Prognostic significance of serum creatinine and its change patterns in patients with acute coronary syndromes.

BACKGROUND: In acute coronary syndromes (ACS), serum creatinine (sCr) levels have short- and long-term prognostic value. However, it is possible that repeated evaluations of sCr during hospitalization, rather than measuring sCr value at admission only, might improve risk assessment. We investigated the relationship between sCr baseline value, its changes, and in-hospital mortality in patients hospitalized with ACS.

METHODS: In 2,756 ACS patients, sCr was measured at hospital admission and then daily, until discharge from coronary care unit. Patients were grouped according to the maximum sCr change observed: <0.3 mg/dL change from baseline (stable renal function [SRF] group), ≥0.3 mg/dL decrease (improved renal function [IRF] group), and ≥0.3 mg/dL increase (worsening renal function [WRF] group).

RESULTS: Of the 2,756 patients, 2,163 (78%) had SRF, 292 (11%) had IRF, and 301 (11%) had WRF. In-hospital mortality in the 3 groups was 0.5%, 2%, and 14% (P < .001), respectively. Peak sCr value was a more powerful predictor of mortality (area under the curve 0.86, 95% CI 0.81-0.92) than the initial sCr value (area under the curve 0.69, 95% CI 0.63-0.77; P < .001). When sCr and its change patterns during coronary care unit stay were evaluated together, improved mortality risk stratification was found.

CONCLUSIONS: In ACS patients, daily sCr value and its change pattern are stronger predictors of in-hospital mortality than the initial sCr value only; thus, their combined evaluation provides a more accurate and dynamic stratification of patients' risk. Finally, the intermediate mortality risk of IRF patients possibly reflects acute kidney injury started before hospitalization.