終末期肝疾患のCT身体組成評価

腹部CTで終末期肝疾患の身体組成を評価した論文を紹介します。

Cruz RJ Jr, Dew MA, Myaskovsky L, Goodpaster B, Fox K, Fontes P, Dimartini A. Objective Radiologic Assessment of Body Composition in Patients with End-Stage Liver Disease: Going Beyond the BMI. Transplantation. 2013 Jan 23. [Epub ahead of print]

対象は肝移植を希望している234人の終末期肝疾患患者です。結果ですが、BMIは皮下脂肪、内臓脂肪と高い相関を認めました。しかし、筋肉量で評価した悪液質を肥満患者でもよく認めました。BMI30以上の患者の56%が悪液質でした。

非アルコール性脂肪肝炎では他の肝疾患と比較して、内臓脂肪がより多く筋肉量がより少なかったです。探索的解析では、身長で補正した筋肉量は、肝移植後の生存期間の有意な予測因子でした。腹部CTは肥満と筋肉減少の評価に有用で、予後予測にはさらなる研究が必要という結論です。

肝疾患患者で筋肉量が少ないことは、臨床的に十分納得できます。BMIでの評価だけでは不十分で、検査機器で体組成を評価すべきです。重症な肝疾患であれば必ず腹部CTを行っているでしょうから、腹部CTによる評価がルーチンとなればいいなあと思います。

Abstract

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.