Long-Term Cognitive and Functional Outcomes Following Postoperative Delirium and Liberal Fluid Fasting in Elderly Trauma Patients: A Prospective Single-Centre Study

Background: Postoperative delirium (POD) is a frequent and serious complication in elderly surgical patients. Liberalising preoperative fluid fasting has been shown to reduce its incidence. However, evidence on long-term cognitive and functional outcomes following POD or liberal fluid fasting remains limited. Objectives: This study investigates whether POD and different fluid fasting regimens are associated with changes in cognitive performance and activities of daily living twelve months after surgery. Methods: As a follow-up to the prospective ‘LFFgertrud’ trial, 89 geriatric patients were contacted by phone twelve months after elective trauma or orthopaedic surgery (March 2023–February 2024). Participants completed four validated questionnaires assessing cognition and everyday functioning: the Short Blessed Test (SBT), EQ-5D-5L, Barthel index (BI), and the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE). Results: The hypotheses regarding the effects of POD and fluid fasting on cognitive and functional outcomes were not statistically supported. In contrast, neurodegenerative disease was strongly associated with poorer outcomes in three of the four follow-up measures (SBT: β = 1.27, p = 0.01; EQ-5D-5L: β = 1.43, p < 0.001; BI: β = −1.63, p < 0.001), and polymedication also emerged as a relevant predictor. Although not statistically significant, descriptive trends indicated that patients who developed POD showed lower cognitive performance and reduced quality of life at twelve months. Conclusions: POD and fluid fasting duration were not significantly associated with long-term cognitive or functional outcomes one year after hospitalisation. The findings highlight the importance of considering pre-existing neurocognitive disease and polypharmacy when assessing the risk of adverse long-term outcomes in older patients. Due to the multifactorial nature of recovery in this population, further research involving larger sample sizes is required in order to gain a better understanding of the factors that influence long-term outcomes.