Renal flares in 91 SLE patients with diffuse proliferative glomerulonephritis

BACKGROUND: Even when treated with current protocols, 25 to 30% of systemic lupus erythematosus (SLE) patients with diffuse proliferative glomerulonephritis (DPGN) evolve to end-stage renal disease (ESRD). The occurrence of renal flares is considered to be an important risk factor for the evolution to ESRD. The aim of this retrospective study was to evaluate the incidence and prognostic significance of renal flares in SLE patients with DPGN and to identify predictors for the occurrence of flares. METHODS: Ninety-one SLE patients were selected for study based on the following criteria: (a) evidence of renal involvement, (b) a follow-up of at least 6 months after the renal biopsy, and (c) a steady improvement in renal manifestations after the biopsy lasting for at least three months. RESULTS: Renal flares occurred in 54% of the patients after renal biopsy and appropriate treatment. A younger age at the time of renal biopsy correlated with the occurrence of renal flares. A high activity index (> or =10) and karyorrhexis on histology correlated with the occurrence of nephritic flares. Twenty-seven percent of the patients developed ESRD. The number of renal flares, nephritic flares, and "early" proteinuric flares (that is, those occurring in the first 18 months after renal biopsy) as well as serum creatinine levels, karyorrhexis, and chronicity index on renal histology were correlated with doubling serum creatinine. CONCLUSIONS: Our results suggest that (a) a distinct subgroup of SLE patients exists, made up of younger patients with extensive, active lesions on renal biopsy, who are at higher risk for renal flares, (b) renal flares represent important predictors of doubling serum creatinine.