慢性心不全のサルコペニア

慢性心不全患者のサルコペニアに関する論文を紹介します。

Susann Fülster, et al. Muscle wasting in patients with chronic heart failure: results from the studies investigating co-morbidities aggravating heart failure (SICA-HF). Eur Heart J (2012) doi: 10.1093/eurheartj/ehs381 First published online: November 23, 2012

対象は200人の慢性心不全患者で、筋肉量はDEXAで評価しています。筋肉量が若年の2SD以下の場合にサルコペニアと診断しています。研究デザインは横断研究です。

結果ですが、サルコペニアは39人（19.5％）に認めました。サルコペニア群ではサルコペニアを認めない群と比較して、握力、大腿四頭筋筋力、最大酸素消費量、下肢運動時間、左室駆出率、6分間歩行距離、歩行速度が有意に低く、IL-6が有意に高かったです。

多変量解析では、サルコペニアは最大酸素消費量と独立した関連を認めました。以上より、慢性心不全ではサルコペニアを認めることがあり、サルコペニアの場合には運動能力や筋力の低下を認めるという結論です。

慢性心不全患者のサルコペニアは、日本ではもっと多い印象があります。この研究では筋肉量低下のみでサルコペニアと診断していますが、筋力低下、身体機能低下を含めて診断しても、割合は大差なかったのではと推測します。悪液質の有病割合も知りたかったですね。

Abstract

Aims To assess the prevalence and clinical impact of reductions in the skeletal muscle mass of patients with chronic heart failure (HF). Chronic HF is accompanied by co-morbidities that influence the quality of life and outcomes.

Methods and results We prospectively enrolled 200 patients with chronic HF. The appendicular skeletal muscle mass of the arms and the legs combined, was assessed by dual energy X-ray absorptiometry. We analysed the muscle strength in arms and legs, and all patients underwent a 6-min walk test, a 4-m walk test, and spiroergometry testing. Muscle wasting was defined as the appendicular muscle mass 2 SD below the mean of a healthy reference group of adults aged 18–40 years, as suggested for the diagnosis of muscle wasting in healthy ageing (sarcopenia). Muscle wasting was detected in 39 (19.5%) subjects. Patients with muscle wasting had significantly lower values for handgrip and quadriceps strength as well as lower total peak oxygen consumption (peakVO_2, 1173 ± 433 vs. 1622 ± 456 mL/min), lower exercise time (7.7 ± 3.8 vs. 10.22 ± 3.0 min, both P < 0.001), and lower left ventricular ejection fraction (LVEF, P = 0.05) than patients without.

The distance walked during 6 min and the gait speed during the 4-m walk were lower in patients with muscle wasting (both P < 0.05). Serum levels of interleukin-6 were significantly elevated in patients with muscle wasting (P = 0.001). Logistic regression showed muscle wasting to be independently associated with reduced peak VO2 adjusted for age, sex, New York Heart Association class, haemoglobin, LVEF, distance walked in 6 minutes, and the number of co-morbidities (odds ratio 6.53, p = 0.01).

Conclusion Muscle wasting is a frequent co-morbidity among patients with chronic HF. Patients with muscle wasting present with reduced exercise capacity and muscle strength, and advanced disease.