Sarcopenia Predicts Postoperative Cognitive Impairment and Poor Surgical Outcomes in Older Adults: A Prospective Cohort Study.

BACKGROUND

Sarcopenia is a progressive skeletal muscle disorder prevalent in older adults, yet its role as a risk factor for acute postoperative cognitive decline-an early manifestation within the spectrum of perioperative neurocognitive disorders (PND)-remains underexplored. We hypothesize that preoperative sarcopenia increases the incidence of early postoperative cognitive impairment and adverse surgical outcomes in geriatric patients.

METHODS

This prospective cohort study enrolled 443 older adult patients (mean age 72.8 ± 5.8 years, 58.3% male) undergoing elective noncardiac surgery at a single centre in China.

Preoperative sarcopenia was diagnosed according to the 2019 Asian Working Group for Sarcopenia (AWGS) criteria, which included assessments of muscle mass, strength, and physical performance. Neurocognitive function was assessed via the Mini-Mental State Examination (MMSE) 1 day before and 3 days after surgery, with acute cognitive decline defined as a postoperative decrease of ≥ 2 points.

Of the 443 patients, 391 (88.2%) completed 6-month telephone follow-up for assessment of longer-term functional outcomes. In an exploratory subset of 60 patients, preoperative faecal samples underwent 16S rRNA sequencing and untargeted metabolomics to characterize gut microbial and metabolic signatures.

RESULTS

The prevalence of preoperative sarcopenia was 28.0% (124/443).

Acute postoperative cognitive decline occurred in 27.3% (121/443) of patients. Multivariate logistic regression identified preoperative sarcopenia (adjusted OR = 3.291; 95% CI: 1.295-7.531; p < 0.001) and frailty (adjusted OR = 4.012; 95% CI: 1.854-8.456; p < 0.001) as independent risk factors for acute cognitive decline.

Sarcopenic patients exhibited significantly higher rates of postoperative complications (adjusted RR = 1.21; 95% CI: 1.12-1.44; p = 0.025) and ICU admission (adjusted RR = 2.41; 95% CI: 1.03-4.41; p = 0.008). Among the 391 patients with complete 6-month follow-up, the sarcopenia group exhibited elevated risks of falls (adjusted RR = 2.89; 95% CI: 1.55-5.08; p = 0.028) and all-cause mortality (adjusted RR = 3.07; 95% CI: 1.17-7.87; p = 0.016).

Exploratory microbiome analysis revealed an elevated Firmicutes/Bacteroidetes ratio, reduced Bacteroides abundance, and upregulated faecal stercobilin and estradiol derivatives in sarcopenic patients who developed cognitive decline.

CONCLUSION

Preoperative sarcopenia is an independent risk factor for acute postoperative cognitive impairment and poor surgical outcomes in older adults. These findings support the integration of sarcopenia screening into preoperative risk stratification and suggest a potential role of the gut-muscle-brain axis in perioperative neurocognitive vulnerability.