Johansen Kirsten L, Dalrymple Lorien S, Delgado Cynthia, Kaysen George A, Kornak John, Grimes Barbara, Chertow Glenn M
United States Renal Data System Nutrition Special Studies Center, University of California, San Francisco, CA; Division of Nephrology, University of California, San Francisco, CA; Nephrology Section, San Francisco VA Medical Center, University of California, San Francisco, CA; Department of Epidemiology & Biostatistics, University of California, San Francisco, CA.
United States Renal Data System Nutrition Special Studies Center, University of California, San Francisco, CA; University of California, San Francisco Division of Nephrology, University of California, Davis, CA.
Am J Kidney Dis. 2014 Oct;64(4):600-7. doi: 10.1053/j.ajkd.2014.03.016. Epub 2014 Apr 30.
A well-accepted definition of frailty includes measurements of physical performance, which may limit its clinical utility.
In a cross-sectional study, we compared prevalence and patient characteristics based on a frailty definition that uses self-reported function to the classic performance-based definition and developed a modified self-report-based definition.
SETTING & PARTICIPANTS: Prevalent adult patients receiving hemodialysis in 14 centers around San Francisco and Atlanta in 2009-2011.
Self-report-based frailty definition in which a score lower than 75 on the Physical Function scale of the 36-Item Short Form Health Survey (SF-36) was substituted for gait speed and grip strength in the classic definition; modified self-report definition with optimized Physical Function score cutoff points derived in a development (one-half) cohort and validated in the other half.
Performance-based frailty defined as 3 of the following: weight loss, weakness, exhaustion, low physical activity, and slow gait speed.
387 (53%) patients were frail based on self-reported function, of whom 209 (29% of the cohort) met the performance-based definition. Only 23 (3%) met the performance-based definition of frailty only. The self-report definition had 90% sensitivity, 64% specificity, 54% positive predictive value, 93% negative predictive value, and 72.5% overall accuracy. Intracellular water per kilogram of body weight and serum albumin, prealbumin, and creatinine levels were highest among nonfrail individuals, intermediate among those who were frail by self-report, and lowest among those who also were frail by performance. Age, percentage of body fat, and C-reactive protein level followed an opposite pattern. The modified self-report definition had better accuracy (84%; 95% CI, 79%-89%) and superior specificity (88%) and positive predictive value (67%).
Our study did not address prediction of outcomes.
Patients who meet the self-report-based but not the performance-based definition of frailty may represent an intermediate phenotype. A modified self-report definition can improve the accuracy of a questionnaire-based method of defining frailty.
虚弱的一个被广泛接受的定义包括身体机能的测量，这可能会限制其临床应用。
在一项横断面研究中，我们基于使用自我报告功能的虚弱定义与经典的基于表现的定义，比较了患病率和患者特征，并制定了一种基于自我报告的改良定义。
2009年至2011年在旧金山和亚特兰大周边14个中心接受血液透析的成年患者。
基于自我报告的虚弱定义，即36项简短健康调查（SF - 36）身体功能量表得分低于75分替代经典定义中的步速和握力；改良的自我报告定义，其优化的身体功能得分截断点在一个开发（一半）队列中得出，并在另一半队列中进行验证。
基于表现的虚弱定义为以下情况中的3种：体重减轻、虚弱、疲惫、身体活动量低和步速缓慢。
基于自我报告功能，387名（53%）患者虚弱，其中209名（占队列的29%）符合基于表现的定义。只有23名（3%）仅符合基于表现的虚弱定义。自我报告定义的敏感性为90%，特异性为64%，阳性预测值为54%，阴性预测值为93%，总体准确率为72.5%。每千克体重的细胞内水以及血清白蛋白、前白蛋白和肌酐水平在非虚弱个体中最高，在自我报告虚弱的个体中居中，在基于表现也虚弱的个体中最低。年龄、体脂百分比和C反应蛋白水平则呈现相反的模式。改良的自我报告定义具有更好的准确性（84%；95%置信区间，79% - 89%）以及更高的特异性（88%）和阳性预测值（67%）。
我们的研究未涉及结局预测。
符合基于自我报告但不符合基于表现的虚弱定义的患者可能代表一种中间表型。改良的自我报告定义可提高基于问卷法定义虚弱的准确性。
