Section for Sports Traumatology M51, Bispebjerg and Frederiksberg Hospital, Copenhagen, Denmark.
The Research Unit for General Practice and Section of General Practice , Department of Public Health, University of Copenhagen, Copenhagen, Denmark.
Scand J Med Sci Sports. 2021 Jun;31(6):1239-1248. doi: 10.1111/sms.13855. Epub 2020 Nov 5.
Several terms are used to describe changes in PROM scores in relation to treatments. Whether the change is small, large, or relevant is defined in different ways, yet these change scores are used to recommend or oppose treatments. They are also used to calculate the necessary number of patients for a study. This article offers a theoretical explanation behind the terms responsiveness, minimal important difference (MID), minimal important change (MIC), minimal relevant difference (MIREDIF), and threshold of clinical importance. It also gives instructions on how these and the optimal number of patients for a study are calculated. Responses to two domains of the Knee Injury and Osteoarthritis Outcome Score (KOOS), before and 1 year after reconstruction of the anterior cruciate ligament of 164 patients, are used to illustrate the calculations. This paper presents the most common methods used to calculate and interpret MID. Results vary substantially across domains, patient location on the scale, and health conditions. The optimal number of patients depends on the minimal relevant difference (MIREDIF), the standard error of the measure (SEM), the desired statistical power for the measurement, and the responsiveness of the measurement instrument (the PROM). There is often uncertainty surrounding the calculation and interpretation of responsiveness, MID, and MIREDIF, as these concepts are complex. When MID is used to evaluate research results, authors should specify how the MID was calculated, and its relevance for the study population. These measures should only be used after thorough consideration to justify healthcare decisions.
有几个术语用于描述与治疗相关的 PROM 评分变化。变化的大小、重要性和相关性的定义方式各不相同，但这些变化分数被用于推荐或反对治疗方案。它们也用于计算研究所需的患者数量。本文提供了术语反应性、最小临床重要差异（MCID）、最小有意义变化（MIC）、最小有意义差异增量（MIREDIF）和临床重要性阈值背后的理论解释。它还提供了如何计算这些指标和研究所需最佳患者数量的说明。使用 164 例前交叉韧带重建患者的膝关节损伤和骨关节炎结果评分（KOOS）的两个领域的反应来举例说明这些计算。本文介绍了最常用的计算和解释 MCID 的方法。结果在不同的领域、患者在量表上的位置和健康状况方面有很大差异。最佳患者数量取决于最小有意义差异增量（MIREDIF）、测量的标准误差（SEM）、测量的期望统计效力以及测量仪器的反应性（PROM）。在计算和解释反应性、MCID 和 MIREDIF 时，常常存在不确定性，因为这些概念很复杂。当使用 MCID 来评估研究结果时，作者应指定 MCID 的计算方法及其对研究人群的相关性。只有在经过深思熟虑以证明医疗保健决策的合理性后，才能使用这些措施。
