PS8:168 Proteinuria in relation to class of lupus nephritis – a retrospective single-centre study

Purpose Lupus nephritis (LN) is one of the most severe organ complications of Systemic lupus erythematosus (SLE) affecting up to 60% throughout the course of their disease. Currently, LN is classified according to the ISN/RPS classification. Classes III/IV require aggressive immunosuppressive treatment to avoid end-stage renal disease. However, there are no clinical or serological parameters to predict the type of renal disease and overall renal prognosis. Methods We performed a single-centre study at our institution of all patients who underwent a renal biopsy between 2001 and 2017. Proteinuria, creatinine and other clinical/serological data were collected. Median values were analysed with ANOVA and Bonferroni’s correction for multiple comparisons. Results 49 patients were analysed in our study. 3 patients were excluded because of incomplete data. The remaining 46 patients were stratified according to the histopathological class of Lupus nephritis. 2 patients had class I, 7 patients had class II, 12 patients had class III, 2 patients had class III/V, 15 patients had class IV, 2 patients had class IV/V and 6 patients had pure class V. Median proteinuria at or around the nearest time point to renal biopsy were 1487 mg/g creatinine (Cr) (class I), 1515 mg/g Cr (class II), 1373 mg/g Cr (class III), 3528 mg/g Cr (class III/V), 3190 mg/g Cr (class IV), 5741 mg/g Cr (class IV/V) and 1773 mg/g Cr (class V). While LN classes III/V, IV and IV/V showed the highest median proteinuria, there was no statistical difference between groups. Conclusions Although often presumed, proteinuria is not a reliable marker for the various types of Lupus nephritis. There was a higher median proteinuria with class V (pure or combined) membranous nephropathy, however, even proteinuria in this group was not significantly different compared with the other groups. Lack of reliable clinical markers challenges the current lupus nephritis classification system, a combination of clinical, serological and histopathological findings might more appropriately predict the overall prognosis in LN.