Fairhurst Caroline, Parkinson Gillian, Hewitt Catherine, Maturana Camila, Wiley Laura, Rose Fiona, Torgerson David, Hugill-Jones Jessica, Booth Alison, Bissell Laura, Tew Garry
York Trials Unit, Department of Health Sciences, University of York, York, YO10 5DD, UK.
British Wheel of Yoga Qualifications, Sleaford, NG34 7RU, UK.
NIHR Open Res. 2023 Apr 20;2:53. doi: 10.3310/nihropenres.13324.2. eCollection 2022.
Poor response rates to follow-up questionnaires can adversely affect the progress of a randomised controlled trial and the validity of its results. This embedded 'study within a trial' aimed to investigate the impact of including a pen with the postal 3-month questionnaire completed by the trial participants on the response rates to this questionnaire.
This study was a two-armed randomised controlled trial nested in the Gentle Years Yoga (GYY) trial. Participants in the intervention group of the GYY trial were allocated 1:1 using simple randomisation to either receive a pen (intervention) or no pen with their 3-month questionnaire (control). The primary outcome was the proportion of participants sent a 3-month questionnaire who returned it. Secondary outcomes were time taken to return the questionnaire, proportion of participants sent a reminder to return the questionnaire, and completeness of the questionnaire. Binary outcomes were analysed using logistic regression, time to return by Cox Proportional Hazards regression and number of items completed by linear regression.
There were 111 participants randomised to the pen group and 118 to the no pen group who were sent a 3-month questionnaire. There was no evidence of a difference in return rates between the two groups (pen 107 (96.4%), no pen 117 (99.2%); OR 0.23, 95% CI 0.02 to 2.19, p=0.20). Furthermore, there was no evidence of a difference between the two groups in terms of time to return the questionnaire (HR 0.90, 95% CI 0.69 to 1.18, p=0.47), the proportion of participants sent a reminder (OR 0.85, 95% CI 0.48 to 1.53, p=0.60) nor the number of items completed (mean difference 0.51, 95% CI -0.04 to 1.06, p=0.07).
The inclusion of a pen with the postal 3-month follow-up questionnaire did not have a statistically significant effect on response rate.
随访问卷的低回复率会对随机对照试验的进程及其结果的有效性产生不利影响。这项嵌入在试验中的“试验中的研究”旨在调查在试验参与者填写的3个月邮寄问卷中附带一支笔对该问卷回复率的影响。
本研究是一项嵌套在“温和岁月瑜伽（GYY）试验”中的双臂随机对照试验。GYY试验干预组的参与者通过简单随机化以1:1的比例分配，要么在收到3个月问卷时获得一支笔（干预组），要么不获得笔（对照组）。主要结局是收到3个月问卷并返回问卷的参与者比例。次要结局包括返回问卷所需时间、收到提醒后返回问卷的参与者比例以及问卷的完整性。二元结局采用逻辑回归分析，返回时间采用Cox比例风险回归分析，完成项目数采用线性回归分析。
随机分配到笔组的111名参与者和未分配笔组的118名参与者收到了3个月问卷。两组之间的回复率没有差异的证据（笔组107例（96.4%），无笔组117例（99.2%）；比值比0.23，95%置信区间0.02至2.19，p = 0.20）。此外，两组在返回问卷的时间（风险比为0.90，95%置信区间0.69至1.18，p = 0.47）、收到提醒的参与者比例（比值比0.85，95%置信区间0.48至1.53，p = 0.60）或完成的项目数（平均差异0.51，95%置信区间 -0.04至1.06，p = 0.07）方面均无差异的证据。
在3个月邮寄随访问卷中附带一支笔对回复率没有统计学上的显著影响。
