Prognostic factors in rheumatoid arthritis.

To determine prognostic factors that predict the course of rheumatoid arthritis (RA) from an early phase of the disease, we reviewed publications on possible prognostic factors. We excluded studies with patients with long standing disease, studies with a followup less than one year, studies providing insufficient methodological information, and studies using noninformative outcome measures. We identified individual factors associated with worse outcome: presence of serum rheumatoid factor (RF), HLA-DR4, signs of high disease activity [number of swollen or tender joints, elevated C-reactive protein (CRP)], rheumatoid nodules, radiological abnormalities, poor grip strength, and poor functional status. The accuracy of prediction of these individual factors is low. Therefore, in several studies, combinations of entry variables were investigated for accuracy in predicting the severity of radiological abnormalities. IgM RF in combination with radiographic damage at onset of RA and either clinical measures of disease activity and/or laboratory measures such as erythrocyte sedimentation rate (ESR) or CRP and/or a functional ability score, and/or HLA-DR4 could predict radiological abnormalities with an accuracy of 70-80%. Further research should be directed to find more specific disease markers and to validate an internationally accepted combination of prognostic criteria.