The role for renal histology as predictor for outcome in lupus nephritis in Western Australia

Objectives: Continuous demographic change with new mechanistic insights and treatment options necessitate regular updating of our knowledge on Lupus Nephritis (LN). We investigated the current role of demographic, clinical and histological characteristics as outcome predictors in LN patients in Western Australia (WA). Method: A retrospective single centre study of all adult SLE patients with a first renal biopsy compatible with LN between 1997–2017 seen at a metropolitan tertiary hospital in WA. Demographic, laboratory, renal biopsy (ISN class) and treatment data were collected at baseline. Annual incidence rates per 100.000 population used ABS 2006 census and country of origin data. Kaplan Meyer survival estimates with Cox regression analysis identified independent predictors. Result: The annualised LN incidence rate was 3.3, 3.1 1.9 and 0.4 for Asian (n = 29), Indigenous Australian (IA) (n = 11), other (n = 9), and Caucasians (n = 43) (all P < 0.01 vs Caucasian). There was no significant difference between ethnic groups regarding ISN class (proliferative 66%, membranous19% or mesangial 15%), proteinuria (median PCR 300 mg/mmol), increased serum creatinine (31%), renal (median 8) and non‐renal SLEDAI (median 4), anti‐dsDNA antibodies (89%) or hypocomplementemia (88%). Treatment included corticos- teroids (91%), cyclophosphamide (30%), mycophenolate (67%) and antihypertensive drugs (67%). Five and ten years survival was 95% % at both time points for Caucasians and Asians and 81% and 70% in IA (P = 0.016). Five and ten‐year renal survival (endpoint RRT) was 100% for Asian, 100% and 96% for Caucasian, vs 86% and 64% for IA (P = 0.02). Ethnic background was the only independent pre- dictor for poor patient survival and together with male gender also predictive of poor renal survival. Conclusion: The majority of adult LN patients in WA now are non‐ Caucasian. Despite a high incidence of LN, Asian LN patients have similar favourable outcomes as Caucasians, while the outlook is much bleaker for IA patients. As histological and clinical findings did not predict outcome, other factors are responsible for this disparity.