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

BACKGROUND: Proteinuria 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.

METHODS: A 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/1.73m(2), n=31) or higher (GFR>60mL/min/1.73m(2), 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.

RESULTS: Mean 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.

CONCLUSIONS: Dipstick 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.