Development and evaluation of the Baowan Baochai mobile application to support preventive foot care in adults with type 2 diabetes mellitus: A research and development study

Objectives Diabetic foot complications are a major source of morbidity in type 2 diabetes mellitus (T2DM), yet continuous support for preventive self-care remains limited. This study developed and preliminarily evaluated Baowan Baochai, a Health Belief Model (HBM)-based mobile application for preventive foot care. Methods A five-phase research and development design comprised a qualitative needs assessment (20 adults with T2DM, five providers), HBM-informed development, four-week pilot testing (30 patients, 10 providers), iterative refinement, and a four-week single-group evaluation (60 adults with T2DM). We analyzed interview, questionnaire, and system usage log data using paired-samples t-tests, exact McNemar and Wilcoxon signed-rank tests, and thematic analysis. Results The needs assessment identified inconsistent preventive foot-care practices, low confidence, and a need for practical digital support, which informed HBM-linked functions comprising guided foot inspection, symptom and photo logging, reminders, educational content, and a provider dashboard. In pilot testing, users adopted foot-problem logging (83.3%) and medication reminders (76.7%) more often than lifestyle tracking (46.7%), prompting refinements to navigation, reminders, content, and dashboard displays. In the final evaluation the descriptive 26-item User Experience Questionnaire (UEQ) mean rose from 0.35 ± 0.42 to 0.62 ± 0.38 and PVS mean item scores from 4.21 ± 0.47 to 4.56 ± 0.41 (both P < 0.001; Cohen’s d av = 0.68 and 0.80), and daily foot inspection rose from 43.3% to 76.7% (exact McNemar P < 0.001). Foot-problem events fell from 10 to seven, but not significantly ( P = 0.250). Conclusions Baowan Baochai was feasible over four weeks, with improvements in user experience, perceived value, and daily foot inspection. UEQ scores nevertheless remained within the neutral range, and the uncontrolled design precludes causal conclusions. Controlled studies with longer follow-up and clinically verified outcomes are required.