To determine prognostic factors of disability in early rheumatoid arthritis (RA) and to investigate the radiological and functional course of the disease.
A total of 191 patients with early RA (diagnosed for less than one year) according to American College of Rheumatology criteria were followed prospectively for 5 years. At baseline and at endpoint, Stanford Health Assessment Questionnaire (HAQ) scores and radiological scores (Sharp's score modified by van der Heijde) were performed. Correlations between numerous baseline data and HAQ score at endpoint were analyzed, using nonparametric tests. A multilinear regression model was performed to select independent prognostic factors of HAQ disability.
During the 5-year followup, mean HAQ decreased from 1.3 (+/- 0.7) to 0.6 (+/- 0.6). There were 98 (65.3%) patients with a score > 1 point at baseline, but only 46 (27.4%) after 3 years and 34 (21.8%) after 5 years. Moreover, 90% of the patients had an improvement of the disability score. Final HAQ disability was associated with baseline values of HAQ score, Pain, Ritchie index, tender joint count, Disease Activity Score, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and erosion. Multivariate analysis selected baseline HAQ score, Ritchie index, ESR, CRP, and presence of erosion as independent prognostic factors of HAQ disability. The probability cutoff in the logistic model was selected to minimize the sum of false positive and false negative values: negative predictive value = 92.71%, positive predictive value = 46.15%, p = 0.408. Sex, age, IgM and IgA rheumatoid factors, other tested autoantibodies, and HLA class II genes did not contribute significantly to prediction of the disability after 5 years. At baseline, mean scores were 3.6 units (+/- 7.7) for total radiological score, 1.7 (+/- 4.5) for erosion score, and 1.9 (+/- 3.7) for joint space narrowing score. After 5 years, they were 17.9 +/- 22.3, 6.9 +/- 9.5, and 11.0 +/- 15.4, respectively. No erosion was present at the start in 58.0% of patients, compared to 24.2% and 22.4% at 3 and 5 years. Global radiographic progression concerned 87 patients (55.8%) during the 5 years.
During the first 5 years of RA, radiological damage increased progressively in half of the patients, whereas HAQ disability improved in most of them during the same period of time and could be predicted by baseline values of HAQ score, Ritchie index, ESR, CRP, and presence (or absence) of erosion.