Characterizing Adherence to a Mobile Health App for Patient-Reported Outcomes in Rheumatoid Arthritis

Adoption of mobile health applications ("apps") that collect patient-reported outcomes (PROs) into clinical practice remains limited, and studies about patient usage preferences are lacking. Our aim was to characterize adherence to a PRO app designed for patients with rheumatoid arthritis (RA).

We performed a post hoc analysis of a non-randomized trial of a PRO app for patients with RA seen at an academic medical center. The 12-month trial enrolled 149 participants with RA. The app collected one of four PROs every other day. We calculated adherence using two methods: (1) percent of PROs completed, and (2) time until app non-use. These calculations used different intervals for PRO completion and different periods of non-use to define adherence. We also investigated the association of potential predictors on the outcome using multivariable regression models.

The percentage of completed PROs was 43.5% (standard deviation, SD = 27.8) using a 2-day interval between PROs; this included all possible PRO questionnaires. Adherence was 68.0% (SD = 34.0) for any completion in an 8-day interval, and 77.3% (SD = 30.9) for a 32-day interval. In survival analyses, describing time until app non-use, the mean number of days until cessation was 153.8 days (SD = 94.1), defining non-use as ≥ 32 days without PRO completion and 152.3 days (SD = 95.8) for ≥ 64 days. We observed that older age and more frequent physician engagement with the PROs data were associated with greater adherence and increased time until cessation.

Adherence to longitudinal PRO symptom reporting through an app was moderate and varied depending on how it was measured; the 8-day interval (approximately 1 week) is likely the most realistic expectation for patient completion of PRO symptoms. Adherence correlates with patient and physician factors.