One of the big contributors to physical inactivity in the elderly population is osteoarthritis (OA) of the knee. Digital motivation seems to have a positive effect on individual physical inactivity level, but limited evidence exists on the effects of digital motivation on patients with knee OA. To investigate if motivational text messages reduce time spent physically inactive in patients with knee OA. This study was designed as an unblinded pilot randomised controlled trial, randomising participants equally (1:1) to an intervention group (motivational text messages) or control group (no intervention). Participants were recruited from six physical therapy clinics in Denmark. Inclusion criteria were age ≥ 18, diagnosed with knee OA, owner of a smartphone or tablet, and participating or commencing participation in the GLA:D® program. The primary outcome was time spent physically inactive, measured with a tri-axial accelerometer mounted on the lateral side of the thigh. Data on OA symptoms were obtained using the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire. A total of 49 participants were screened, and 38 participants were included and randomised to either the intervention group (n = 19) or the control group (n = 19). No statistically significant difference between the two groups was found in average change of time spent physically inactive (mean difference 13.2 min/day [95% CI − 41.0 to 67.3]; P = 0.63), time spent standing (mean difference 3.0 min/day [95% CI − 22.7 to 28.7]; P = 0.81), or time spent moving (mean difference − 20.4 min/day [95% CI − 63.0 to 22.3]; P = 0.34) nor was there any difference in change between the two groups on KOOS. Motivational text messages have seemed to have no effect on overall time spent physically inactive. clinicaltrials.gov, NCT03339011 . Registered 9 November 2017

中文翻译：

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短信对减少膝关节骨性关节炎患者不活动行为的有效性：一项初步随机对照研究

导致老年人缺乏体力活动的主要原因之一是膝关节骨关节炎 (OA)。数字动机似乎对个人身体不活动水平有积极影响，但关于数字动机对膝关节 OA 患者的影响的证据有限。调查激励性短信是否可以减少膝关节 OA 患者身体不活动的时间。这项研究被设计为一项非盲试验随机对照试验，将参与者平等地（1:1）随机分配到干预组（励志短信）或对照组（无干预）。参与者是从丹麦的六家物理治疗诊所招募的。纳入标准为年龄≥ 18 岁、被诊断患有膝关节炎、拥有智能手机或平板电脑以及参与或开始参与 GLA:D® 计划。主要结果是身体不活动的时间，用安装在大腿外侧的三轴加速度计测量。使用膝关节损伤和骨关节炎结果评分 (KOOS) 问卷获得关于 OA 症状的数据。总共筛选了 49 名参与者，其中 38 名参与者被随机分配到干预组 (n = 19) 或对照组 (n = 19)。两组之间在不运动时间的平均变化（平均差异 13.2 分钟/天 [95% CI - 41.0 至 67.3]；P = 0.63）、站立时间（平均差异 3.0 分钟/天[95% CI - 22.7 至 28.7]；P = 0.81）或移动时间（平均差 - 20.4 分钟/天 [95% CI - 63.0 至 22.3]；P = 0.34）之间的变化也没有任何差异两个小组在 KOOS。励志短信似乎对身体不活动的总时间没有影响。临床试验.gov，NCT03339011。2017 年 11 月 9 日注册