Impact of prealbumin levels on mortality in patients with acute kidney injury: An observational cohort study

Objective: We evaluated the prognostic value of prealbumin (transthyretin) levels in patients with acute kidney injury (AKI). Study Design: This was a longitudinal, single-center, observational cohort study. Setting: The setting was a university-affiliated hospital. Participants: One hundred and sixty-one consecutive patients with AKI matched at least one of the Risk, Injury, Failure, Loss, End Stage (RIFLE) criteria for increased serum creatinine, and had requested a nephrology consultation between April 2000 and March 2006. Methods: We conducted a computer-assisted review of all cases of AKI seen by a nephrologist between April 2000 and March 2006. We used Cox proportional hazards models to estimate the risk of in-hospital mortality associated with serum prealbumin level at the beginning of the nephrology consultation. Results: Clinicopathologic variables were compared between patients with a serum prealbumin level <11 mg/dL (the exposed group; cutoff point, median) and patients with a serum prealbumin level >= 11 mg/dL (the control group). In-hospital mortality rates associated with prealbumin levels were 45.0% for <11 mg/dL, and 19.8% for >= 11 mg/dL (P =.001). After adjusted analysis, the presence of a serum prealbumin level <11 mg/dL was significantly associated with increased in-hospital mortality (hazard ratio, 2.10; 95% confidence interval, 1.08 to 4.08), compared with patients with the same Liano scoring, the same RIFLE classes, and the same treatment for AKI, but with a serum prealbumin level >= 11 mg/dL. In addition, each increment of 5 mg/dL of serum prealbumin was associated with an adjusted 29% decrease of in-hospital mortality (hazard ratio, 0.71; 95% confidence interval, 0.52 to 0.96). Conclusions: Serum prealbumin levels <11 mg/dL were strongly associated with a higher risk of death, independent of AKI severity, comorbid illnesses, serum C-reactive protein levels, and other possible confounders. The measurement of serum prealbumin levels may be an inexpensive and useful tool in the evaluation of the risk profiles of AKI patients. (C) 2008 by the National Kidney Foundation, Inc.