Background:Self-management is of paramount importance in non-surgical treatment of knee and/or hip osteoarthritis(OA). Modern technologies offer the possibility to support self-management 24/7. We developed an e-self-management application (dr. Bart app) for people with knee and/or hip OA.Objectives:To document the use of the dr. Bart app and its relation with health care utilization and clinical outcomes in people with knee and/or hip OA.Methods:For this study we used back end data of the first 26 weeks from the intervention group (N=214) of a RCT (total included 427) examining the effectiveness of the dr. Bart app. Participants were included based on self-reported knee and/or hip OA. In figure 1 the theoretical framework of the dr. Bart app is presented. A central element of the dr. Bart app is that the app proposes a selection of 72 preformulated goals for health behaviours based on the ‘tiny habits method’¹(e.g. today I rise 12 times from my chair to train my leg muscles). The proposals are tailored to user characteristics and related to four themes that are core elements in the non-surgical management of OA. After a user completes one or more of the selected goals, a new selection is proposed by dr. Bart. A user can work on 3 goals simultaneously. Goals can be completed more than once by the same user. To assess the association between intensity of use of the app and health care utilization and clinical outcomes, we calculated Spearman rank correlation coefficients.Figure 1.Theoretical framework of the dr. Bart app.Results:171 / 214 participants (80 %) logged in at least once whilst 151 (71%) chose at least one goal and 114 (53 %) completed at least one goal during the 26 weeks. Of those who chose at least one goal, 56 participants (37 %) continued to log in up to 26 weeks, 12 (8 %) continued to select new goals from the offered goals and 37 (25 %) continued to complete goals (Figure 2). Preformulated goals regarding the themes activity (e.g. performing an exercise from the exercises library of the app) and nutrition (e.g. eat 2 pieces of fruit today) were found to be most popular by users. We found no correlations between intensity of use and health care utilization and clinical outcomes.Figure 2.Percentage of active users (N=151) over time.Conclusion:A considerable proportion of persons with knee and/or hip OA persistently used the app up to 26 weeks. Patients appear to have preferences for goals related to activity and nutrition, rather than for goals related to vitality and education. We found no relation between intensity of use of the dr. Bart app and health care utilization and clinical outcomes.References:[1] Fogg GJ: A behavior model for persuasive design. In: Proceedings of the 4^thinternational Conference on Persuasive Technology: 2009: ACM; 2009: 40.Disclosure of Interests:None declared