To determine the incidence of in-hospital postoperative mortality and validate the Preoperative Score to Predict Postoperative Mortality (POSPOM).

Retrospective case–control study.

A tertiary university hospital in Thailand.

All patients who underwent surgical procedures in 2019 under any anaesthesia technique.

Incidence of in-hospital postoperative mortality and POSPOM score performance (sensitivity, specificity and predictive values).

A total of 39 674 patients underwent surgery in 2019. The in-hospital postoperative mortality rate was 0.76% (95% CI 0.68% to 0.85%). After excluding cases per POSPOM criteria, 270 deceased patients remained. The POSPOM score was validated against these 270 cases and 270 randomly selected survivors, yielding an area under the receiver operating characteristic curve of 0.73 (95% CI 0.69 to 0.77). At a cut-off of 21, the sensitivity was 71.5% (95% CI 65.7% to 76.8%), and the specificity was 61.9% (95% CI 55.8% to 67.7%).

This single-centre study found a low in-hospital postoperative mortality rate. The POSPOM score demonstrated moderate predictive accuracy for postoperative mortality risk and may be useful for preoperative risk stratification.

https://www.thaiclinicaltrials.org/show/TCTR20200330001.