Inhospital and 1-year Mortality of Patients Who Develop Worsening Renal Function Following Acute ST-elevation Myocardial Infarction

Background: Recent studies have emphasized the prognostic value of baseline creatinine or estimated creatinine clearance in the setting of acute coronary syndromes. However, the prevalence and prognostic significance of worsening renal function (WRF) in patients with acute ST-elevation myocardial infarction are unknown.

Methods: We studied 1038 patients presenting with acute ST-elevation infarction. WRF was defined as an increase of > or =0.5 mg/dL in creatinine level at any point during hospital stay. The relation between WRF and subsequent inhospital and 1-year mortality was analyzed by use of multivariate logistic regression and Cox proportional hazards models, respectively, controlling for covariates.

Results: WRF occurred in 98 (9.6%) patients during hospital stay. Baseline renal dysfunction (calculated glomerular filtration rate <60 mL/min) and WRF were strong independent predictors of inhospital mortality (adjusted odds ratios 2.8, 95% CI 1.3-5.9; and 11.4, 95% CI 6.6-19.5, respectively). In a Cox multivariate analysis, both baseline renal dysfunction (adjusted hazard ratio 2.8, 95% CI 1.6-4.9) and WRF (adjusted hazard ratio 7.2, 95% CI 4.9-10.4) remained independent predictors of 1-year mortality. WRF provided incremental prognostic value toward the prediction of 1-year mortality when added to clinical risk predictors and baseline renal function. The increased mortality associated with impaired baseline renal function was largely caused by events occurring in patients with WRF.

Conclusion: WRF occurring during admission for ST-elevation myocardial infarction is a powerful and independent predictor of inhospital and 1-year mortality. Small elevations of serum creatinine may serve as a simple marker to identify patients at a very high risk.