Clinical Significance of Short-term Change and Variability of Grip Strength

描述（由申请人提供）：衰老与骨骼肌质量和力量的进行性损失相关，称为肌肉减少症，是残疾、虚弱和死亡的重要风险因素。流行病学上，基于单次测量握力定义的肌无力已多次被证明与随后的不良健康结果相关，即使在中年测量以预测数十年后的身体残疾。这些发现导致了持续的努力，以确定临床上有意义的切割点的肌肉力量 在肌肉减少症的诊断和越来越多的兴趣，使用握力作为一个关键终点，在临床试验的新干预措施的脆弱。然而，这些努力的成功需要在两个领域提高知识。首先，单一的实力衡量是否能够充分捕捉潜在的风险？其次，鉴于大多数试点试验的随访时间较短，通常为6个月，因此了解短期内可检测变化的程度和异质性以及此类变化与长期健康结局的临床相关性非常重要。到目前为止，这些主题尚未在纵向环境中得到充分研究。中心假设是，握力的短期轨迹，其特征在于握力的变化率和人内变异性，预测老年人的握力和不良健康结果的长期轨迹。为了验证这一假设，本项目建议评估：（i）握力短期（6个月）轨迹的异质性，（ii）握力短期轨迹对健康结果长期（3年）轨迹的影响，以及（iii）多系统生理失调对握力短期轨迹的影响。该研究应用最先进的统计模型来分析现有的纵向数据，这些数据来自妇女健康和老龄化研究（WHAS）I的每周残疾子研究。该子研究包括102名年龄在65岁及以上的妇女，她们在6个月内每周接受一次评估，随后在1993年至1996年期间每隔6个月进行5次半年一次的随访，总随访时间为3年。

DESCRIPTION (provided by applicant): Aging is associated with progressive lose of skeletal muscle mass and strength referred to as sarcopenia, a significant risk factor for disability, fraily, and mortality. Epidemiologically, muscle weakness defined based on a single measurement of hand grip strength has repeatedly proven to correlate with subsequent adverse health outcomes, even when measured in mid-life to predict physical disability decades later. These findings have led to ongoing efforts to define clinically meaningful cut points for muscle strength in the diagnosis of sarcopenia and growing interest in using grip strength as a key endpoint in clinical trials of new interventions for frailty. However, the success of such efforts requires improved knowledge in two areas. First, whether a single measurement of strength can sufficiently capture the underlying risk? Second, given that most of the pilot trials have a short follow-up, typically 6 months; it is important to know the degree and heterogeneity of detectable change in the short term and the clinical relevance of such change to long-term health outcomes. So far, these topics have not been adequately studied in a longitudinal setting. The central hypothesis is that short term trajectory of grip strength, characterized by rate of change and intra-person variability in grip strength, predicts long term trajectory of grip strength and adverse health outcomes in older adults. To test this hypothesis, this project proposes to evaluate: (i) the heterogeneity of short-term (6-month) trajectory of grip strength, (ii) the impac of short-term trajectory of grip strength on long-term (3- year) trajectories of health outcomes, and (iii) the effect of multisystem physiological dysregulation on short-term trajectory of grip strength. The study applies state-of-the-art statistical models to analyze existing longitudinal data from the Weekly Disability Substudy of the Women's Health and Aging Study (WHAS ) I. The substudy is comprised of 102 women aged 65 years and over who were evaluated on a weekly basis over six months, followed by additional five semi-annual visits of 6 months apart for a total follow-up of three years between 1993 and 1996.