Objective radiologic assessment of body composition in patients with end-stage liver disease: going beyond the BMI.

BACKGROUND: Body mass index (BMI) is a commonly used but likely inexact measure of body composition for patients with end-stage liver disease. For this reason, we examined whether body composition measurements from direct visualization on computed tomography (CT) scans provide new insights in both the degree of malnutrition and the discordant combinations such as obesity with muscle mass loss. This technology is widely used in other medically ill populations but not yet in liver transplantation.
METHODS: We examined actual body composition using abdominal CT scan data and software designed to measure fat and muscle compartments.
RESULTS: In 234 liver transplant candidates, we found that BMI was highly and significantly correlated to subcutaneous and visceral fat. However, we additionally found that, even among obese patients, cachexia, as defined by muscle mass, was common, with 56% of those with BMI above 30 being cachexic. We also found that patients with nonalcoholic steatohepatitis, compared with other types of liver diseases, were significantly more likely to have larger amounts of visceral fat while also having less muscle. In an exploratory analysis, muscle mass corrected for height was a significant predictor of posttransplantation survival.
CONCLUSIONS: Body composition by CT scan data provides a specific method to identify obesity and muscle wasting for end-stage liver disease patients. Whether these data can aid in the prognostication of outcomes and survival requires further investigation.