Journal of Cachexia, Sarcopenia and Muscle悪液質レビュー論文

Journal of Cachexia, Sarcopenia and Muscleの中から、悪液質に関するレビュー論文を紹介します。

Stephan von Haehling, and Stefan D. Anker: Cachexia as a major underestimated and unmet medical need: facts and numbers. Journal of Cachexia, Sarcopenia and Muscle Volume 1, Number 1, 1-5, DOI: 10.1007/s13539-010-0002-6

下記のHPで全文PDFを見ることができます。

http://www.springerlink.com/content/d20477631090189w/fulltext.pdf

悪液質は見逃されていることがよくあります。がん、慢性心不全（CHF）、慢性腎臓病（CKD）、COPD、関節リウマチ、アルツハイマー病、感染症（慢性）、その他の慢性疾患の結果、悪液質を認めることがあります。日本ではがんによる悪液質以外、関心が低いのが現状です。

すべての疾患による悪液質の有病割合は約1％と推定されています。つまり、日本では約120万人が悪液質の状態にあるといえます。悪液質は3-12ヶ月以内での5％以上の体重減少に加え、骨格筋減少、疲労、検査値異常（貧血、炎症、低アルブミン）などの存在で診断することができます（Evans, 2008）。下記に詳細を示します。

悪液質の原因疾患の存在
12ヶ月以内に5％以上の体重減少（or BMI<20）>0.5、Hb<12.0、Alb<3.2）
（Evans WJ, et al: Cachexia: A new definition, Clinical Nutrition , 2008)

がん以外の悪液質の原因疾患で特に問題となっているのは、COPD、CKD、CHFです。悪液質の状態にある患者の1年以内の死亡率はおよそ、COPDで10-15％、CHFとCKDで20-30％、がんで80％です。

繰り返しになりますが、悪液質と飢餓はどちらも低栄養ですが、別の概念です。飢餓と侵襲と悪液質を区別しないで単に低栄養ということで一緒にしているうちは、悪液質を見過ごしてしまう可能性が高いです。Evansらの診断基準、もしくは前悪液質の診断基準できちんと悪液質の有無を判断することが大切です。

前悪液質の診断基準：下記の4項目をすべて満たす
　悪液質の原因となる慢性疾患の存在
　6ヶ月以内に5％以上の体重減少
　慢性・再発性の全身炎症反応（CRP陽性）→0.5でも陽性と考えます。
　食思不振もしくは食思不振に関連した症状
Muscaritoli M, et al: Consensus definition of sarcopenia, cachexia and pre-cachexia: joint document elaborated by Special Interest Groups (SIG) "cachexia-anorexia in chronic wasting diseases" and "nutrition in geriatrics". Clinical Nutrition. 29(2):154-159, 2010

Abstract
Cachexia is a serious, however underestimated and underrecognised medical consequence of malignant cancer, chronic heart failure (CHF), chronic kidney disease (CKD), chronic obstructive pulmonary disease (COPD), cystic fibrosis, rheumatoid arthritis, Alzheimer's disease, infectious diseases, and many other chronic illnesses. The prevalence of cachexia is high, ranging from 5% to 15% in CHF or COPD to 60% to 80% in advanced cancer. By population prevalence, the most frequent cachexia subtypes are in order: COPD cachexia, cardiac cachexia (in CHF), cancer cachexia, and CKD cachexia. In industrialized countries (North America, Europe, Japan), the overall prevalence of cachexia (due to any disease) is growing and currently about 1%, i.e., about nine million patients. The relative prevalence of cachexia is somewhat less in Asia, but is a growing problem there as well. In absolute terms, cachexia is, in Asia (due to the larger population), as least as big a problem as in the Western world. Cachexia is also a big medical problem in South America and Africa, but data are scarce. A consensus statement recently proposed to diagnose cachexia in chronic diseases when there is weight loss exceeding 5% within the previous 3–12 months combined with symptoms characteristic for cachexia (e.g., fatigue), loss of skeletal muscle and biochemical abnormalities (e.g., anemia or inflammation). Treatment approaches using anabolics, anti-catabolic therapies, appetite stimulants, and nutritional interventions are under development. A more thorough understanding of the pathophysiology of cachexia development and progression is needed that likely will lead to combination therapies being developed. These efforts are greatly needed as presence of cachexia is always associated with high-mortality and poor-symptom status and dismal quality of life. It is thought that in cancer, more than 30% of patients die due to cachexia and more than 50% of patients with cancer die with cachexia being present. In other chronic illnesses, one can estimate that up to 30% of patients die with some degree of cachexia being present. Mortality rates of patients with cachexia range from 10% to 15% per year (COPD), to 20% to 30% per year (CHF, CKD) to 80% in cancer.