Introduction: Preoperative risk stratification in older adults is a key component for reducing postoperative morbidity and mortality, given the high prevalence of comorbidities, frailty, and functional impairment in this population. However, commonly used risk assessment tools show limited predictive performance when applied to geriatric patients. Objective: To validate a preoperative assessment scale for predicting postoperative morbidity and mortality in older adults undergoing surgical procedures. Material and Methods: An analytical case-control study nested within a cohort of patients aged 65 years and older undergoing surgery was conducted. The scale was developed using clinical, functional, and laboratory variables selected through logistic regression analysis. Predictive performance was assessed using receiver operating characteristic (ROC) curves, along with sensitivity, specific...