Histopathology pattern and survival analysis of patients with kidney biopsy in the top end of Northern Australia from 2007 to 2020.

Aim: Royal Darwin Hospital (RDH) is the main tertiary hospital that has performed more than 600 biopsies since its establishment. Although Indigenous people in Australia's Northern Territory (NT) has the highest rate of renal replacement therapy, the histopathology pattern of their renal diseases is still under discussed. We aimed to analyse the histopathology pattern of patients undergoing renal biopsy in RDH from June 2007 to June 2020. Secondary aims include clinical indication and survival analysis of patients with kidney biopsies.

Methods: We conducted a retrospective cohort study on all native kidney biopsy reports from patients over the age of 16, from June 2007 to June 2020. Descriptive statistics was used to summarise age, sex, indigeneity, histopathological pattern, and mortality. Categorical values were expressed as absolute frequencies and percentages. Survival analysis was performed using multivariate analyses and Cox proportional hazard regression model.

Results: There were 364 native renal biopsies included in the analysis. Sub-nephrotic proteinuria was the most common clinical indication for kidney biopsy (n = 160,47.8%). Diabetes nephropathy (DN) was the most common pathological finding (n = 71,12.8%). Indigenous population who had dialysis performs poorly compared to their non-indigenous counterpart (HR 2.37,95% CI 1.53-3.67,p < 0.001).

Conclusion: Diabetic nephropathy is the most common native kidney biopsy in the NT with higher mortality among indigenous patients. This study supports the previous findings of indigenous female excess, younger age of kidney disease requiring kidney biopsy, and excess of diabetic nephropathy in the top-end of the NT. It can be speculated that some diabetic patients had atypical features prompting a biopsy.