ImportanceThe Kansas City Cardiomyopathy Questionnaire (KCCQ) is a commonly used outcome in heart failure trials. While comparing means between treatment groups improves statistical power, mean treatment effects do not necessarily reflect the clinical benefit experienced by individual patients.ObjectiveTo evaluate the association between mean KCCQ treatment effects and the proportions of patients experiencing clinically important improvements across a range of clinical trials and heart failure etiologies.Design, Setting, and ParticipantsA patient-level analysis of 11 randomized clinical trials, including 9977 patients, was performed to examine the association between mean treatment effects and the KCCQ Overall Summary Score (OSS) and the absolute differences in the proportions of patients experiencing clinically important (≥5 points) and moderate to large (≥10 points) improvements. There was no target date range, and included studies were those for which patient-level data were available. Validation was performed in 7 additional trials. The data were analyzed between July 1 and September 15, 2023.Main Outcomes and MeasuresProportion of patients experiencing an improvement of 5 or more and 10 or more points in their KCCQ score (with each domain transformed to a range of 0 to 100 points, where higher scores represent better health status).ResultsGroup mean KCCQ-OSS differences were strongly correlated with absolute differences in clinically important changes (Spearman correlations 0.76-0.92). For example, a mean KCCQ-OSS treatment effect of 2.5 points (half of a minimally important difference for an individual patient) was associated with an absolute difference of 6.0% (95% prediction interval [PI], 4.0%-8.1%) in the proportion of patients improving 5 or more points and 5.0% (95% PI, 3.1%-7.0%) in the proportion improving 10 or more points, corresponding to a number needed to treat of 17 (95% PI, 12-25) and 20 (95% PI, 14-33), respectively.Conclusions and RelevanceInferences about clinical impacts based on population-level mean treatment effects may be misleading, since even small between-group differences may reflect clinically important treatment benefits for individual patients. Results of this study suggest that clinical trials should explicitly describe the distributions of KCCQ change at the patient level within treatment groups to support the clinical interpretation of their results.

中文翻译：

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解释堪萨斯城心肌病问卷中的总体平均治疗效果


重要性堪萨斯城心肌病问卷 （KCCQ） 是心力衰竭试验中常用的结果。虽然比较治疗组之间的平均值可以提高统计能力，但平均治疗效果并不一定反映个体患者所经历的临床获益。目的评估平均 KCCQ 治疗效果与在一系列临床试验和心力衰竭病因中经历临床重要改善的患者比例之间的关联。设计、设置和参与者对 11 项随机临床试验（包括 9977 名患者）进行了患者层面的分析，以检查平均治疗效果与 KCCQ 总体总分 （OSS） 之间的关联，以及经历临床重要 （≥5 分） 和中度至重度 （≥10 分） 改善的患者比例的绝对差异。没有目标日期范围，纳入的研究是那些有患者水平数据的研究。在另外 7 项试验中进行了验证。主要结果和措施 KCCQ 评分改善 5 分或以上且 10 分或以上的患者比例（每个领域转换为 0 到 100 分的范围，其中分数越高代表健康状况越好）。结果组均值 KCCQ-OSS 差异与临床重要变化的绝对差异密切相关 （Spearman 相关性 0.76-0.92）。例如，平均 KCCQ-OSS 治疗效果为 2.5 分（个体患者最小重要差异的一半）与 6.0% （95% 预测区间 [PI]，4.0%-8.1%）的绝对差异相关，患者比例提高 5 分或以上和 5 分。0% （95% PI，3.1%-7.0%） 的比例提高 10 分或更多，对应于需要治疗的人数分别为 17 （95% PI，12-25） 和 20 （95% PI，14-33）。结论和相关性基于人群水平平均治疗效果的临床影响推断可能具有误导性，因为即使是很小的组间差异也可能反映出个体患者的临床重要治疗益处。本研究的结果表明，临床试验应明确描述治疗组内患者水平 KCCQ 变化的分布，以支持对其结果的临床解释。