Fielding Shona, Maclennan Graeme, Cook Jonathan A, Ramsay Craig R
Section of Population Health, Division of Applied Health Sciences, University of Aberdeen, Polwarth Building, Foresterhill, Aberdeen, AB25 2ZD, UK.
Trials. 2008 Aug 11;9:51. doi: 10.1186/1745-6215-9-51.
Randomised controlled trials (RCTs) are perceived as the gold-standard method for evaluating healthcare interventions, and increasingly include quality of life (QoL) measures. The observed results are susceptible to bias if a substantial proportion of outcome data are missing. The review aimed to determine whether imputation was used to deal with missing QoL outcomes.
A random selection of 285 RCTs published during 2005/6 in the British Medical Journal, Lancet, New England Journal of Medicine and Journal of American Medical Association were identified.
QoL outcomes were reported in 61 (21%) trials. Six (10%) reported having no missing data, 20 (33%) reported </= 10% missing, eleven (18%) 11%-20% missing, and eleven (18%) reported >20% missing. Missingness was unclear in 13 (21%). Missing data were imputed in 19 (31%) of the 61 trials. Imputation was part of the primary analysis in 13 trials, but a sensitivity analysis in six. Last value carried forward was used in 12 trials and multiple imputation in two. Following imputation, the most common analysis method was analysis of covariance (10 trials).
The majority of studies did not impute missing data and carried out a complete-case analysis. For those studies that did impute missing data, researchers tended to prefer simpler methods of imputation, despite more sophisticated methods being available.
随机对照试验（RCTs）被视为评估医疗保健干预措施的金标准方法，并且越来越多地纳入生活质量（QoL）测量。如果相当一部分结果数据缺失，观察到的结果容易产生偏差。本综述旨在确定是否使用插补法来处理缺失的生活质量结果。
随机选取了2005/6年期间发表在《英国医学杂志》《柳叶刀》《新英格兰医学杂志》和《美国医学会杂志》上的285项随机对照试验。
61项（21%）试验报告了生活质量结果。6项（10%）报告无缺失数据，20项（33%）报告缺失数据≤10%，11项（18%）报告缺失数据为11%-20%，11项（18%）报告缺失数据>20%。13项（21%）试验中缺失情况不明确。在61项试验中的19项（31%）中对缺失数据进行了插补。插补是13项试验主要分析的一部分，但在6项试验中作为敏感性分析。12项试验使用末次观察值结转，2项试验使用多重插补。插补后，最常用的分析方法是协方差分析（10项试验）。
大多数研究未对缺失数据进行插补，而是进行了完整病例分析。对于那些确实对缺失数据进行插补的研究，尽管有更复杂的方法可用，但研究人员倾向于更喜欢更简单的插补方法。
