Self-management is crucial for individuals with chronic illnesses. While mobile applications (mAPPs) have emerged to support diverse health needs, evidence regarding their efficacy for self-management among chronically ill Filipino patients is inconsistent and limited, particularly in provincial settings.

To investigate the effectiveness of the Health Storylines mAPP compared to a traditional pamphlet for enhancing self-management among individuals with chronic illnesses in Baguio City, Philippines.

We conducted a two-arm quasi-experimental study with 33 participants diagnosed with cancer, type 2 diabetes, or heart disease/hypertension. Participants were recruited via convenience sampling and allocated to an intervention group (n=17), which used the Health Storylines mAPP for four weeks, or a comparison group (n=16), which received a traditional pamphlet. Selfmanagement was assessed pre- and post-intervention using the Self-Management Assessment Scale (SMASc).

Participants demonstrated a high level of selfmanagement at baseline (μ=5.20, SD=0.70). After four weeks, the intervention group showed a non-significant decrease in self-management scores (from μ=5.25 to 5.00, p=0.27), while the comparison group exhibited a non-significant increase (from μ=5.19 to 5.37, p=0.61). There was no statistically significant difference in posttest self-management scores between the two groups (U=83.50, p=0.23).

In a population of chronically ill patients already proficient in managing their condition, the Health Storylines mAPP had a marginal impact on selfmanagement, while the use of a traditional pamphlet showed a slight positive effect. The findings suggest that for this population, familiar, low-barrier resources remain valuable, and mHealth interventions must account for baseline self-management capabilities and digital literacy. Chronic Illness; Health Storylines mAPP; Self-management; mHealth; Philippines.