Impact of frailty, malnutrition and socioeconomic status on perioperative outcomes

Background: Frailty, malnutrition and low socioeconomic status may mutually perpetuate each other in a self-reinforcing and interdependent manner. The intertwined nature of these factors may be overlooked when investigating impacts on perioperative outcomes. This study aimed to investigate the impact of frailty, malnutrition and socioeconomic status on perioperative outcomes. Methods: A multicentre cohort study involving six Australian tertiary hospitals was undertaken. All consecutive surgical patients who underwent an operation were included. Frailty was defined by the Hospital Frailty Risk Score, malnutrition by the Malnutrition Universal Screening Tool (MUST) and low socioeconomic status by the Index of Relative Socioeconomic Disadvantage. Linear mixed-effects and binary logistic generalised estimated equation models were performed for the outcomes: inpatient mortality, length of stay, 30-day readmission and re-operation. Results: A total of 21 976 patients were included. After controlling for confounders, malnutrition and socioeconomic status, patients at high risk of frailty have a mean hospital length of stay 3.46 times longer (mean ratio = 3.46; 95% confidence interval (CI): 3.20, 3.73; P value <.001), odds of 30-day readmission 2.4 times higher (odds ratio = 2.40; 95% CI: 2.19, 2.63; P value <.001) and odds of in-hospital mortality 12.89 times greater than patients with low risk of frailty (odds ratio = 12.89; 95% CI: 4.51, 36.69; P value <.001). Elevated MUST scores were also significantly associated with worse outcomes, but to a lesser extent. Socioeconomic status had no association with outcomes. Conclusion: Perioperative risk evaluation should consider both frailty and malnutrition as separate, significant risk factors. Despite strong causal links with frailty and malnutrition, socioeconomic disadvantage is not associated with worse postoperative outcomes. Additional studies regarding the prospective identification of these patients with implementation of strategies to mitigate frailty and malnutrition and assessment of perioperative risk are required.