JOA - 2026-08-24 - Journal Article
Effect of Dementia on Risk Factors for Postoperative Delirium in Older Patients Undergoing Total Knee Arthroplasty: A Retrospective Cohort Study Based on a Large National Dataset.
Lin HL, Lu HT, Lee CY, Chang CY, Lin ES, Lin HC
Topics
Key Takeaway
Dementia carries an adjusted OR of 6.47 for postoperative delirium after TKA in patients ≥75 years, with a POD incidence of 20.7% vs. 2.6% in non-demented patients.
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Summary
This study examined whether dementia modulates the risk factor profile for postoperative delirium in patients ≥75 undergoing primary or revision TKA using a national dataset (2021–2023). Logistic regression with separate models for demented and non-demented patients identified dementia as an independent POD predictor (aOR 6.47, 95% CI 5.13–8.15). Risk factor profiles diverged by dementia status: smoking and functional dependency dominated in demented patients, while falls, anemia, and higher ASA class were significant only in non-demented patients, suggesting these may flag occult cognitive impairment.
Key Limitation
Reliance on administrative coding for dementia diagnosis likely underestimates true prevalence and misclassifies patients with mild cognitive impairment into the non-demented cohort, attenuating risk factor differences between groups.
Original Abstract
BACKGROUND
Postoperative delirium (POD) is a frequent and serious complication following total knee arthroplasty (TKA), particularly among older patients. Dementia is a well-established risk factor for POD. Whether dementia modulates the significance of other POD risk factors remains unclear.
METHODS
This retrospective cohort study was conducted using a large national dataset (from 2021 to 2023). Patients aged ≥ 75 years undergoing primary or revision TKA were included. Logistic regressions, adjusted for demographic, clinical, and perioperative variables, were performed to assess the association between dementia and POD risk. Separate multivariate models were used for patients who did and did not have dementia. This study cohort comprised 22,077 patients. Among them, 609 patients (2.8%) had dementia.
RESULTS
The POD incidence rate was significantly higher in patients who had dementia (20.7 versus 2.6%). Dementia was independently associated with POD (adjusted odds ratio: 6.47; 95% confidence interval: 5.13 to 8.15). In patients who had dementia, advanced age, smoking, and functional dependency were the strongest POD predictors. In patients who did not have dementia, advanced age, functional dependency, a history of falls, a higher American Society of Anesthesiologists class, and anemia were significant predictors. General anesthesia was not associated with increased POD risk in either group.
CONCLUSION
Dementia is a strong and independent predictor of POD after TKA. It modulates the significance of other risk factors. Falls, anemia, and a higher ASA class may indicate undiagnosed cognitive impairment in patients who did not have dementia. Preoperative cognitive screening among high-risk patients, combined with multidisciplinary preventive strategies, may improve surgical outcomes and optimize resource allocation.