Development and validation of a novel preoperative risk stratification tool to predict one-year mortality for older patients after emergency laparotomy: the SArC calculator

Abstract Introduction: Sarcopenia and low skeletal muscle index (SMI) are associated with high major morbidity and mortality following emergency laparotomy (EL). Existing preoperative risk models often focus on short-term outcomes. This study aimed to develop a personalised preoperative score using SMI to predict 1-year mortality in older patients undergoing EL. Methods: This was a retrospective study conducted in patients aged ≥65 years who underwent EL from January 2016 to December 2022. Patients who underwent EL for trauma, vascular surgery or cholecystectomy were excluded. The cut-off values for low SMI were <33.4 and 26.3 cm 2 /m 2 for males and females, respectively. Univariate and multivariate logistic regression analyses were performed to identify the predictors of 1-year mortality. Receiver operating characteristic (ROC) curve and Hosmer–Lemeshow test were used to evaluate the model performance. Results: A total of 477 patients (training cohort: n = 334, validation cohort: n = 143) were included in the analysis. Of these patients, 41.5% had sarcopenia. The incidences of Clavien–Dindo grade III morbidity, grade IV morbidity, in-hospital mortality and 1-year mortality were 6.7%, 8.0%, 6.3% and 18.5%, respectively. Multivariate analyses showed that sarcopenia (odds ratio OR 4.42, 95% confidence interval CI 1.69–11.57), American Society of Anesthesiologists score (OR 2.37, 95% CI 1.23–4.54) and clinical frailty scale (OR 1.83, 95% CI 1.30–2.59) were independent predictors for 1-year mortality. The area under the ROC curve was 0.79 (95% CI 0.71–0.88) and 0.73 (95% CI 0.58–0.87) in the training and validation cohorts, respectively. Hosmer–Lemeshow test was not statistically significant. Conclusion: We developed an easy-to-use preoperative calculator to predict 1-year mortality in older patients undergoing EL.