Background: The comprehensive ICF Core Set for rheumatoid arthritis (RA) is a selection of 96 categories from the International Classification of Functioning, Disability and Health (ICF), representing relevant aspects in the functioning of RA patients.
Objectives: To study the responsiveness of the ICF Core Set for RA in rheumatologic practice.
Methods: 46 RA patients (72 % females, mean (SD) age 53.6 (12.6) years, disease duration 6.3 (8.0) years) were interviewed at baseline and again after six months treatment with a DMARD, applying the ICF Core Set for RA with qualifiers for problems on a modified 3-point scale (no problem, mild/moderate, severe/complete). Patient reported outcomes included MHAQ and SF-36, and disease activity was calculated. Responsiveness was measured as change in qualifiers in ICF categories, and was also compared with change in patient reported outcomes.
Results: After 6-months DMARD treatment improvement by at least one qualifier was seen in 20% of patients averaged through all ICF categories, 71% experienced no change, and 9% worsening. Findings were similar across the different aspects of functioning. Mainly moderate effect sizes were seen for 6-month changes in the ICF Core Set for RA, especially in patients with improved health status, with similar effect size for disease activity. The components in the ICF Core Set for RA were only weakly associated with patient reported outcomes and disease activity.
Conclusions: The ICF Core Set for RA demonstrated moderate responsiveness in this real-life setting of patients where minor changes occurred during treatment with DMARDs.