Clinical effectiveness of different feedback intensities in a pain management app - A multicenter randomized controlled trial with youths with chronic pain and their caregivers Introduction: Many children and adolescents suffer from high-impact chronic pain. While preliminary evidence suggests that intensive interdisciplinary pain treatment is effective, there is limited post-treatment support. Individualized support through a pain management app may help close this gap. Methods: We conducted a multicenter randomized controlled trial with N = 453 youths with chronic pain aged 8-17 and their caregivers. Participants had access to the app MyBrainCity from admission until six months following discharge. Immediately after discharge, participants had access to either (1) app usage statistics (reference group), (2) plus push notifications and suggestions, (3) plus on-demand chat communication with a psychologist, or (4) plus psychologist-initiated chat communication. Data were collected up to nine months after discharge. Outcomes included the functional disability inventory, the Revised Anxiety and Depression Scale, and numeric rating scales to assess pain intensity. Results: The primary analysis showed no significant differences in functional impairment between groups nine months post-discharge (χ2(3)=6.122, p=.106). Secondary analyses revealed that patients in Groups 3 and 4 showed significantly greater improvements in functional impairment compared to the reference group (-1.13 points, p<.001). Only patients in Group 4 demonstrated additional improvements in emotional burden (anxiety: -0.91 points, p<.001; depression: -0.72 points, p=.012). Patients in Group 2 had significantly greater reductions in both average (-0.24 points, p=.007) and maximum pain intensity (-0.33 points, p=.001) compared to the reference group. Conclusions: Pediatric pain management apps may be most effective when designed to include individualized, personal support. Patients especially benefit from clinician-delivered feedback following discharge. 1-25 1-25 S. Karger AG