The clinical and renal biopsy predictors of long-term outcome in lupus nephritis: a study of 87 patients and review of the literature

Abstract

The prognostic markers in 87 consecutive patients with lupus nephritis who underwent renal biopsy are reported for five clinically relevant long-term outcomes--renal insufficiency, renal failure, death due to renal systemic lupus erythematosus, death due to non-renal SLE and death due to SLE, both renal and non-renal. We have demonstrated that a number of previously neglected or rarely studied predictors were important prognostic markers. These included the duration of renal disease before biopsy, overall severity of SLE, as well as the presence of vasculitis, hypertension or a comorbid ailment. Furthermore, the study confirms the predictive importance of serum creatinine, 24-h urinary excretion of protein, C3, and of the activity and chronicity indices on biopsy. However, overall a simple measure of tubulointerstitial disease was the best predictor obtained from biopsy. Prognostic models based on clinical data alone were developed for each of the five outcomes. The models amplify our clinical understanding of lupus nephritis. Markers of renal severity were most important in predicting renal outcomes such as renal insufficiency and renal failure. Prognostic factors less directly related to renal disease (comorbidity and vasculitis) were important predictors of fatality. A marker of immunologic disease activity (C3) was a valuable predictor for many of the outcomes. Thus markers of disease severity reflecting organ damage due to SLE and other comorbid conditions could be combined with markers of immunologic activity to predict a variety of outcomes of relevance to a clinician. When biopsy data obtained by light or electron microscopy were evaluated for their ability to add new predictive information to the clinical models, only a limited value for biopsy was noted. It is likely that this reflected the close correlational relationships between clinical and biopsy variables, the strong clinical models generated, and the inclusion in the clinical models of the previously neglected clinical variables, duration of renal disease before biopsy and the presence of vasculitis or comorbid disease.