Monitoring the Time Course of Disability through a Self-Assessment Instrument "Activity Index" (IA) in RA Patients

Abstract

Background: Rheumatoid arthritis (RA) is a heterogeneous autoimmune disease whose etiopathogenesis is largely unknown. Available treatments, though effective, are insufficient in so far as there is no cure for a major proportion of patients. In those patients the disease becomes chronic with progressive joint damage, disability, and limitation of participation. Current treatment approaches include pain-relieving drugs and anti-inflammatory medications that slow joint damage, combined with physical therapies involving a well-balanced, highly personalized sequence of rest and exercise. As pain-relief, overall activity, mobility and participation are vital indicators of disability and response to RA treatment, regular patient feedback in this respect is key to a successful monitoring of the long-term effect of therapy. To manage such feedback, we have developed an easyto-use self-assessment tool "Activity Index" (AI) for tablets and smartphones that enables regular assessments of RA improvement and/or deterioration in the patients' home environment. In this normative study we addressed the questions of (1) The AI sensitivity regarding the resolution of small between-patient differences; and (2) The external validity of the AI instrument when compared with "objective" laboratory and x-ray measures and the HAQ disability index.