OBJECTIVE: We evaluate the use of an app to remotely collect electronic patient-reported outcomes (ePROs) in patients attending routine rheumatology clinics with inflammatory arthritis (IA) over a four year period. METHODS: This is a secondary analysis of real-world data obtained from patients with IA who attended routine appointments between 2018 and 2022. Patients used an app to track their disease course by using Routine Assessment of Patient Index Data 3 (RAPID3), Health Assessment Questionnaire - Disability Index, or self-assessing tender and swollen joint counts. Elapsed days of the app use, number, and time between ePROs reports were analyzed using Poisson and Tobit regression models. Results were stratified by gender, age, diagnosis, baseline disease severity, and disability. RESULTS: At least one ePRO report was provided by 673 patients. Mean age was 53.7 ± 13.9 years; 458 (68%) were female. RAPID3 was reported by 613 (91%) patients, 531 (79%) provided more than one RAPID3, and 82 (12%) provided one RAPID3; there was no difference between groups stratified by gender, age, IA type, and baseline arthritis severity. Median engagement was 14.8 months (interquartile range 12.8-17). The proportion of enrolled patients completing a RAPID3 every month reduced from 91% at baseline to 38% at 6 months, and 24% at month 12. Older patients (60-69 years old) were more likely to be long-term users than those aged less than 50 years old (P < 0.006). Patients aged over 60 provided more reports than younger users (P < 0.0001). Gender, baseline arthritis activity, and disability level were not associated with the length or frequency of app use. CONCLUSION: This analysis offers insights into engagement and long-term sustainability of remote ePRO collection in a real-world rheumatology setting.