasma glucose, troponin I and baseline and peak creatinine levels were measured. Ejection fraction was calculated on admission with 2D echocardiography. All patients underwent coronary arteriography and the revascularization status (complete or not) was also recorded. The end point was all-cause mortality after one-year of follow-up.
RESULTS: WRF was detected in 63 pts (16.7%) and age, ejection fraction and white blood cell count emerged as the only independent predictors. The incidence of 1-year mortality was 10.7% (48 deaths). Patients with WRF exhibited higher 1-year mortality (37.5% vs. 6.3%, log rank p<0.001) and were characterized by more severe and less completely treated coronary artery disease, greater degree of myocardial necrosis and marked neurohormonal activation. By applying multivariate Cox regression analysis WRF, B-type natriuretic peptide, ejection fraction and admission diastolic blood pressure were identified as the only independent predictors of death.
CONCLUSIONS: WRF is associated with adverse 1-year outcome in patients with AMI. Close monitoring of renal function in the acute phase of MI may substantially contribute to long-term risk stratification.