Department of Biostatistical Sciences, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
Clin Trials. 2013;10(3):463-72. doi: 10.1177/1740774513477931. Epub 2013 Mar 12.
After clinical trials end, continued follow-up of the assembled cohort often is desirable for additional research. Factors influencing participants' decisions to consent to additional follow-up and how these shape posttrial cohorts have not been broadly studied.
We examined how two re-enrollment campaigns and the passage of time altered features of the posttrial cohorts compared with the original Women's Health Initiative (WHI) Hormone Therapy clinical trials.
We examined associations that markers of sociodemography, health, lifestyle, and on-trial experiences had with re-enrollment and contrasted the characteristics of successive posttrial cohorts with those of the original enrollees.
The posttrial enrollment campaigns re-enrolled 81.1% and 82.5% of available women, respectively. Women who re-enrolled tended to have better health characteristics than those not re-enrolled. Compared to women of comparable age in the original cohort, women retained for the second posttrial follow-up less often had a history of cardiovascular disease (odds ratio (OR) = 0.36), hypertension (OR = 0.57), diabetes (OR = 0.59), or measured cognitive deficit (OR = 0.40). These women more often had graduated from high school (OR = 1.72) and had participated in other WHI trials (OR = 1.76).
We have examined experience with creating follow-up cohorts from participants in a single study. Thus, our findings may not apply to other cohorts and protocols.
Posttrial enrollment in follow-up studies can be successful; however, the characteristics of the resulting cohort may differ substantially from the originally assembled group of trial participants. Collection during the original trial of potential predictors of differential re-enrollment may strengthen interpretation of findings.
临床试验结束后，为了进行额外的研究，通常需要对已招募的队列进行持续随访。影响参与者同意额外随访的决定的因素以及这些因素如何塑造临床试验后的队列尚未得到广泛研究。
我们研究了两次重新招募活动以及随着时间的推移如何改变与原始妇女健康倡议（WHI）激素治疗临床试验相比，临床试验后的队列的特征。
我们检查了社会人口统计学、健康、生活方式和试验经历的标志物与重新入组的关联，并对比了连续的临床试验后队列的特征与原始入组者的特征。
试验后的招募活动分别重新招募了 81.1%和 82.5%的可用女性。重新入组的女性往往比未重新入组的女性具有更好的健康特征。与原始队列中年龄相仿的女性相比，第二次临床试验后随访中保留下来的女性患心血管疾病的历史较少（比值比（OR）=0.36）、高血压（OR=0.57）、糖尿病（OR=0.59）或认知缺陷（OR=0.40）。这些女性更经常从高中毕业（OR=1.72）并参加了其他 WHI 试验（OR=1.76）。
我们研究了从单个研究的参与者中创建后续队列的经验。因此，我们的发现可能不适用于其他队列和方案。
在后续研究中重新招募试验参与者可能会成功；然而，由此产生的队列的特征可能与最初招募的试验参与者群体有很大的不同。在原始试验中收集潜在的差异重新入组预测因素可能会加强对研究结果的解释。
