Influence of disease activity and treatment on rate of joint destruction in rheumatoid arthritis

Severity of hands and feet joint destruction is the most objective marker of rheumatoid arthritis (RA) progression determining functional disability. The main aim of RA treatment is suppression of joint destruction. Objective. To study dependence of joint erosions forming speed on disease modifying anti-rhcumatic drugs (DMARD) administration and RA activity. Material and methods. Retrospective analysis of 451 cases of RA treatment was performed. Erosions were counted according to modified Sharp method. Erosions forming speed was counted as ratio of erosion number increase to a year’s time space. Averaged disease activity was calculated as arithmetic mean for all DAS28 values obtained during disease course. Considering close relationship between disease activity and DMARD administration two-factor analysis was used. DMARD administration (>3 months) and mean activity of RA were considered as factors. Results. Variance analysis (ANOVA) with covariant showed that mean RA activity is a significant factor influencing erosions forming speed (F=12,5; p=4xl0 4). Character of DMARD, fact of its administration and disease duration did not significantly influence erosions forming speed considering disease activity covariant. Regression model with inclusion disease duration factor mean disease activity and DMARD administration at the moment of assessment allowed to explain 42% of dispersion (determination coefficient). Conclusion. Activity of RA is the main factor influencing erosions forming speed. Therapy not decreasing activity of RA does not change erosions forming speed