# Evaluating usability, adherence and clinical benefit of a new digital heath application in rheumatoid arthritis: a pilot feasibility study

## TL;DR

A new digital health app for rheumatoid arthritis patients was tested for usability and potential benefits, showing better results in recently diagnosed users.

## Contribution

The study introduces a multidimensional digital health app for RA and identifies early-diagnosed patients as a subgroup that may benefit more from such interventions.

## Key findings

- The Fimo Health App showed high usability (SUS score of 74.4) and strong engagement with core features.
- Recently diagnosed RA patients (≤ 2 years) showed more pronounced improvements in physical quality of life and small favorable shifts in fatigue.
- Mental quality of life remained largely stable across all patients during the study period.

## Abstract

Digital health interventions hold promise for improving self-management in chronic inflammatory diseases such as rheumatoid arthritis (RA). The Fimo Health App was developed to support patients with RA using a multidimensional approach combining educational modules, symptom tracking, and mind–body exercises. This pilot feasibility study aimed to evaluate the usability, adherence, and potential clinical benefit of a prototype version of the app in patients with RA. A further objective was to explore patient subgroups that may particularly gain from the intervention. In a single-arm pilot trial, 31 patients with RA used the app over 12 weeks. Usability was assessed via the System Usability Scale (SUS). Primary clinical outcomes were patient-reported quality of life (SF-36 mental and SF-36 physical = Short-Form 36 Questionnaire), fatigue (FACIT-F), and pain (Visual Rating Scale Pain = VRS Pain), Secondary outcomes included functional impairment (HAQ = Health Assessment Questionnaire), global assessment, fear of motion (TSK = Tampa Scale of Kinesiophobia) and physical activity related-health competency (PAHCO). Subgroup analyses were conducted post hoc based on clinical characteristics. Usability was high (SUS = 74.4) and engagement with core app features strong (97% any use; 70% exercise completion). Across the full cohort (n = 31), changes in the primary outcomes were small overall. Physical quality of life (SF-36) showed a within-person median increase at 6 months (Hodges–Lehmann Δ =  + 5.3; r = 0.50), while fatigue (FACIT-F) and pain (VRS) exhibited only small, non-significant numerical improvements (Δ ≈ + 1 to + 4; r ≈ 0.1–0.2). Mental quality of life (SF-36 mental) remained largely stable. In the subgroup of recently diagnosed patients (≤ 2 years; n = 12), trends were more pronounced. Physical quality of life (SF-36 physical) improved consistently at 3 and 6 months (Δ =  + 1.3 to + 8.7; r = 0.67–0.85), accompanied by small favorable shifts in fatigue (Δ ≈ –1.5 to + 2; r ≈ 0.2–0.3). Mental quality of life again (SF-36 mental) remained stable over time. The Fimo Health App is a usable and well-accepted digital intervention for patients with RA. Early diagnosed Patients showed signals of potential benefit.. These findings support the value of targeted digital tools early in the RA disease trajectory. Trial Registration number: DRKS00035194, registration date: 01.10.2024, https://drks.de/register/de/trial/DRKS00035194/preview.

The online version contains supplementary material available at 10.1007/s00296-025-06060-6.