Tractenberg Rochelle E, Yumoto Futoshi, Aisen Paul S
Departments of Neurology, Biostatistics, Bioinformatics & Biomathematics, and Psychiatry, Georgetown University Medical Center, Washington, D.C., USA ; Collaborative for Research on Outcomes and-Metrics.
Collaborative for Research on Outcomes and-Metrics ; IMPAQ International, Columbia, USA.
Open J Philos. 2013 Nov 1;3(4A):24-31. doi: 10.4236/ojpp.2013.34A005.
To demonstrate challenges in the estimation of change in quality of life (QOL).
Data were taken from a completed clinical trial with negative results. Responses to 13 QOL items were obtained 12 months apart from 258 persons with Alzheimer's disease (AD) participating in a randomized, placebo-controlled clinical trial with two treatment arms. Two analyses to estimate whether "change" in QOL occurred over 12 months are described. A simple difference (later - earlier) was calculated from total scores (standard approach). A Qualified Change algorithm (novel approach) was applied to each item: differences in ratings were classified as either: improved, worsened, stayed poor, or stayed "positive" (fair, good, excellent). The strengths of evidence supporting a claim that "QOL changed", derived from the two analyses, were compared by considering plausible alternative explanations for, and interpretations of, results obtained under each approach.
Total score approach: QOL total scores decreased, on average, in the two treatment (both -1.0, < 0.05), but not the placebo (=-0.59, > 0.3) groups. Qualified change approach: Roughly 60% of all change in QOL items was worsening in every arm; 17% - 42% of all subjects experienced change in each item.
Totalling the subjective QOL item ratings collapses over items, and suggests a potentially misleading "overall" level of change (or no change, as in the placebo arm). Leaving the items as individual components of "quality" of life they were intended to capture, and qualifying the direction and amount of change in each, suggests that at least 17% of any group experienced change on every item, with 60% of all observed change being worsening.
Summarizing QOL item ratings as a total "score" collapses over the face-valid, multi-dimensional components of the construct "quality of life". Qualified Change provides robust evidence of changes to QOL or "enhancements of" life quality.
证明生活质量（QOL）变化评估中的挑战。
数据取自一项结果为阴性的已完成临床试验。从参与一项有两个治疗组的随机、安慰剂对照临床试验的258名阿尔茨海默病（AD）患者中，相隔12个月获取了对13个QOL项目的回答。描述了两种用于评估QOL在12个月内是否发生“变化”的分析方法。从总分计算简单差值（后期 - 早期）（标准方法）。将合格变化算法（新方法）应用于每个项目：评分差异被分类为以下几种情况：改善、恶化、保持较差或保持“积极”（一般、良好、优秀）。通过考虑对每种方法所得结果的合理替代解释和解读，比较了两种分析方法支持“QOL发生了变化”这一说法的证据强度。
总分法：两个治疗组的QOL总分平均下降（均为 -1.0，P < 0.05），但安慰剂组未下降（=-0.59，P > 0.3）。合格变化法：每个治疗组中，QOL项目所有变化中约60%为恶化；各项目中17% - 42%的所有受试者经历了变化。
将主观QOL项目评分相加会掩盖各个项目的情况，并暗示可能产生误导的“总体”变化水平（或无变化，如安慰剂组）。将各个项目视为旨在反映生活“质量”的单独组成部分，并对每个项目变化的方向和程度进行限定，这表明任何组中至少17%的受试者在每个项目上都经历了变化，且所有观察到的变化中有60%为恶化。
将QOL项目评分总结为一个总“分数”会掩盖“生活质量”这一构念在表面效度、多维度组成部分方面的情况。合格变化法为QOL的变化或生活质量的“提升”提供了有力证据。
