The prognosis of rheumatoid arthritis: assessment of disease activity and disease severity in the clinic.

The prognosis of rheumatoid arthritis is best described separately for mortality, work disability, costs, functional disability, total joint arthroplasty, radiographic abnormality, and psychosocial factors. The most important determinants of prognoses are the severity and persistence of disease activity. Methods for disease activity assessment have been developed for use in clinical trials, but these are often not suitable for use in clinical practice because of time constraints, costs, and special training required. However, clinicians can measure disease activity relatively simply according to joint counts, acute-phase reactants, and patient self-report tests. Nomograms, based on percentile ranking of disease activity variables, are simple tools that can be used in the clinic to estimate disease activity and change in clinical status.