維持透析患者ではAMCが大きいほどQOLと生命予後がよい

維持透析患者ではAMCが大きいほどQOLと生命予後がよいという論文を紹介します。

Nazanin Noori, et al: Mid-Arm Muscle Circumference and Quality of Life and Survival in Maintenance Hemodialysis Patients. Clin J Am Soc Nephrol 5, 2010. doi: 10.2215/CJN.02080310

この論文は下記のHPで全文見ることができます。

http://www.asn-online.org/press/files/kalantarzadehstudy.pdf

慢性腎不全、透析患者でもObesity Paradoxの報告があります。今回はLBMの代替指標としてのAMCのほうが脂肪量の代替指標としてのTSFより、QOLと生命予後との関連が強いのではという仮説を検証した論文です。

AMCが高いほどSF-36（包括的QOL指標）のmental health scaleが高いという結果でした。また、死亡のハザード比は、AMCが少ないほうから4分割したときにそれぞれ1.00, 0.86, 0.69, 0.63ということで、AMCが大きいほど死亡が少ないという結果でした。

以上より、維持透析患者ではAMCが大きいほどQOLと生命予後がよいといえます。つまり、サルコペニアの維持透析患者では、QOLと生命予後が悪いことが推測されます。それだけサルコペニア対策が重要と考えます。

Abstract

Background and objectives: Maintenance hemodialysis (MHD) patients with larger body or fat mass have greater survival than normal to low mass. We hypothesized that mid-arm muscle circumference (MAMC), a conveniently measured surrogate of lean body mass (LBM), has stronger association with clinical outcomes than triceps skinfold (TSF), a surrogate of fat mass.

Design, settings, participants, & measurements: The associations of TSF, MAMC, and serum creatinine, another LBM surrogate, with baseline short form 36 quality-of-life scores and 5-year survival were examined in 792 MHD patients. In a randomly selected subsample of 118 subjects, LBM was measured by dual-energy x-ray absorptiometry.

Results: Dual-energy x-ray absorptiometry–assessed LBM correlated most strongly with MAMC and serum creatinine. Higher MAMC was associated with better short form 36 mental health scale and lower death hazard ratios (HRs) after adjustment for case-mix, malnutrition-inflammation-cachexia syndrome, and inflammatory markers. Adjusted death HRs were 1.00, 0.86, 0.69, and 0.63 for the first to fourth MAMC quartiles, respectively. Higher serum creatinine and TSF were also associated with lower death HRs, but these associations were mitigated after multivariate adjustments. Using median values of TSF and MAMC to dichotomize, combined high MAMC with either high or low TSF (compared with low MAMC/TSF) exhibited the greatest survival, i.e., death HRs of 0.52 and 0.59, respectively.

Conclusions: Higher MAMC is a surrogate of larger LBM and an independent predictor of better mental health and greater survival in MHD patients. Sarcopenia-correcting interventions to improve clinical outcomes in this patient population warrant controlled trials.