Assessing Malnutrition Risk and CT-Defined Muscle Quality in Older Emergency Laparotomy Patients

Aims
Older patients undergoing emergency colorectal surgery are at high risk of adverse outcomes, yet nutritional screening tools may not capture vulnerability. This study evaluated whether malnutrition risk identified using the Malnutrition Universal Screening Tool (MUST) and muscle quality, assessed by CT-defined psoas muscle density, were associated with 60-day postoperative mortality.

Methods
A retrospective observational study was conducted at a UK hospital. Patients aged ≥65 years who underwent emergency laparotomy in a 12-month period were included. MUST scores were extracted from clinical records and psoas muscle density (Hounsfield Units, HU) was measured at L3 preoperatively. Associations between muscle quality, MUST category (low vs medium/high) and 60-day mortality were assessed using χ2 and logistic regression with age and sex as covariates.

Results
In 141 patients (mean age 76.6 years; 46.1% male), 64.5% were classified as medium/high MUST risk with 60-day mortality of 20.6%. In adjusted models, both MUST and psoas muscle density were independently associated with 60-day mortality (p=0.037 for MUST; p=0.003 for muscle density). Patients with medium/high risk MUST scores had higher odds of mortality compared with low-risk patients (adjusted OR 1.85, 95% CI 1.04-3.29). Lower psoas muscle density was associated with increased mortality (adjusted OR 0.911 per 1- unit HU), where each unit increase in muscle density was associated with an 8.9% reduction in mortality odds.

Conclusion
Older patients presenting for surgery with higher MUST or low muscle quality are at significant risk of mortality at 60 days, demonstrating the importance of early perioperative risk identification.