A "state model" of renal function in systemic lupus erythematosus: its value in the prediction of outcome in 292 patients.

We defined a clinical staging of renal function in systemic lupus erythematosus (SLE) which uses inexpensive outpatient measures to serially stage patient status and then analyzed the disease course of 292 patients followed since 1968. The 4 mutually exclusive states used were (1) normal (creatinine less than 1.2 mg/dl and protein less than 2+ on dipstick); (2) proteinuria alone (creatinine less than 1.2 mg/dl and protein greater than or equal to 2+ on dipstick); (3) moderate filtration dysfunction (creatinine greater than or equal to 1.2 mg/dl and less than 4.0 mg/dl); and (4) severe azotemia (creatinine greater than or equal to 4.0 mg/dl). Duration in each state and subsequent transitions were incorporated in an assessment of outcome. Prognostic variables were found which predicted different outcomes within each of the 4 states. This stratification, based on renal function over time, provides a useful analytical tool for comparing subsets of patients with lupus. We found that serum complement (C3) predicted progression in state 1 and 2 as well as potential responders to therapy in state 3. No improvement was noted for patients in state 4.