Prevalence of pre-operative undiagnosed cognitive impairment and its association with handgrip strength, oral hygiene, and nutritional status in older elective surgical patients in Japan.

PURPOSE: Preoperative cognitive impairment is a significant factor influencing post-operative delirium. We have been performing routine pre-operative comprehensive assessments, including evaluation of cognitive function, handgrip strength, oral hygiene, and nutritional status, in patients aged ≥ 65 years since April 2021. This study aimed to examine the completion rate of pre-operative comprehensive assessment and assess the prevalence of pre-operative undiagnosed cognitive impairment.

METHODS: In this prospective observational study including patients aged ≥ 65 years scheduled for elective surgery with general or regional anesthesia, cognitive impairment was defined as a Mini-Cog score ≤ 2, and its associations with handgrip strength, oral hygiene, and nutritional status were evaluated. Oral hygiene and nutritional status were assessed using an oral frailty self-checklist and the Mini Nutritional Assessment-Short Form, respectively. The incidence of pre-operative undiagnosed cognitive impairment was estimated, and its associated factors were explored with multiple logistic regression.

RESULTS: Among 331 eligible patients, the completion rate was 97.7% (305/312). The mean age was 74.8 years, and 13.1% (40/305) (95% confidence interval [CI], 9.7-17.3%) of the patients had pre-operative undiagnosed cognitive impairment. Multiple logistic regression revealed that handgrip strength (odds ratio [OR] = 0.94, 95%CI = 0.89-0.99) and oral frailty self-checklist score (OR = 1.19, 95%CI = 1.02-1.40) were associated with pre-operative undiagnosed cognitive impairment, while the Mini Nutritional Assessment-Short Form score was not significantly associated (OR = 0.97, 95%CI = 0.82-1.14).

CONCLUSIONS: Preoperative comprehensive assessment was feasible. The prevalence of pre-operative undiagnosed cognitive impairment was 13%, and poor handgrip strength and worse oral hygiene were significantly associated factors.