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High rates of lost to follow-up (LTFU) may introduce uncertainty around the validity of the results of clinical trials. The goal of this research is to better understand published proportions of LTFU in large contemporary cardiovascular clinical trials.
Large (>5000 randomized subjects) cardiovascular clinical trials published between 2007 and 2012 in the New England Journal of Medicine were reviewed. Data regarding LTFU and withdrawal of consent (WDC) were extracted from the primary manuscripts and supplementary on-line material.
22 published randomized trials were identified. Trials ranged in size from 5,518 to 26,449 subjects. All trials reported LTFU with 13 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 125, and the median proportion of subjects LTFU was 0.19% (IQR 0.11% – 0.57%). Individual LTFU proportions varied 30-fold, from 0.03% to 1.0% (Figure). Proportions of WDC ranged from 0.02% to 8.3% – a 400-fold difference – with a median of 1.1% (IQR 0.2%-2.0%). WDC occurred more frequently than LTFU in all but two studies.
Contemporary cardiovascular clinical trials have low proportions of LTFU but in some trials over 100 patients had LTFU. WDC occurred more frequently 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.
Poster Sessions, Expo North
Monday, March 11, 2013, 9:45 a.m.-10:30 a.m.
Session Title: Critical Appraisal of Research Methods
Abstract Category: 28. Quality of Care and Outcomes Assessment
Presentation Number: 1287-92
- 2013 American College of Cardiology Foundation