C-reactive protein concentration as a predictor of intensive care unit readmission: A nested case-control study

Purpose: The purpose of this study is to assess the ability of potential clinical predictors and inflammatory markers to predict intensive care unit (ICU) readmission during the same hospitalization. Materials and Methods: A nested case-control study utilized prospectively collected de-identified data of a 22-bed multidisciplinary ICU in a university hospital. Results: There were 1405 consecutive ICU admissions in 2004, and of these, 18 were regarded as ICU readmissions (1.3%). The destination and timing of ICU discharge, the Sequential Organ Failure Assessment scores, white cell counts, and fibrinogen concentrations at discharge were not associated with ICU readmission. C-reactive protein (CRP) concentration within 24 hours before ICU discharge was associated with ICU readmission (mean CRP concentrations of cases vs controls, 177.8 vs 56.5 mg/L, respectively; P < .0001). The results remained unchanged after adjustment with the propensity scores. The area under the receiver operating characteristic curve for the CRP concentrations to predict ICU readmission was 0.884 (95% confidence interval, 0.765-0.999; P < .0001). Patients readmitted to the ICU had a higher predicted mortality in their second ICU admission (34.9% vs 26.1%; P < .01) and a longer total hospital stay (33.3 vs 20.3 days; P < .003) than patients without ICU readmission. Conclusions: A high CRP concentration within 24 hours before ICU discharge is associated with a higher risk of readmission to the ICU.