Association between Sharp's radiographic index and acute phase reactants in rheumatoid arthritis

The aim of this study was to evaluate the activity of rheumatoid arthritis (RA) by hand radiography (Sharp's radiographic index), and assessment of acute phase reactants - erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and rheumatoid factor (RF), and to determine their value as prognostic markers for disease outcome in patients with early RA treated with disease modifying antirheumatic drugs (DMARDs)-Methotrexate (MTH); to register and quantify clinical, radiographic and laboratorial differences in certain time intervals in a group of patients treated with immunomodulation therapy with MTH; to determine which of the acute phase reactants would be the most useful marker for evaluation of disease activity in long-term follow-up in RA patients; to select high-risk groups with aggressive course of disease, in order to emphasize the necessity of early and aggressive treatment. Thirty patients with early RA (disease evolution up to 1 year) were evaluated in several time intervals. The score of the Sharp's index showed greater radiographic progression of the joint damage of hands in time intervals between 0-time and 12 months (p=0.0167) and between 0-time and 18 months (p=0.0089). Statistical analysis showed differences in values of CRP in four time intervals (p=0.00002). Considering CRP, there were statistically significant differences among mean values in four time intervals (p=0.0428) (standard deviations showed greater variations). There were no statistically significant differences among mean values of RF in four time intervals (p=0.573). At 0-time in 3 (10%) patients progression of the Sharp's index was found, after 6 months in 13 (39%) patients, while after 12 and 18 months progression of the Sharp's index was found in an identical number of patients, 15 (50%). In most patients high values of CRP and RF were found. Progression of the radiographic damage is especially expressed in patients with high values of ESR, CRP, RF and existence of previous erosions of hands, which are predictors for aggressive course of disease. CRP is the most useful marker for the evaluation of RA activity in the long-term follow-up of RA patients.