Catharina Hospital, Department of Vascular Surgery, Eindhoven, The Netherlands.
Catharina Hospital, Department of Vascular Surgery, Eindhoven, The Netherlands; Maastricht University, CAPHRI Research School, Maastricht, The Netherlands.
Eur J Vasc Endovasc Surg. 2016 Mar;51(3):404-9. doi: 10.1016/j.ejvs.2015.11.008. Epub 2015 Dec 20.
Disease severity and treatment outcomes in patients with intermittent claudication (IC) are commonly assessed using walking distance measured with a standardized treadmill test. It is unclear what improvement or deterioration in walking distance constitutes a meaningful, clinically relevant, change from the patients' perspective. The purpose of the present study was to estimate the minimally important difference (MID) for the absolute claudication distance (ACD) and functional claudication distance (FCD) in patients with IC.
The MIDs were estimated using an anchor based approach with a previously defined clinical anchor derived from scores of the walking impairment questionnaire (WIQ) in a similar IC population. Baseline and 3 month follow up data on WIQ scores and walking distances (ACD and FCD) were used from 202 patients receiving supervised exercise therapy from the 2010 EXITPAD randomized controlled trial. The external WIQ anchor was used to form three distinct categories: patients with "clinically relevant improvement," "clinically relevant deterioration," and "no clinically relevant change." The MIDs for improvement and deterioration were defined by the upper and lower limits of the 95% confidence interval of the mean change in ACD and FCD, for the group of IC patients that remained unchanged according to the WIQ anchor.
For the estimation of the MID of the ACD and FCD, 102 and 101 patients were included, respectively. The MID for the ACD was 305 m for improvement, and 147 m for deterioration. The MID for the FCD was 250 m for improvement, and 120 m for deterioration.
The MIDs for the treadmill measured ACD and FCD can be used to interpret the clinical relevance of changes in walking distances after supervised exercise therapy and may be used in both research and individual care.
间歇性跛行（IC）患者的疾病严重程度和治疗结果通常通过使用标准化跑步机测试测量的步行距离来评估。尚不清楚从患者角度来看，步行距离的改善或恶化多少构成了有意义的、临床相关的变化。本研究旨在估计 IC 患者绝对跛行距离（ACD）和功能跛行距离（FCD）的最小临床重要差异（MID）。
使用基于锚定的方法来估计 MID，该方法使用了来自类似 IC 人群的步行障碍问卷（WIQ）评分的先前定义的临床锚定点。使用来自 2010 年 EXITPAD 随机对照试验中接受监督运动治疗的 202 名患者的 WIQ 评分和步行距离（ACD 和 FCD）的基线和 3 个月随访数据。外部 WIQ 锚定点用于形成三个不同类别：具有“临床相关改善”、“临床相关恶化”和“无临床相关变化”的患者。根据 WIQ 锚定点，对于根据 WIQ 锚定点保持不变的 IC 患者组，通过 ACD 和 FCD 的平均变化的 95%置信区间的上限和下限来定义改善和恶化的 MID。
对于 ACD 和 FCD 的 MID 估计，分别纳入了 102 名和 101 名患者。ACD 的 MID 为改善 305 m，恶化 147 m。FCD 的 MID 为改善 250 m，恶化 120 m。
跑步机测量的 ACD 和 FCD 的 MID 可用于解释监督运动治疗后步行距离变化的临床相关性，可用于研究和个体护理。
