関節リウマチの前悪液質と悪液質

関節リウマチ患者における新しい前悪液質と悪液質の定義の妥当性に関する論文を紹介します。

van Bokhorst-de van der Schueren MA, Konijn NP, Bultink IE, Lems WF, Earthman CP, van Tuyl LH. Relevance of the new pre-cachexia and cachexia definitions for patients with rheumatoid arthritis. Clin Nutr. 2012 Jun 11. [Epub ahead of print]

前悪液質はMuscaritoliらの診断基準、悪液質はEvansらの診断基準を用いています。103人の関節リウマチ患者で評価した結果、除脂肪体重や筋肉量が少ない患者は多かったものの、体重減少や食欲不振はあまり認めませんでした。そのため、前悪液質と悪液質の有病割合はどちらも1％でした。

確かにこれでは関節リウマチ患者の前悪液質と悪液質の診断基準としては、適当とは言えない気がします。いくらなんでも1％は低すぎという印象です。サルコペニアなら数十％になりそうですが…。Fearonらの悪液質診断基準にすれば食欲不振はありませんが、体重減少は必須となっています。

一方、筋肉量は少なくても体重減少を認めない患者を悪液質と判断してよいのかどうかも微妙です。サルコペニア、サルコペニア肥満と、前悪液質、悪液質は分けて考えたほうがよいと思いますが、どこでどう線引きをするかは、悩ましいところですね。


Abstract

BACKGROUND & AIMS:

The recently proposed definitions of 'pre-cachexia' and 'cachexia' might offer new possibilities for the detection of malnutrition in patients with rheumatoid arthritis (RA).

METHODS:

The prevalence of different components of nutritional status and the compiled definitions of 'precachexia' and 'cachexia' were measured in a cohort of 103 patients with moderately active RA. Nutritional status was determined by measuring unintentional weight loss, BMI, and muscle strength. Bio-electrical Impedance Analysis (BIA) was used to determine fat free mass index (FFMI) and fat mass index. In addition, appetite, pain, fatigue, and inflammatory activity were assessed. The prevalence of 'pre-cachexia' and 'cachexia' was calculated from different combinations of these parameters.

RESULTS:

20% of the study population had a low FFMI (<10th percentile), and 95% had a decreased muscle strength (cachexia definitions, were uncommon. The prevalence of 'pre-cachexia' and 'cachexia' was both 1% (n = 1).

CONCLUSIONS:

In spite of altered body composition and impaired body function, the recently proposed definitions of both 'pre-cachexia' and 'cachexia' were unable to identify and diagnose impaired nutritional status in RA patients mainly because of low prevalences of weight loss and decreased appetite.