Development and Validation of HAS (Hajibandeh Index, ASA Status, Sarcopenia) - A Novel Model for Predicting Mortality After Emergency Laparotomy.

Objectives: To develop and validate a predictive model to predict the risk of postoperative mortality after emergency laparotomy taking into account the following variables: age, age ≥ 80, ASA status, clinical frailty score, sarcopenia, Hajibandeh Index (HI), bowel resection, and intraperitoneal contamination.

Summary Background Data: The discriminative powers of the currently available predictive tools range between adequate and strong; none has demonstrated excellent discrimination yet.

Methods: The TRIPOD and STROCSS statement standards were followed to protocol and conduct a retrospective cohort study of adult patients who underwent emergency laparotomy due to non-traumatic acute abdominal pathology between 2017 and 2022. Multivariable binary logistic regression analysis was used to develop and validate the model via two protocols (Protocol A and B). The model performance was evaluated in terms of discrimination (ROC curve analysis), calibration (calibration diagram and Hosmer-Lemeshow test), and classification (classification table).

Results: One thousand forty-three patients were included (statistical power = 94%). Multivariable analysis kept HI (Protocol-A: P =0.0004; Protocol-B: P =0.0017), ASA status (Protocol-A: P =0.0068; Protocol-B: P =0.0007), and sarcopenia (Protocol-A: P <0.0001; Protocol-B: P <0.0001) as final predictors of 30-day postoperative mortality in both protocols; hence the model was called HAS (HI, ASA status, sarcopenia). The HAS demonstrated excellent discrimination (AUC: 0.96, P <0.0001), excellent calibration ( P <0.0001), and excellent classification (95%) via both protocols.

Conclusions: The HAS is the first model demonstrating excellent discrimination, calibration, and classification in predicting the risk of 30-day mortality following emergency laparotomy. The HAS model seems promising and is worth attention for external validation using the calculator provided. HAS mortality risk calculator https://app.airrange.io/#/element/xr3b_E6yLor9R2c8KXViSAeOSK .