Kirkwood Hospice, Huddersfield, United Kingdom.
Am Heart J. 2012 Aug;164(2):229-35. doi: 10.1016/j.ahj.2012.05.003.
The aim of the study was to determine the minimally clinically important difference (MCID) for breathlessness due to chronic heart failure (CHF).
The measurement of breathlessness is difficult because it is subjective and multifactorial. Statistically significant changes in assessment may not be clinically meaningful. This is the first determination of MCID in chronic breathlessness in CHF using patient-rated data.
Measurements were made as part of a randomized, controlled, crossover trial of morphine, oxycodone, or placebo for breathlessness in CHF. Breathlessness intensity was assessed at baseline and at the end of each intervention (day 4) using 11-point numerical rating scales (NRS), modified Borg (mBorg) scales, and global impression of change (GC) in breathlessness at day 4. From these data, the change in NRS or mBorg associated with a 1-point change in GC was calculated.
Thirty-five patients completed all study interventions, resulting in 105 data sets. We defined MCID as a 1-point change in GC. Regression analysis found that the MCID, including 95% CIs, equaled change in average NRS breathlessness per 24 hours of 0.5 to 2.0 U (P < .001), change in worst NRS breathlessness per 24 hours of 0.4 to 2.9 (P < .001), change in average mBorg score of 0.2 to 2.0 (P < .001), and change in worst mBorg score as between 0.3 and 1.9 (P < .001). Corresponding effect size calculations lay within the 95% CIs for the regression analysis for each measure.
A 1-point change in NRS or mBorg score is a reasonable estimate of the MCID in average daily chronic breathlessness in CHF.
本研究旨在确定慢性心力衰竭（CHF）所致呼吸困难的最小临床重要差异（MCID）。
呼吸困难的测量较为困难，因为其具有主观性和多因素性。评估中出现统计学显著变化可能并不具有临床意义。这是首次使用患者自评数据确定 CHF 慢性呼吸困难的 MCID。
该测量是一项关于吗啡、羟考酮或安慰剂治疗 CHF 呼吸困难的随机、对照、交叉试验的一部分。使用 11 点数字评分量表（NRS）、改良 Borg 量表（mBorg）和第 4 天呼吸困难的总体印象变化（GC）在基线和每个干预结束时（第 4 天）评估呼吸困难强度。根据这些数据，计算与 GC 变化 1 分相关的 NRS 或 mBorg 变化。
35 例患者完成了所有研究干预，共产生了 105 组数据。我们将 MCID 定义为 GC 变化 1 分。回归分析发现，MCID，包括 95%CI，等于 24 小时平均 NRS 呼吸困难变化 0.5 至 2.0U（P<0.001），24 小时最差 NRS 呼吸困难变化 0.4 至 2.9（P<0.001），平均 mBorg 评分变化 0.2 至 2.0（P<0.001），最差 mBorg 评分变化 0.3 至 1.9（P<0.001）。每个测量的回归分析的效应量计算均落在 95%CI 内。
NRS 或 mBorg 评分变化 1 分是 CHF 慢性日常呼吸困难 MCID 的合理估计值。
