Prognostic value of Sharp index in the clinical and laboratory response toan iv methylprednisolone pulse in patients with rheumatoid arthritis

Background: No reliable variables to predict clinical or laboratory respons e to treatment in patients with rheumatoid arthritis were available until r ecently. Aim: To asses the potential predictive value of the Sharp's modifi ed radiographic joint damage index for the assessment of clinical and labor atory response to a methylprednisolone i.v. pulse. Patients and Methods: Tw enty-two patients suffering from rheumatoid arthritis received a single i.v . pulse of 1 g of methylprednisolone. Hand X-rays were taken at baseline an d blindly scored by two trained radiologists. Clinical and laboratory varia bles were assessed at baseline and at weekly intervals up to 30 days plus a 60 days final evaluation. Improvement was defined as a 50% amelioration in 4 variables. Results: Assessment of radiographic scores had a high correla tion between and within observers (intraclass correlation = 0.998). Sharp s core did not reach statistical significance as global predictor for the inf lammatory variable response to methylprednisolone. However, when the number of swollen joints was taken into account, patients with a low erosive scor e (Sharp less than or equal to 50) had a more prolonged clinical response, than patients with higher erosive score (Sharp less than or equal to 50) (F isher test p = 0.023). It is of clinical importance to point out that among patients with high Sharp score there were also responders who reached a hi gh level of improvement. A statistically significant correlation between th e basal PCR serum titers and the radiographic score (p < 0.02) was observed . Conclusions: The number of swollen joints and other variables that consid er joint structural changes should be considered for the assessment of rheu matoid arthritis patients.