Rodriguez Fatima, Harrison Robert W, Wojdyla Daniel, Mahaffey Kenneth W
From the *Division of Cardiovascular Medicine, Stanford University, Stanford, CA; and †Duke Clinical Research Institute, Durham, NC.
Crit Pathw Cardiol. 2015 Dec;14(4):150-3. doi: 10.1097/HPC.0000000000000055.
High rates of lost to follow-up (LTFU) and withdrawal of consent (WDC) may introduce uncertainty around the validity of the results of clinical trials. We sought to better understand published proportions of LTFU and WDC in large contemporary cardiovascular clinical trials.
Large (>5000 randomized subjects) cardiovascular clinical trials published between 2007 and 2012 in N Engl J Med were systematically reviewed. Data regarding LTFU and WDC were extracted from the primary manuscripts and supplementary online material.
Twenty-five published randomized trials were identified. Trials ranged in size from 5518 to 26449 subjects. All trials reported LTFU with 15 separately reporting WDC. The duration of follow-up ranged from 30 days to 6.2 years. The number of subjects LTFU ranged from 8 to 905, and the median proportion of subjects LTFU was 0.23% (interquartile range: 0.12%-0.58%). Individual LTFU proportions varied 300-fold, from 0.03% to 9.7%. Proportions of WDC ranged from 0.02% to 8.3%-a 400-fold difference-with a median of 1.1% (interquartile range: 0.2%-2.6%). WDC occurred more frequently than LTFU in all but 2 studies.
Contemporary cardiovascular clinical trials typically have low proportions of LTFU or WDC, but some trials have approximately 10% of subjects with LTFU or WDC. WDC occurred more frequently than LTFU but was only reported in 60% of the trials. These results emphasize the need to standardize reporting of LTFU and WDC as important trial metrics of quality and to develop strategies to minimize their occurrence.
高失访率（LTFU）和撤因（WDC）可能会使围绕临床试验结果有效性的不确定性增加。我们试图更好地了解当代大型心血管临床试验中已发表的LTFU和WDC比例。
对2007年至2012年在《新英格兰医学杂志》上发表的大型（>5000名随机受试者）心血管临床试验进行系统回顾。从主要手稿和在线补充材料中提取有关LTFU和WDC的数据。
确定了25项已发表的随机试验。试验规模从5518名受试者到26449名受试者不等。所有试验均报告了LTFU，其中15项分别报告了WDC。随访时间从30天到6.2年不等。失访受试者数量从8名到905名不等，失访受试者的中位数比例为0.23%（四分位间距：0.12%-0.58%）。个体失访比例相差300倍，从0.03%到9.7%。撤因比例从0.02%到8.3%，相差400倍，中位数为1.1%（四分位间距：0.2%-2.6%）。除2项研究外，WDC在所有研究中比LTFU更频繁发生。
当代心血管临床试验中LTFU或WDC的比例通常较低，但有些试验约有10%的受试者出现LTFU或WDC。WDC比LTFU更频繁发生，但仅在60%的试验中报告。这些结果强调需要将LTFU和WDC的报告作为重要的试验质量指标进行标准化，并制定策略以尽量减少其发生。
