Patient follow-up apps have emerged as a promising tool in healthcare to enhance patient engagement and outcomes. A mixed-methods approach was employed with quantitative data collected through surveys assessing patient satisfaction and qualitative insights gathered from interviews with facility staff. Patient satisfaction rates increased by an average of 15% following the introduction of follow-up apps, correlating with a 20% reduction in readmission rates (95% CI: -18% to -23%). The findings support the efficacy of patient follow-up apps in improving both patient satisfaction and clinical outcomes. Healthcare organizations should integrate patient follow-up apps into their routine care protocols, with particular emphasis on post-discharge management. Patient Satisfaction, Health Outcomes, Patient Follow-Up Apps, Nigerian Healthcare Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.