C-reactive protein/albumin ratio at ICU discharge as a predictor of post-ICU death: a new useful tool

Introduction

There are classical predictors of death after ICU discharge, such as age, severity of disease and level of nursing care. CRP concentrations at discharge have also been reported as a predictor of in-hospital outcome, but with controversial results. Considering that albumin is a negative acute-phase protein and its decrease may be an indicator of disease severity, we hypothesized that the CRP/albumin ratio could be a marker of unfavorable outcomes in the post-ICU period.

Objective

This study aimed to investigate whether the CRP/albumin ratio at ICU discharge may be a predictor of post-ICU death. We also evaluated which is the best cut-off value of the CRP/albumin ratio to predict mortality.

Methods

Patients discharged from the ICU after at least 72 hours of stay were retrieved from our prospective collected database. A multivariate analysis was performed using a backward-LR binary logistic model taking in-hospital death as a dependent variable and age, APACHE II at admission, comorbidities, ICU length of stay (LOS), support during ICU, SOFA at ICU discharge, admission characteristics and CRP/albumin ratio as independent variables. ROC curves and the Youden index were used to calculate the best cut-off value of the CRP/albumin ratio.

Results

We retrieved 548 patients. Mean age was 49 ± 19 years, median APACHE II score at admission was 16 (10 to 21) and median SOFA score at discharge was 2 (1 to 3). The main causes of admission were septic syndromes and respiratory failure. The in-hospital mortality after ICU discharge was 18.6%. The ICU length of stay was 7 (4 to 11) days. At the moment of ICU discharge the median CRP was 47 (22 to 109) mg/l, albumin 27 (23 to 31) g/l and the mean of CRP/albumin ratio was 3. The multivariate analysis resulted in the following independent in-hospital death predictors: age (OR = 1.028, 95% CI = 1.014 to 1.043, P < 0.001).

Conclusion

We demonstrated that the CRP/albumin ratio, a possible marker of residual inflammation, in addition to classical variables, could be a useful and objective tool to support the clinical judgment on the ICU discharge decision process. The best value of the CRP/albumin ratio to predict death after ICU discharge is 2. Further prospective investigations are necessary to confirm these findings.