Background and aims Ethnicity impacts on disease frequency and severity in patients with Lupus Nephritis (LN). As such data are lacking for Indigenous Australians (IA), we investigated the epidemiology, histopathology and outcomes of biopsy proven LN in the Top End of the Northern Territory, Australia.

Methods All patients with biopsy confirmed LN between 2001 and January 2011 were identified from a central database at the Royal Darwin Hospital. Demographics and renal histopathology at first renal biopsy (ISN classification, NIH activity (AI) and chronicity index (CI), immunofluorescence (IF) and electron dense deposit (EDD)) were recorded. Clinical findings and outcomes were retrieved by chart review.

Results The total study cohort (n=42, age 30 years; 86% female) included 31 IA patents (74%). The annual LN incidence was 7/100,000 in IA patients versus 0.7/100,000 in non-indigenous (NI) patients (p<0.01).

Proliferative LN (class III+IV) was less frequent in IA patients (42% vs. 72%) (p<0.01), but AI (2 vs. 5, p=0.06) and CI (2 vs. 1, p=0.9) scores did not differ significantly.

Five and ten year patient survival rates were 69% and 50% for IA and 90% for NI patients, while renal survival was 87% and 53% in IA patients and 100% in NI patients. The leading causes of death were infections (38.6%), end stage renal disease (23%), cardiovascular events (15.4%).

Conclusions Biopsy proven LN occurs much more frequently in the IA than in the Causcasion population. While associated with poor patient and renal survival, this is not explained by the histological severity of LN.