MORTALITY PREDICTORS AFTER MAJOR ABDOMINAL SURGERY IN PATIENTS AGED 80 AND OVER: THE ROLE OF FRAILTY AND PHYSIOLOGICAL RESERVE
Introduction: Patients aged 80 years or older undergoing major abdominal surgery represent a high-risk group with substantial postoperative mortality. Frailty and reduced physiological reserve are key determinants of adverse outcomes; however, data focusing specifically on this population are limited. This study aimed to identify predictors of 30-day mortality, with emphasis on frailty and physiological reserve. Materials and Method: This retrospective single-center cohort study included patients aged 80 years or older who underwent major abdominal surgery between 2021 and 2025. Frailty was assessed using the five-item modified frailty index. Physiological reserve was evaluated using preoperative albumin, hemoglobin, and creatinine levels. The primary outcome was 30-day mortality. Multivariable logistic regression analysis was performed. Results: A total of 92 patients were included, with a 30-day mortality rate of 18.5%. Emergency surgery was more frequent among non-survivors (70.6% vs. 12.0%, p<0.001), as was preoperative sepsis (33.3% vs. 4.0%, p=0.003). Severe frailty was present in 50.0% of non-survivors compared to 14.9% of survivors (p=0.025). Non-survivors had lower albumin levels (28.4 vs. 37.0 g/L, p=0.001). In the multivariable analysis, frailty was an independent predictor of mortality (odds ratio 2.71, 95% confidence interval 1.03–7.16, p=0.044). Albumin showed a trend toward significance (odds ratio 0.87 per unit increase, p=0.069). The model demonstrated high discriminative ability (area under the curve 0.899). Conclusion: Frailty is an independent predictor of 30-day mortality in patients aged 80 years or older undergoing major abdominal surgery. Incorporating frailty assessment into routine preoperative evaluation may improve risk stratification and clinical decision-making. Keywords: Frailty; Octogenarians; Nonagenarians; Mortality; Surgical Oncology; General Surgery