Jaeb Center for Health Research, Tampa, FL, USA.
Wilmer Eye Institute, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
Clin Trials. 2020 Apr;17(2):195-201. doi: 10.1177/1740774519894229. Epub 2020 Jan 27.
BACKGROUND/AIMS: In clinical trials, participant retention is critical to reduce bias and maintain statistical power for hypothesis testing. Within a multi-center clinical trial of diabetic retinopathy, we investigated whether regular phone calls to participants from the coordinating center improved long-term participant retention.
Among 305 adults in the Diabetic Retinopathy Clinical Research Retina Network Protocol S randomized trial, 152 participants were randomly assigned to receive phone calls at baseline, 6 months, and annually through 3 years (annual contact group) while 153 participants were assigned to receive a phone call at baseline only (baseline contact group). All participants could be contacted if visits were missed. The main outcomes were visit completion, excluding deaths, at 2 years (the primary outcome time point) and at 5 years (the final time point).
At baseline, 77% (117 of 152) of participants in the annual contact group and 76% (116 of 153) in the baseline contact group were successfully contacted. Among participants in the annual contact group active at each annual visit (i.e. not dropped from the study or deceased), 85% (125 of 147), 79% (108 of 136), and 88% (110 of 125) were contacted successfully by telephone around the time of the 1-, 2-, and 3-year visits, respectively. In the annual and baseline contact groups, completion rates for the 2-year primary outcome visit were 88% (129 of 147) versus 87% (125 of 144), respectively, with a risk ratio of 1.01 (95% confidence interval: 0.93-1.10, = .81). At 5 years, the final study visit, participant completion rates were 67% (96 of 144) versus 66% (88 of 133) with a risk ratio of 1.01 (95% confidence interval = 0.85-1.19, = .93). At 2 years, the completion rate of participants successfully contacted at baseline was 89% (202 of 226) versus 80% (52 of 65) among those not contacted successfully (risk ratio = 1.12, 95% confidence interval = 0.98-1.27, = .09); at 5 years, the completion percentages by baseline contact success were 69% (148 of 213) versus 56% (36 of 64; risk ratio = 1.24, 95% confidence interval = 0.98-1.56, = .08).
Regular phone calls from the coordinating center to participants during follow-up in this randomized clinical trial did not improve long-term participant retention.
背景/目的：在临床试验中，参与者的保留率对于减少偏倚和保持假设检验的统计效力至关重要。在一项关于糖尿病视网膜病变的多中心临床试验中，我们研究了协调中心定期给参与者打电话是否能提高长期参与者的保留率。
在糖尿病视网膜病变临床研究视网膜网络方案 S 的随机试验中，305 名成年人中，152 名参与者被随机分配在基线、6 个月和每年（年度联系组）接受电话随访，直至 3 年；153 名参与者仅在基线时接受电话随访（基线联系组）。如果错过就诊，可以联系所有参与者。主要结局是在 2 年（主要终点时间）和 5 年（最终时间点）时完成就诊，排除死亡。
在基线时，年度联系组 152 名参与者中有 77%（117 名），基线联系组 153 名参与者中有 76%（116 名）成功联系。在年度联系组中，每个年度就诊时保持活跃（即未从研究中退出或死亡）的 147 名参与者中，分别有 85%（125 名）、79%（108 名）和 88%（110 名）在 1 年、2 年和 3 年就诊时成功通过电话联系。在年度和基线联系组中，2 年主要结局就诊的完成率分别为 88%（129 名）与 87%（125 名），风险比为 1.01（95%置信区间：0.93-1.10， = 0.81）。在 5 年时，即最后一次研究就诊，参与者的完成率分别为 67%（96 名）与 66%（88 名），风险比为 1.01（95%置信区间：0.85-1.19， = 0.93）。在 2 年时，成功联系到的基线参与者的完成率为 89%（202 名）与未成功联系到的参与者的完成率为 80%（52 名）（风险比为 1.12，95%置信区间：0.98-1.27， = 0.09）；在 5 年时，通过基线联系成功的完成率分别为 69%（148 名）与 56%（36 名）（风险比为 1.24，95%置信区间：0.98-1.56， = 0.08）。
在这项随机临床试验中，协调中心在随访期间定期给参与者打电话并没有提高长期参与者的保留率。
