Validation of predisposition, infection, response and organ dysfunction score compared with standard severity scores in predicting hospital outcome in septic shock patients.

BACKGROUND: The aim of this study was to validate and compare the performance of Simplified Acute Physiology Score 3 Predisposition, Infection, Response and Organ failure (SAPS 3 PIRO) score with Acute Physiology and Chronic Health Evaluation (APACHE) II, SAPS II and SAPS 3 scores in predicting hospital outcome in septic shock patients.

METHODS: A prospective cohort study was conducted over a six-year period in the mixed medical-coronary care unit of a tertiary referral university teaching hospital. The performance of the severity scores was evaluated by discrimination, calibration and overall performance.

RESULTS: Eight hundred and eighty patients with septic shock were enrolled. Hospital mortality rate was 57.4%. Community-acquired infections accounted for 57.2%. The SAPS 3 PIRO showed the best discrimination with an area under the receiver operating characteristic curve (AUC) of 0.863 (95% confidence intervals, 0.838-0.889). The AUC of SAPS 3 PIRO score was statistically greater than APACHE II (0.82, P=0.001), SAPS II (0.819, P=0.001) and SAPS 3 (0.817, P=0.003). The calibration of all scores was poor, with the Hosmer-Lemeshow (H-L) goodness-of-fit H and C statistics <0.05. The SAPS 3 PIRO score was the best overall performance by a Brier score of 0.167.

CONCLUSION: The SAPS 3 PIRO score provided better discrimination than the APACHE II, SAPS II and SAPS 3 but had poor calibration in our septic shock patients. SAPS 3 PIRO could be used regarding risk stratification in septic shock patients, however, this score needed to be adapted and modified with new parameters for improving the performance.