Clinical and Pathologic Characterization of Proteinuric Kidney Disease in Australian and New Zealand Dogs

ABSTRACT Background The prevalence of immune complex‐mediated glomerulonephropathy (ICGN) in dogs with proteinuric kidney disease is approximately 50% in the United States and Europe but is unknown in other locations such as Australia and New Zealand. Objectives Determine the prevalence of ICGN in dogs biopsied for proteinuric kidney disease in Australia and New Zealand and compare clinicopathologic variables in dogs with specific pathologic lesions. Animals Fifty client‐owned dogs. Methods Retrospective case series. Reports from renal biopsy samples submitted to the Texas and International Veterinary Renal Pathology Services from dogs with proteinuric kidney disease (urine protein‐to‐creatinine ratio ≥ 0.5) between 2007 and 2023 were reviewed. Clinical data were retrieved and compared. Results Among 50 dogs with proteinuric renal disease, 15 dogs (30%) had ICGN and 35 (70%) had non‐ICGN. The most common category of ICGN was membranous glomerulonephropathy (6/15; 40%). Glomerulosclerosis was the most common category of non‐ICGN (17/35; 49%). Dogs with glomerulosclerosis (median, 10 years) were older than dogs with other types of lesions (membranoproliferative, mesangioproliferative or mixed pattern; median, 6 years; p = 0.04) and those with membranous glomerulonephropathy (median, 4 years; p = 0.005). Dogs with membranous glomerulonephropathy had lower serum albumin concentrations (median, 2.1 g/dL) than dogs with glomerulosclerosis (median, 3.0 g/dL; p = 0.01) or other nephropathies (median, 3.0 g/dL; p = 0.04). Conclusions and Clinical Importance The prevalence of ICGN is lower in dogs in Australia and New Zealand biopsied for proteinuric kidney disease, potentially because of a lower prevalence of infectious disease, particularly vector‐borne disease. The lower prevalence of ICGN emphasizes the importance of renal biopsy to optimize treatment.