Predictors of disease activity severity and outcome have both been reviewed. Although data to date have usually examined one predictor at a time, it is likely that a combination of genetic factors (HLA-DR4 or its subsets), joint tenderness or swelling, RF positivity, presence of erosions early in disease, and gender can be combined to predict disease activity/severity. The precise "mix" and contribution of these factors, however, still needs to be determined. Longer-term functional outcome can best be predicted by accounting for baseline functional disability (which reflects disease activity/severity), disease severity per se, and psychologic variables (such as depression). Again, the precise variables of most importance still need some research. Finally, mortality appears to be predicted by functional factors (thus also by disease severity), but medications (e.g., prednisone), social factors, and age (not surprisingly) also contribute to mortality.