Prevalence of Proteinuria in Dogs With Immune-Mediated Disease

Background: Proteinuria is associated with autoimmune diseases in humans. There is minimal evidence in the veterinary literature on proteinuria and its association with immune-mediated disease in dogs. Hypothesis: Renal proteinuria is common in dogs with immune-mediated disease. Dogs presenting with pyrexia or immune-mediated polyarthritis (IMPA) are more likely to have proteinuria. Animals: One hundred and forty-four dogs with primary immune-mediated diseases. Methods: Retrospective, observational study. Data collected included signalment, travel outside the United Kingdom, duration of clinical signs, diagnosis, urinalysis, and urine protein-creatinine ratio (UPCR). Non-proteinuric, mild proteinuria, moderate proteinuria, and severe proteinuria were defined as UPCR < 0.5; >= 0.5-1; >= 1-2; >= 2, respectively. Exclusion criteria included azotemia, hypoalbuminemia (< 2.0 g/dL), foreign travel, active urine sediment or positive culture, glucocorticoid therapy for greater than 24 h prior to presentation, or medication known to influence UPCR. Results: Sixty-seven dogs were non-proteinuric (47%; 95% confidence interval [95% CI]: 38%, 55%), 25 mildly proteinuric (17%; 95% CI: 9%, 26%), 15 moderately proteinuric (10%; 95% CI: 2%, 19%), and 37 severely proteinuric (26%; 95% CI: 17%, 34%). On multiple logistic regression analysis, female dogs (odds ratio [OR]: 3.24; 95% CI: 1.49, 7.42), individuals with pyrexia (OR: 6.59; 95% CI: 3.00, 15.37), or hemoglobinuria (OR: 27.21; 95% CI: 4.79, 516.56) were more likely to have proteinuria. There was an association between steroid-responsive meningitis-arteritis and the magnitude of proteinuria on multiple linear regression (p = 0.025); this was not confirmed on multiple logistic regression. Conclusions and Clinical Importance: Proteinuria is common in dogs with immune-mediated disease and can be severe. Screening for proteinuria could be considered part of the diagnostic assessment for dogs with immune-mediated disease.