Relationship between lower-limb muscle strength and functional independence among elderly people according to frailty criteria: a cross-sectional study

CONTEXT AND OBJECTIVE: Muscle strength and functional independence are considered to be determinants of frailty levels among elderly people. The aim here was to compare lower-limb muscle strength (LLMS) with functional independence in relation to sex, age and number of frailty criteria, and to ascertain the influence of these variables on elderly outpatients' independence.DESIGN AND SETTING: Quantitative cross-sectional study, in a tertiary hospital.METHODS: The study was conducted on 150 elderly outpatients of both sexes who were in a cognitive condition allowing oral communication, between October 2005 and October 2007. The following instruments were used: five-times sit-to-stand test (FTSST), Functional Independence Measurement (FIM) and Lawton's Instrumental Activities of Daily Living Scale (IADL). Descriptive, comparative, multivariate, univariate and Cronbach alpha analyses were performed.RESULTS: The mean time taken in the FTSST was 21.7 seconds; the mean score for FIM was 82.2 and for IADL was 21.2; 44.7% of the subjects presented 1-2 frailty criteria and 55.3% > 3 criteria. There was a significant association between LLMS and functional independence in relation to the number of frailty criteria, without homogeneity regarding sex and age. Functional independence showed significant influence from sex and LLMS.CONCLUSION: Elderly individuals with 1 or 2 frailty criteria presented greater independence in all FTSST scores. The subjects with higher LLMS presented better functional independence.研究背景与目的：肌肉力量与功能独立性被视为老年人衰弱程度的关键决定因素。本研究旨在比较下肢肌肉力量（lower-limb muscle strength, LLMS）与功能独立性在性别、年龄及衰弱条目数维度上的差异，并明确上述变量对老年门诊患者功能独立性的影响。 研究设计与研究场所：本研究为三级医院开展的定量横断面研究。 研究方法：本研究纳入2005年10月至2007年10月期间，150名具备口头沟通认知能力的男女老年门诊患者。本研究采用以下评估工具：五次坐站试验（five-times sit-to-stand test, FTSST）、功能独立性评定量表（Functional Independence Measurement, FIM）以及劳顿日常生活工具活动量表（Lawton's Instrumental Activities of Daily Living Scale, IADL）。研究开展了描述性分析、比较性分析、多变量分析、单变量分析及克朗巴赫α信度分析。 研究结果：五次坐站试验的平均耗时为21.7秒；功能独立性评定量表平均得分为82.2分，日常生活工具活动量表平均得分为21.2分；44.7%的受试者存在1~2项衰弱条目，55.3%的受试者存在3项及以上衰弱条目。下肢肌肉力量与功能独立性之间存在显著关联，且该关联与衰弱条目数相关，但在性别与年龄层面未呈现同质性。功能独立性显著受性别与下肢肌肉力量的影响。 研究结论：存在1~2项衰弱条目的老年个体，其各项坐站试验评分对应的功能独立性更强。下肢肌肉力量更高的受试者，功能独立性也更佳。