Kurzfassung

Objective Accurate assessment of physical activity supports a comprehensive understanding and treatment of obesity and eating disorders. Here, we assessed the concurrent validity of a questionnaire and accelerometry-based measurements in a clinical setting.Methods From 2020 to 2022 a total of 23 patients from a psychosomatic clinic participated (21 with unspecified eating disorders, 2 with bulimia nervosa). During the 3rd to 4th week of the clinical stay patients completed the International Physical Activity Questionnaire-Short Form and wore an accelerometer-based multisensory device (SenseWear (R) Armband, SWA) for 7 days. Outcome measures included total physical activity (MET min.w(-1)) and sitting time (min.d(-1)). Concurrent validity (SWA as criterion) and proportional bias were assessed using regression analyses.Results The questionnaire overestimated physical activity by similar to 40% (+394 MET min.week(-1)) and underestimated sitting time by similar to 30% (199 min.day(-1)) compared to the SWA. Within-patient correlation for physical activity was good (r = 0.88, p < 0.001) but impractical for sitting time (r = 0.41, p = 0.005). Greater inactivity led to greater reporting errors in sitting time (p = 0.005). Males underestimated sitting time more than females (p = 0.026). Converting objective to subjective measures resulted in typical errors of 238 MET min (total physical activity) and 88 min (sitting time).Conclusion Objective accelerometer-based multisensory device monitoring should be incorporated into clinical settings to treat patients with obesity and eating disorders.