Draaijer Melvin, Lalla-Edward Samanta Tresha, Venter Willem Daniel Francois, Vos Alinda
Department of Global Health, VU Medical Center, Amsterdam University Medical Centers, Amsterdam, Netherlands.
Ezintsha (subdivision of Wits Reproductive Health and HIV Institute), University of Witwatersrand, Johannesburg, South Africa.
JMIR Form Res. 2020 Sep 30;4(9):e19138. doi: 10.2196/19138.
Long-term retention of research participants in studies is challenging. In research in sub-Saharan Africa, phone calls are the most frequently used method to distantly engage with participants.
We aimed to get insight into the effectiveness of phone calls to retain contact with participants and evaluated determinants of reachability.
A cross-sectional study was performed using the databases of two randomized controlled trials investigating different kinds of antiretroviral therapy in HIV-positive patients. One trial finished in 2018 (study 1), and the other finished in 2015 (study 2). A random sample size of 200 participants per study was obtained. There were up to 3 phone numbers available per participant collected during the studies. Participants received a maximum of 3 phone calls on every available number on different days and at different times. Voicemails were left, and emails sent wherever possible. We documented how many calls were answered, who answered, as well as after how many attempts participants were reached. To further increase our understanding of reachability, we conducted a short questionnaire assessing factors contributing to reachability. The study was approved by the Research Ethics Committee of the University of Witwatersrand, Johannesburg, South Africa (reference number M1811107).
In our sample size of n=200 per study, study 1, with a median time of 11 months since the last visit at the research site, had a response rate of 70.5% (141/200) participants while study 2, with a median duration of 55 months since the last visit, had a response rate of 50.0% (100/200; P<.001). In study 1, 61.5% (123/200) of calls were answered directly by the participant while this was 36.0% (72/200) in study 2 (P=.003). The likelihood of reaching a participant decreased with time (odds ratio [OR] 0.73, 95% CI 0.63 to 0.84) for every year since the last face-to-face visit. Having more phone numbers per participant increased reachability (OR 2.32, 95% CI 1.24 to 4.36 for 2 phone numbers and OR 3.03, 95% CI 1.48 to 6.22 for 3 phone numbers compared with 1 number). A total of 141 of 241 reached participants responded to the questionnaire. Of the 93 participants who had changed phone numbers, 5% (50/93) had changed numbers because their phone was stolen. The most preferred method of being contacted was direct calling (128/141) with participants naming this method followed by WhatsApp (69/141).
Time since last visit and the number of phone numbers listed were the only determinants of reachability. Longer follow-up time is accompanied with a decrease in reachability by phone while more listed phone numbers increases the likelihood that someone can be reached.
ClinicalTrials.gov NCT02671383; https://clinicaltrials.gov/ct2/show/NCT02671383 and ClinicalTrials.gov NCT02670772; https://clinicaltrials.gov/ct2/show/NCT02670772.
在研究中让参与者长期留存具有挑战性。在撒哈拉以南非洲地区的研究中，电话是与参与者进行远程联系最常用的方法。
我们旨在深入了解通过电话与参与者保持联系的有效性，并评估可联系性的决定因素。
使用两项随机对照试验的数据库进行了一项横断面研究，这两项试验调查了HIV阳性患者的不同抗逆转录病毒疗法。一项试验于2018年结束（研究1），另一项于2015年结束（研究2）。每项研究随机抽取200名参与者作为样本。在研究期间，每位参与者最多收集到3个电话号码。在不同日期和不同时间，每个可用号码上的参与者最多会接到3个电话。留下了语音邮件，并尽可能发送了电子邮件。我们记录了接听的电话数量、接听者以及经过多少次尝试联系到了参与者。为了进一步加深我们对可联系性的理解，我们进行了一份简短问卷，评估影响可联系性的因素。该研究获得了南非约翰内斯堡威特沃特斯兰德大学研究伦理委员会的批准（参考编号M1811107）。
在每项研究样本量为200人的情况下，研究1自上次在研究地点就诊后的中位时间为11个月，参与者的回复率为70.5%（141/200）；而研究2自上次就诊后的中位时间为55个月，回复率为50.0%（100/200；P<.001）。在研究1中，61.5%（123/200）的电话由参与者直接接听，而在研究2中这一比例为36.0%（72/200）（P=.003）。自上次面对面就诊以来，每年联系到参与者的可能性都会降低（优势比[OR]为0.73，95%置信区间为0.63至0.84）。每位参与者拥有更多电话号码会增加可联系性（与1个电话号码相比，2个电话号码的OR为2.32，95%置信区间为1.24至4.36；3个电话号码的OR为3.03，95%置信区间为1.48至6.22）。在联系到的241名参与者中，共有141人回复了问卷。在93名更换了电话号码的参与者中，5%（50/93）是因为手机被盗而更换号码。最受欢迎的联系方法是直接打电话（128/141），参与者提到这种方法之后是WhatsApp（69/141）。
自上次就诊后的时间和列出电话号码的数量是可联系性的唯一决定因素。随访时间越长，通过电话联系上的可能性越低，而列出的电话号码越多，联系到某人的可能性就越大。
ClinicalTrials.gov NCT02671383；https://clinicaltrials.gov/ct2/show/NCT02671383和ClinicalTrials.gov NCT02670772；https://clinicaltrials.gov/ct2/show/NCT02670772。
