Jassal Simerjot K, Wassel Christina L, Laughlin Gail A, Barrett-Connor Elizabeth, Rifkin Dena E, Ix Joachim H
Primary Care Service, VA San Diego Healthcare System, San Diego, California; Division of General Internal Medicine, Department of Medicine, University of California, San Diego, La Jolla, California.
Division of Epidemiology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
J Ren Nutr. 2015 Mar;25(2):97-102. doi: 10.1053/j.jrn.2014.07.005. Epub 2014 Sep 11.
To determine whether a previously developed and externally validated equation using common variables (demographics and weight) that are important determinants of muscle mass to estimate 24-hour urine creatinine excretion rate (eCER) is associated with muscle mass and whether spot urine creatinine (UCr) provides similar estimates of muscle mass.
Observational cross-sectional cohort study.
The Rancho Bernardo Study, San Diego, California.
A total of 1,371 Caucasian, middle class, community-dwelling older adults.
Morning spot UCr and fat-free mass (FFM) by dual-energy x-ray absorptiometry were measured. eCER was calculated: eCER (mg/day) = 879.89 + 12.51 × weight (kilogram) - 6.19 × age + 34.51 if black - 379.42 if female. Pearson correlation coefficients and linear regression were used to determine strengths of association of eCER and spot UCr with FFM.
Mean age was 70 years, and 58% were women. eCER was strongly correlated with FFM (r = 0.95, P < .001), a correlation that was superior to that of spot UCr (r = 0.40, P < .001).
An equation incorporating age, weight, sex, and race to estimate eCER is highly correlated with FFM in community-dwelling older persons and provides a more precise estimate than spot UCr. A simple screening tool for sarcopenia in older persons may allow interventions to maintain or improve muscle mass. Future studies should evaluate whether eCER predicts sarcopenia-related frailty and mortality in older persons.
确定一个先前开发并经过外部验证的方程，该方程使用肌肉量的重要决定因素（人口统计学和体重）来估计24小时尿肌酐排泄率（eCER），是否与肌肉量相关，以及随机尿肌酐（UCr）是否能提供类似的肌肉量估计值。
观察性横断面队列研究。
加利福尼亚州圣地亚哥的兰乔贝纳多研究。
总共1371名白人、中产阶级、居住在社区的老年人。
通过双能X线吸收法测量晨尿随机UCr和去脂体重（FFM）。计算eCER：eCER（毫克/天）=879.89 + 12.51×体重（千克） - 6.19×年龄 + 34.51（如果是黑人） - 379.42（如果是女性）。使用Pearson相关系数和线性回归来确定eCER和随机UCr与FFM的关联强度。
平均年龄为70岁，58%为女性。eCER与FFM高度相关（r = 0.95，P <.001），这种相关性优于随机UCr（r = 0.40，P <.001）。
一个纳入年龄、体重、性别和种族来估计eCER的方程与居住在社区的老年人的FFM高度相关，并且比随机UCr提供更精确的估计值。一种用于老年人肌肉减少症的简单筛查工具可能有助于采取干预措施来维持或改善肌肉量。未来的研究应评估eCER是否能预测老年人与肌肉减少症相关的衰弱和死亡率。
