A urine protein creatinine ratio (UPC) of >2.0 has historically been taken to indicate glomerular disease in the dog. However, recent literature has questioned whether this cutoff remains appropriate. When glomerular disease is suspected, standard therapy (which usually includes an angiotensin converting enzyme inhibitor, ACEi) has been recommended to try to reduce the magnitude of the associated proteinuria. Despite these standard therapies being widely implemented, the proportion of dogs that respond is unknown. Additionally, whether response to standard treatment conveys significant survival benefit is undetermined.

This master’s project was comprised of a retrospective and prospective study. The retrospective study aimed to assess the number of dogs that respond to treatment with ACEi and determine if response to treatment conveyed survival benefit. Additionally, the retrospective study assessed if the presence of baseline clinicopathological abnormalities impacted survival. The prospective study aimed to determine the proportion of dogs with a UPC of >2.0 that had tubular proteins present on urine protein electrophoresis (UPE) and determine the significance of the presence of such proteins. UPE patterns were also assessed to determine if dogs with and without an identifiable trigger for their proteinuria could be differentiated between. Urinary biomarkers of tubular damage (GGT and NGAL) were also measured to further evaluate for tubular involvement. Finally, we also aimed to mirror the retrospective study and screen for potential prognostic indicators.

The retrospective study demonstrated that although 2.0 had evidence of tubular proteins on UPE and presence of such proteins may suggest more advanced disease. The presence of tubular damage was further demonstrated by measurement of NGAL which was elevated in nearly all dogs. We found that the UPE pattern could not be used to distinguish between dogs with and without a trigger for their proteinuria. Evaluation of clinicopathological variables from the prospective population of dogs mirrored the results of the retrospective study with regard to prognostic implications; additionally, dogs with a mixture of glomerular and tubular proteins present were found to have a worse prognosis than those with just glomerular proteins present.

The results of this master’s project go towards filling previous knowledge gaps within the field of canine glomerular disease and further our understanding of this complex condition.