Background

Perforated peptic ulcer (PPU) causes peritonitis and requires surgery based on disease severity. This study aimed to develop and validate a severity scale for PPU with generalized peritonitis.

Materials and methods

This retrospective cohort study used a nationwide multi-center surgical database (2013-2020). Patients aged >15 years who underwent surgery for PPU with generalized peritonitis were included and categorized into the derivation (2013-2018) and two validation (2019 and 2020) cohorts. Possible severity predictors were selected via a literature review, and Lasso models were developed to predict severe postoperative adverse events with 2000 bootstrapping. Final variables for the scoring system were determined based on inclusion frequency (≥90%) in the Lasso models. Discrimination and accuracy were evaluated using c-statistics and calibration plots. Cutoff values for minimal postoperative adverse events were examined using negative predictive values.

Results

Among 12,513 patients included (1,202 underwent laparoscopic surgery), 533 (5.9%), 138 (7.6%), and 117 (6.9%) in the derivation and two validation cohorts experienced postoperative adverse events. Age, dyspnea at rest, preoperative sepsis, III/IV/V of American Society of Anesthesiologists physical status, and albumin and creatinine were selected for the final model. A 0-11 scoring system was developed with c-statistics of 0.812-0.819. Cutoff value was determined as 5, which predicted <3% probability of postoperative adverse events regardless of type of surgery.

Conclusions

A score of <5 predicts minimal risks for postoperative adverse events and therefore would be clinically useful to determine type of surgery. Further studies are needed to validate the score.