image: Analyzing the Mini-Cog score as a continuous variable, it was found to have a nearly linear negative correlation with POD risk: for each 1-point increase in the score, the risk of POD decreased by 23% (unadjusted OR = 0.77, p < 0.001). Even after multi-factor adjustment (adjusting for demographic factors, preoperative comorbidities, and intraoperative factors such as intraoperative hypotension and blood transfusion), each 1-point increase still reduced the risk by 16% (OR = 0.84, p = 0.003). Furthermore, the study innovatively combined Mendelian randomization analysis, mainly based on 139 cognitive function-related SNPs in the European population. These SNPs are functionally enriched in pathways such as synaptic plasticity and neural development, suggesting that cognitive impairment and delirium may share common neural mechanisms.
Credit: Ailin Luo
The study was led by Professor Ailin Luo from Department of Anesthesiology and Pain Medicine, Hubei Key Laboratory of Geriatric Anesthesia and Perioperative Brain Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology and was funded by National Key R&D Program of China (Program No. 2020YFC2009002).
The study enrolled 2,257 patients aged 75 and older who underwent elective noncardiac and noncranial surgeries at 16 Chinese medical centers between September 2021 and November 2023. Preoperative cognitive function was assessed using the Mini-Cog test, a brief tool that combines memory and clock-drawing tasks (scores ≤2 indicate cognitive impairment). Postoperative delirium was diagnosed using the Confusion Assessment Method (CAM) or CAM-ICU for intubated patients.
Key findings from the cohort study include:
- 28.4% of patients had preoperative cognitive impairment.
- POD incidence was 9.7% overall, but reached 14.6% in those with cognitive impairment (vs. 7.7% in those without).
- Cognitive impairment was independently associated with a 2.06-fold higher POD risk in unadjusted analyses, and remained significant (OR 1.74) after accounting for demographics, comorbidities, and intraoperative factors like anesthesia type and blood loss.
- A nearly linear inverse relationship was observed: each 1-point increase in Mini-Cog score was linked to a 16% lower POD risk.
To investigate potential causality, researchers performed a two-sample MR analysis using 139 genetic variants (single nucleotide polymorphisms, SNPs) associated with cognitive performance from European ancestry datasets. The inverse-variance weighted method showed higher cognitive performance was associated with a 26% reduced delirium risk (OR 0.74, 95% CI 0.59–0.93, p=0.009), with no significant pleiotropy or heterogeneity.
“Our findings suggest preoperative cognitive screening with the Mini-Cog—simple and quick to administer—could become a valuable tool in preoperative risk assessment,” said Ailin Luo, corresponding author. “Identifying high-risk patients early may allow for targeted interventions, such as optimized anesthesia regimens or postoperative sleep support, to reduce POD incidence.”
The study notes limitations, including potential selection bias (excluding emergency surgeries and severe cognitive impairment cases) and the use of European genetic data, which may limit generalizability to Asian populations. Further research with diverse genetic datasets is needed to confirm the causal link.
See the article:
Association Between Preoperative Cognitive Performance and Postoperative Delirium in Older Patients: Results From a Multicenter, Prospective Cohort Study, and a Mendelian Randomization Study
https://doi.org/10.1002/mco2.70302
Journal
MedComm
Article Title
Association Between Preoperative Cognitive Performance and Postoperative Delirium in Older Patients: Results From a Multicenter, Prospective Cohort Study, and a Mendelian Randomization Study
Article Publication Date
17-Jul-2025