Survival of dogs with glomerular disease in Europe: insights from the European Veterinary Renal Pathology Service.

BACKGROUND: Although glomerular disorders contribute to chronic kidney disease in dogs, few studies have evaluated the usefulness of renal biopsy for predicting outcome. HYPOTHESIS/OBJECTIVES: Investigate morphologic diagnoses, clinicopathological findings, comorbidities, treatment, and their associations with survival in dogs after renal biopsy. ANIMALS: One hundred ten client-owned dogs with glomerular disease. METHODS: Retrospective cohort study of medical records from the European Veterinary Renal Pathology Service (2018-2023). Data were obtained before referral for renal biopsy and during follow-up. Survival analysis was performed using the Kaplan-Meier method, followed by log-rank tests. Relative risk was calculated using contingency tables. RESULTS: Dogs were classified into 3 groups: immune complex glomerulonephritis (ICGN) (61 dogs, 56%), non-ICGN (39 dogs, 35%), and juvenile nephropathy (JN) (10 dogs, 9%). Survival was longer in ICGN dogs than non-ICGN (mean ± SEM: 951 ± 78 days vs. 613 ± 92 days; P = .02), with no difference versus JN (1004 ± 169). No survival differences were observed among the morphological subtypes of ICGN. Dogs with amyloidosis had shorter survival than all other morphologic non-ICGN subtypes (384 ± 95 vs. 650 ± 56 days, P = .02). Risk of a creatinine increase of ≥50% during follow-up was greater in the JN group (RR = 2.78; 95% CI, 1.60-4.84; P = .03). Reduction in proteinuria ≥50% during follow-up did not differ between groups. Immunosuppressive treatment was more frequently administered to ICGN dogs (P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: Immune complex glomerulonephritis dogs had better outcomes and slower disease progression than non-ICGN and JN. Proteinuria decreased by approximately 50% within each group over time; however, the retrospective design precludes conclusions regarding the effect of antiproteinuric treatment.