Wanner Miriam, Martin-Diener Eva, Bauer Georg, Braun-Fahrländer Charlotte, Martin Brian W
Swiss Federal Institute of Sport Magglingen, Magglingen, Switzerland.
J Med Internet Res. 2010 Feb 10;12(1):e3. doi: 10.2196/jmir.1361.
Web-based interventions are popular for promoting healthy lifestyles such as physical activity. However, little is known about user characteristics, adherence, attrition, and predictors of repeated participation on open access physical activity websites.
The focus of this study was Active-online, a Web-based individually tailored physical activity intervention. The aims were (1) to assess and compare user characteristics and adherence to the website (a) in the open access context over time from 2003 to 2009, and (b) between trial participants and open access users; and (2) to analyze attrition and predictors of repeated use among participants in a randomized controlled trial compared with registered open access users.
Data routinely recorded in the Active-online user database were used. Adherence was defined as: the number of pages viewed, the proportion of visits during which a tailored module was begun, the proportion of visits during which tailored feedback was received, and the time spent in the tailored modules. Adherence was analyzed according to six one-year periods (2003-2009) and according to the context (trial or open access) based on first visits and longest visits. Attrition and predictors of repeated participation were compared between trial participants and open access users.
The number of recorded visits per year on Active-online decreased from 42,626 in 2003-2004 to 8343 in 2008-2009 (each of six one-year time periods ran from April 23 to April 22 of the following year). The mean age of users was between 38.4 and 43.1 years in all time periods and both contexts. The proportion of women increased from 49.5% in 2003-2004 to 61.3% in 2008-2009 (P< .001). There were differences but no consistent time trends in adherence to Active-online. The mean age of trial participants was 43.1 years, and 74.9% were women. Comparing contexts, adherence was highest for registered open access users. For open access users, adherence was similar during the first and the longest visits; for trial participants, adherence was lower during the first visits and higher during the longest visits. Of registered open access users and trial participants, 25.8% and 67.3% respectively visited Active-online repeatedly (P< .001). Predictors of repeated use were male sex (odds ratio [OR] = 1.2, 95% confidence interval [CI] = 1.04-1.38) and increasing age category in registered open access users, and age 46-60 versus < 30 years (OR = 3.04, 95% CI = 1.25-7.38) and Swiss nationality (OR(nonSwiss)= 0.64, 95% CI = 0.41-1.00) in trial participants. Despite reminder emails, attrition was much higher in registered open access users compared with trial participants, with a median lifetime website usage of 0 days in open access users and 290 days in trial participants.
Adherence, patterns of use, attrition, and repeated participation differed between trial participants and open access users. Reminder emails to encourage repeated participation were effective for trial participants but not for registered open access users. These issues are important when interpreting results of randomized controlled effectiveness trials.
基于网络的干预措施在促进诸如体育活动等健康生活方式方面很受欢迎。然而，对于开放获取的体育活动网站的用户特征、依从性、损耗率以及重复参与的预测因素，我们知之甚少。
本研究聚焦于Active-online，这是一项基于网络的个性化体育活动干预措施。其目标包括：（1）评估并比较（a）2003年至2009年期间开放获取环境下用户特征及对该网站的依从性，以及（b）试验参与者与开放获取用户之间的用户特征及对该网站的依从性；（2）分析随机对照试验参与者与注册开放获取用户中重复使用的损耗率及预测因素。
使用Active-online用户数据库中常规记录的数据。依从性定义为：浏览的页面数量、开始定制模块的访问比例、收到定制反馈的访问比例以及在定制模块中花费的时间。依从性根据六个一年期（2003 - 2009年）以及基于首次访问和最长访问的环境（试验或开放获取）进行分析。比较试验参与者与开放获取用户之间的损耗率及重复参与的预测因素。
Active-online每年记录的访问量从2003 - 2004年的42,626次降至2008 - 2009年的8343次（六个一年期均从4月23日至次年4月22日）。在所有时间段及两种环境下，用户的平均年龄在38.4岁至43.1岁之间。女性比例从2003 - 2004年的49.5%增至2008 - 2009年的61.3%（P <.001）。对Active-online的依从性存在差异，但无一致的时间趋势。试验参与者的平均年龄为43.1岁，74.9%为女性。比较不同环境，注册开放获取用户的依从性最高。对于开放获取用户，首次访问和最长访问期间的依从性相似；对于试验参与者，首次访问时依从性较低，最长访问时依从性较高。在注册开放获取用户和试验参与者中，分别有25.8%和67.3%的人重复访问Active-online（P <.001）。重复使用的预测因素在注册开放获取用户中为男性（优势比[OR] = 1.2，95%置信区间[CI] = 1.04 - 1.38）以及年龄增长，在试验参与者中为年龄46 - 60岁相较于< 30岁（OR = 3.04，95% CI = 1.25 - 7.38）和瑞士国籍（OR（非瑞士）= 0.64，95% CI = 0.41 - 1.00）。尽管发送了提醒邮件，但注册开放获取用户的损耗率远高于试验参与者：开放获取用户网站使用的终身中位数为0天，试验参与者为290天。
试验参与者与开放获取用户在依从性、使用模式、损耗率及重复参与方面存在差异。鼓励重复参与的提醒邮件对试验参与者有效，但对注册开放获取用户无效。在解释随机对照有效性试验结果时，这些问题很重要。
