Prognostic utility of serum CRP levels in combination with CURB-65 in patients with clinically suspected sepsis: a decision curve analysis.

Abstract

The prognostic utility of serum C reactive protein (CRP) alone in sepsis is controversial. We used decision curve analysis (DCA) to evaluate the clinical usefulness of combining serum CRP levels with the CUBR-65 score in patients with suspected sepsis. Retrospective cohort study. Emergency department (ED) of an urban teaching hospital in Japan. Consecutive ED patients over 15 years of age who were admitted to the hospital after having a blood culture taken in the ED between 1 January 2010 and 31 December 2012. 30-day in-hospital mortality. Data from 1262 patients were analysed for score evaluation. The 30-day in-hospital mortality was 8.4%. Multivariable analysis showed that serum CRP ≥150 mg/L was an independent predictor of death (adjusted OR 2.0; 95% CI 1.3 to 3.1). We compared the predictive performance of CURB-65 with the performance of a modified CURB-65 with that included CRP (≥150 mg/L) to quantify the clinical usefulness of combining serum CRP with CURB-65. The areas under the receiver operating characteristics curves of CURB-65 and a modified CURB-65 were 0.76 (95% CI 0.72 to 0.80) and 0.77 (95% CI 0.72 to 0.81), respectively. Both models had good calibration for mortality and were useful among threshold probabilities from 0% to 30%. However, while incorporating CRP into CURB-65 yielded a significant category-free net reclassification improvement of 0.387 (95% CI 0.193 to 0.582) and integrated discrimination improvement of 0.015 (95% CI 0.004 to 0.027), DCA showed that CURB-65 and the modified CURB-65 score had comparable net benefits for prediction of mortality. Measurement of serum CRP added limited clinical usefulness to CURB-65 in predicting mortality in patients with clinically suspected sepsis, regardless of the source.