Dipstick proteinuria as a surrogate marker of long-term mortality after acute myocardial infarction

Abstract

BackgroundProteinuria and reduced estimated glomerular filtration rate (eGFR) are associated with an increased risk of mortality from acute myocardial infarction (AMI). However, it is unknown whether there is a difference in prognostic value for all-cause mortality between proteinuria and eGFR during post-AMI. MethodsA consecutive series of 101 patients admitted with AMI who received angioplasty were enrolled. Dipstick proteinuria and eGFR were assessed on admission: (i) the patients were divided into 2 groups according to the presence of proteinuria (proteinuria, n=25), or not (negative, n=76), (ii) the patients were divided into 2 groups according to lower eGFR (GFR<60mL/min/1.73m2, n=31) or higher (GFR>60mL/min/1.73m2, n=70). Clinical characteristics and 3-year all-cause mortality estimated by Kaplan–Meier method were evaluated in each group. Additionally, a multivariate Cox proportional hazards model was applied to evaluate which factor was associated with all-cause mortality. ResultsMean follow-up period was 914 days. Higher brain natriuretic peptide (BNP) levels were shown in the proteinuria and lower eGFR groups, respectively (proteinuria, 301±324pg/mL; negative, 146±159pg/mL; p=0.02; lower eGFR, 294±305pg/mL; higher eGFR, 142±161pg/mL; p=0.02). Three-year all-cause mortality was higher in the proteinuria group than in the normal group (p<0.001) and in the lower eGFR group than in the higher group (p=0.006). In a Cox proportional hazards model, the presence of proteinuria [hazard ratio (95% confidence interval), 4.51 (1.07–18.96); p=0.04] was selected as one of the predictors for all-cause mortality. ConclusionsDipstick proteinuria and lower eGFR in the early phase of AMI follow-up were related to increased plasma BNP level during the sub-acute phase and long-term adverse outcome. Dipstick proteinuria may be a prognostic marker for long-term all-cause mortality.