Mobile apps have gained popularity in diabetes self-care among urban youth globally. A longitudinal study design with repeated measures was employed to assess user engagement and satisfaction using app-based interventions tailored to urban youth with type 2 diabetes. Mobile app usage among participants increased from 60% at baseline to 85% by the end of two years, with a significant improvement in self-reported glycemic control (p < 0.01). The study confirmed sustained user acceptance and positive health outcomes for diabetes self-care. Further research should explore long-term effects and potential barriers to maintaining app use over extended periods. Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.