Prediction of disease progression in early rheumatoid arthritis. A study of some imaging and laboratory variables

Sammanfattning: Objective: To investigate the role of magnetic resonance imaging (MRI), assessment of bone mineral density (BMD) and antibodies to citrullinated proteins (anti-CCP) in predicting radiologic outcome in patients with early rheumatoid arthritis (RA). Patients: All patients were included in the BARFOT programme (baseline). The patients had rheumatoid arthritis of recent onset with mean disease duration of about six months. The mean age at inclusion was 55 years and two thirds were women. Methods: MRI and conventional radiography (CR) of the knee joint and forefoot were performed in 30 patients at baseline, and after 1 and 3 years. The MRI examination included evaluation of inflammation using a synovitis score and of destruction with an erosion score. BMD was measured by DEXA in 204 patients at baseline, in lumbar spine and the hip. At the same time and after 2 years radiographs of the hands and forefoot were obtained and evaluated according to the Larsen method. Anti- CCP was assessed at baseline in 379 patients. Radiographs of hands and feet were obtained at baseline and after 2 years and evaluation according to the Larsen method with respect to joint damage and progression was performed. Major findings: Baseline MRI- synovitis of the knee and of the 5th MTP joint tended to persist over time even when clinical synovitis had disappeared. MRI of the knee but not of the forefoot was superior to CR as regards the ability to detect erosions. Baseline MRI- synovitis of the knee correlated significantly with the number of MRI- erosions after one and three years and proved to be a predictor of erosivness. Also baseline MRI-synovitis of the 5th MTP joint tended to be associated with future development of erosions. DEXA measurements showed that reduced bone mass (RBM) was frequent already within one year of first symptom or sign of RA. T- and Z-scores correlated with Larsen scores at baseline and after 2 years in the total patient cohort but when calculated separately, significant correlations were found only in women. Furthermore, women but not men with RBM and osteoporosis had higher Larsen scores at baseline and after 2 years than those without. In a stepwise multiple regression analysis of women, Z-score trochanter and baseline CRP were selected as independent predictors of joint damage. Presence of anti-CCP was associated with higher Larsen score both at baseline and after 2 years. Univariate predictor analysis revealed that, after Larsen score, anti-CCP had the highest significant odds ratio for radiologic damage and progression. In stepwise multiple regression analyses, baseline Larsen score, anti-CCP and ESR were selected as independent predictors for radiological outcome. Conclusion: The results presented in the present thesis suggest that, even if prediction of disease outcome in early RA is still at a distance from perfection, the use of MRI, measurement of BMD and assessment of anti-CCP in clinical practice may contribute to improve the ability of the treating rheumatologist to make the best possible treatment decisions.