Clinical Epidemiology and Biostatistics Unit, Murdoch Children's Research Institute, Parkville, Victoria, Australia.
Quality Use of Medicines and Pharmacy Research Centre, Clinical and Health Sciences, University of South Australia, Adelaide, South Australia, Australia.
Stat Med. 2021 Sep 20;40(21):4660-4674. doi: 10.1002/sim.9088. Epub 2021 Jun 8.
Medical research often involves using multi-item scales to assess individual characteristics, disease severity, and other health-related outcomes. It is common to observe missing data in the scale scores, due to missing data in one or more items that make up that score. Multiple imputation (MI) is a popular method for handling missing data. However, it is not clear how best to use MI in the context of scale scores, particularly when they are assessed at multiple waves of data collection resulting in large numbers of items. The aim of this article is to provide practical advice on how to impute missing values in a repeatedly measured multi-item scale using MI when inference on the scale score is of interest. We evaluated the performance of five MI strategies for imputing missing data at either the item or scale level using simulated data and a case study based on four waves of the Longitudinal Study of Australian Children (LSAC). MI was implemented using both multivariate normal imputation and fully conditional specification, with two rules for calculating the scale score. A complete case analysis was also performed for comparison. Based on our results, we caution against the use of a MI strategy that does not include the scale score in the imputation model(s) when the scale score is required for analysis.
医学研究通常涉及使用多项目量表来评估个体特征、疾病严重程度和其他与健康相关的结果。由于构成该评分的一个或多个项目中存在缺失数据，因此在量表评分中观察到缺失数据是很常见的。多重插补（MI）是一种处理缺失数据的常用方法。然而，在量表评分的背景下，尚不清楚如何最好地使用 MI，特别是当它们在多次数据收集的多个波次中进行评估，导致项目数量众多时。本文的目的是提供有关如何使用 MI 在重复测量的多项目量表中插补缺失值的实用建议，当对量表评分进行推断时，这是很有意义的。我们使用模拟数据和基于澳大利亚儿童纵向研究（LSAC）的四个波次的案例研究评估了五种在项目或量表水平上插补缺失数据的 MI 策略的性能。MI 使用多元正态插补和完全条件指定来实现，其中包括两种计算量表评分的规则。还进行了完全案例分析以供比较。根据我们的结果，我们警告说，当需要对量表评分进行分析时，在插补模型中不包括量表评分的 MI 策略是不可取的。
