Cognitive Impairment as an Effect Modifier of Perioperative Risk in Elderly Patients Undergoing Lumbar Fusion Surgery.

Abstract

A retrospective study. To identify perioperative risk factors with differential impacts under varying preoperative cognitive states in elderly patients (≥75 y) undergoing lumbar fusion and to investigate whether cognitive function exerts an effect-modifying role on the risk of major postoperative complications. Cognitive impairment is a risk factor for elderly patients undergoing lumbar fusion and is difficult to improve with short-term interventions; however, how other risk factors affect surgical outcomes in the presence of cognitive impairment remains unclear. According to the education-adjusted Mini-Mental State Examination, Elderly patients who underwent lumbar fusion surgery were categorized into a cognitive impairment group (CI) and a non-cognitive impairment group (Non-CI). Postoperative outcomes were compared between groups, and multivariable regression analyses were performed to explore independent risk factors for major complications under different cognitive states. Interaction models were subsequently constructed to evaluate the effect-modifying role of cognitive status on candidate risk factors. Among 186 Non-CI patients and 57 CI patients, the incidence of major postoperative complications was significantly higher in the CI group (42.1% vs. 33.9%, P=0.023). In the overall cohort, cognitive impairment (AOR 0.89, 95% CI 0.83-0.95, P<0.001) were identified as independent risk factors for major complications. Interaction analyses confirmed significant interactions between cognitive impairment and diabetes, frailty, and intraoperative transfusion volume. Preoperative cognitive impairment is not only an independent risk factor for major postoperative complications in elderly patients undergoing lumbar fusion but also functions as an effect modifier that significantly amplifies the impact of frailty, diabetes, and intraoperative transfusion volume on outcomes. III.