early acute kidney injury based on serum creatinine or cystatin c in intensive care unit after major trauma

background: acute kidney injury (aki) is a common problem in critically ill patients and is independently associated with increased morbidity and mortality. recently, serum cystatin c has been shown to be superior to creatinine in early detection of renal function impairment. we compared estimated gfr based on serum cystatin c with estimated gfr based on serum creatinine for early detection of renal dysfunction according to the rifle criteria. methods: during 9 months, three hundred post trauma patients that were referred to the intensive care unit of a referral trauma hospital were recruited. serum creatinine and serum cystatin c were measured and the estimated gfr within 24 hours of icu admission was calculated. the primary outcome was the incidence of aki according to the rifle criteria within 2 nd to 7 th day of admission. results: during the first week of icu admission,21% of patients experienced aki. after adjusting for major confounders, only the patients with first day's serum cystatin level higher than 0.78 mg/l were at higher risk of first week aki (or=6.14, 95% ci: 2.5-14.7, p<0.001). first day’s serum cystatin c and injury severity score were the major risk factors for icu mortality (or=3.54, 95% ci: 1.7-7.4, p=0.001) and (or=4.6, 95% ci: 1.5-14, p=0.007), respectively. conclusion: within 24 hours after admission in icu due to multiple trauma, high serum cystatin c level may have prognostic value in predicting early aki and mortality during icu admission. however, such correlation was not seen neither with creatinine nor cystatin c based gfr.