BackgroundAlthough mobile health application (mHealth app) programs have effectively promoted disease self-management behaviors in the last decade, usage rates have tended to fall over time.ObjectiveWe used a case management approach led by a nurse and supported by a health-social partnership team with the aim of sustaining app usage among community-dwelling older adults and evaluated the outcome differences (i.e, self-efficacy, levels of depression, and total health service usages) between those who continued to use the app.MethodsThis was a 3-arm randomized controlled trial. A total of 221 older adults with hypertension, diabetes, or chronic pain were randomized into 3 groups: mHealth (n=71), mHealth with interactivity (mHealth+I; n=74), and the control (n=76). The mHealth application was given to the mHealth and mHealth+I groups. The mHealth+I group also received 8 proactive calls in 3 months from a nurse to encourage use of the app. The control group received no interventions. Data were collected at preintervention (T1), postintervention (T2), and at 3 months’ postintervention (T3) to ascertain the sustained effect.ResultsA total of 37.8% of mHealth+I and 18.3% of mHealth group participants continued using the mHealth app at least twice per week until the end of the sixth month. The difference in app usage across the 2 groups between T2 and T3 was significant (χ21=6.81,P=.009). Improvements in self-efficacy (β=4.30, 95% CI 0.25-8.35,P=.04) and depression levels (β=–1.98, 95% CI –3.78 to –0.19,P=.03) from T1 to T3 were observed in the mHealth group participants who continued using the app. Although self-efficacy and depression scores improved from T1 to T2 in the mHealth+I group, the mean values decreased at T3. Health service usage decreased for all groups from T1 to T2 (β=–1.38, 95% CI –1.98 to –0.78,P<.001), with a marginal increase at T3.ConclusionsThe relatively low rates of mHealth app usage at follow-up are comparable to those reported in the literature. More work is needed to merge the technology-driven and in-person aspects of mHealth.Trial RegistrationClinicalTrials.gov NCT03878212; https://clinicaltrials.gov/ct2/show/NCT03878212International Registered Report Identifier (IRRID)RR2-10.1159/000509129