Evolution and prognostic factors of lupus nephritis

Background. The present study was designed to Know the clinical course of l upus nephritis and the risk factors associated with the development of end stage renal disease. Methods. This a retrospective study performed in a coh ort of 154 patients with biopsy proven lupus nephritis that were seen in ou r hospital between 1984 and 1990. The clinical records of all patients were reviewed in order to collect the following information at the time of the biopsy: age, sex, number and type of lupus criteria according with the Amer ican College of Reumathology, mean arterial pressure, serum creatinine, BUN , and albumin, as well as urinary protein excretion. The follow up was regi stered from the day the biopsy was performed to one of the following end po ints: end stage renal disease (defined as requirement of chronic dialysis), death or the end of study. All biopsies were analyzed by light microscopy to obtain the hystological subtype of lupus nephritis (WHO classification) and when type IV was diagnosed, the activity and chronicity indexes were al so assessed. Kaplan-Meier survival tables were constructed. The association of clinical and laboratory variables with the development of end stage ren al disease was obtained by log rank analysis. Variables obtained as signifi cant were used to evaluate their individual impact using either the Cox mul tivariate proportional hazard method. Results. Follow up was complete in 14 4 patients with a follow up time of 68 +/- 38 months. Ninety three patients were female with mean age of 28 +/- 9 years. At the time of the biopsy, re nal manifestations had been present for 35 +/- 38 months and the number of lupus criteria per patient were 4 +/- 1. The clinical picture at the time o f the biopsy was: nephrotic syndrome in 60 %, non nephrotic proteinuria in 40 %, and nephritic syndrome in only 2%. The hystological type of lupus nep hritis was: I in 2%, II in 8%, III in 6%, IV in 71% and V in II%. At the en d of the study 28 patients developed end stage renal disease. For the whole group the survival of renal function was 85% at 70 months and 70% at 140 m onths. All, but one patient that developed end stage renal disease exhibite d type TV nephropathy. In this subpopulation the mean activity and chronici ty indexes were 8.5 +/- 3.5 and 3.1 +/- 2.4, respectively. By multivariate analysis the strongest predictors of end stage renal disease were the serum creatinine at the time of the biopsy, chronicity index, and age. The highe r the serum creatinine and chronicity index at the time of biopsy, the high er the probability of developing end stage renal disease. Conclusions. We conclude that the clinical course of lupus nephritis in, ou r population is similar to that seen in other series. The variables indicat ing advanced renal disease, such as high serum creatinine and chronicity in dex, were the strongest predictors of end stage renal disease.