Systemic lupus erythematosus.

Assessing patients with SLE is difficult because of the heterogeneity of the disease. The Revised 1982 ARA Classification Criteria set has been widely accepted for classifying SLE patients for inclusion in clinical studies, but it is not appropriate for making the diagnosis of SLE in an individual and is not helpful for classifying patients with early or mild disease in population based epidemiological studies. Further refinement of this criteria set to meet these objectives and to facilitate subdivision of patients with SLE into those with similar clinical, serological or genetic features poses a future challenge for the clinical epidemiologist. A number of valid and reliable indices are available for measuring clinical disease activity in SLE (Table 3). Despite their different approaches they have been shown to correlate well with each other and hence would appear to be measuring the same thing. The exact choice of instrument will be dictated by the purpose for which it is required. Although none is perfect they are useful for monitoring groups of patients in outcome studies in a research setting. Practically, disease activity indices are unlikely to be appropriate for dictating treatment decisions in individual cases: an instrument comprehensive and flexible enough for this purpose would undoubtedly be far too cumbersome for widespread use. Ultimately such fine tuning will continue to rely upon the skill and intuition of experienced physicians.