Royal Brompton and Harefield NHS Foundation Trust and Imperial College, London.
Eur Respir J. 2014 May;43(5):1298-305. doi: 10.1183/09031936.00088113. Epub 2013 Oct 31.
Usual gait speed is a consistent predictor of adverse outcomes in community-dwelling elderly people. The reliability and validity of the 4-m gait speed (4MGS) has recently been demonstrated in patients with chronic obstructive pulmonary disease (COPD). The aims of this study were to assess the responsiveness of the 4MGS and to estimate the minimal clinically important difference (MCID). In 301 COPD patients, 4MGS and incremental shuttle walk (ISW) were measured before and after pulmonary rehabilitation. 4MGS and ISW were also measured at baseline and 1 year later in a separate cohort of 162 COPD patients. The MCID of 4MGS was estimated using distribution and anchor-based methods. 4MGS improved significantly with pulmonary rehabilitation (mean change 0.08 m·s(-1), p<0.001). The minimal detectable change at 95% confidence was 0.11 m·s(-1). The MCID was estimated at 0.11 m·s(-1) (anchored against ISW) and 0.08 m·s(-1) (anchored against self-reported improvement). The effect size for 4MGS was greatest in frail individuals. After 12 months, mean 4MGS declined by 0.04 m·s(-1). When anchored against a decline of more than the MCID for ISW, change in 4MGS was -0.11 m·s(-1). The 4MGS is responsive to pulmonary rehabilitation and longitudinal change in COPD, and has potential as a simple functional assessment tool in COPD. The 4MGS may be particularly useful in frail individuals with COPD.
常速步行是社区居住的老年人不良预后的一致预测因素。4 米步行速度（4MGS）的可靠性和有效性最近已在慢性阻塞性肺疾病（COPD）患者中得到证实。本研究的目的是评估 4MGS 的反应能力，并估计最小临床重要差异（MCID）。在 301 例 COPD 患者中，在肺康复前后测量了 4MGS 和递增穿梭步行（ISW）。在另一组 162 例 COPD 患者中，还在基线和 1 年后测量了 4MGS 和 ISW。使用分布和基于锚的方法估计了 4MGS 的 MCID。肺康复后 4MGS 显著改善（平均变化 0.08 m·s(-1)，p<0.001）。95%置信区间的最小可检测变化为 0.11 m·s(-1)。MCID 估计为 0.11 m·s(-1)（与 ISW 相关）和 0.08 m·s(-1)（与自我报告的改善相关）。4MGS 的效应大小在脆弱个体中最大。12 个月后，4MGS 的平均水平下降了 0.04 m·s(-1)。当与 ISW 的 MCID 以上的下降相关时，4MGS 的变化为-0.11 m·s(-1)。4MGS 对肺康复和 COPD 的纵向变化具有反应能力，并且可能成为 COPD 的简单功能评估工具。4MGS 可能对患有 COPD 的脆弱个体特别有用。
