Prognostic Value of the Procalcitonin-to-Albumin Ratio and C-Reactive-Protein-to-Albumin Ratio for Bloodstream Infection in Patients in the Emergency Department

Background To investigate the predictive value of the procalcitonin-to-albumin ratio (PAR) and C-reactive-protein-to-albumin ratio (CAR) measured for the first time in patients with bloodstream infection (BSI). Data resources A total of 720 patients with confirmed BSI who visited the Emergency Department of West China Hospital, Sichuan University from January 1, 2017 to September 30, 2024 were enrolled. Albumin, procalcitonin and C-reactive protein levels were collected. Results A total of 505 patients (including 421 survivors and 84 non-survivors) and 215 patients (including 172 survivors and 43 non-survivors) were included in the modeling group and validation group. PAR and CAR were found to be associated with 28-day mortality in patients with BSI (logit(P) = IN [P/(1-P)]=2.02-0.34[PAR]-0.11[CAR]). For the 28-day mortality prediction models, the area under the receiver operating characteristic curve values of PAR and CAR were 0.618 (95% confidence interval [CI], 0.528–0.707) and 0.573 (95% CI, 0.470–0.676). Moreover, the models were well differentiated. Further internal validation and evaluation of the model were performed in the validation group. The mean squared error and root mean squared error of the 28-day mortality prediction model in the validation group were 0.12 and 0.34, and the coefficient of determination was 0.064. Conclusions The PAR and CAR measured for the first time in emergency can effectively predict the short-term prognosis of patients with BSI and help clinicians to accurately identify patients with poor prognosis early.