Background: Subclinical bacteriuria (SB) and pyuria (SP) are recognized in companion animals, yet their prevalence and comorbidities in those without signs of lower urinary tract disease (LUTD) remain underexplored.
Hypothesis/objectives: Determine SB and SP prevalence, identify associations, and compare species differences.
Animals: Two hundred eighty-seven cats and 533 dogs without LUTD signs.
Methods: Prospective cross-sectional study with retrospective analysis of medical records.
Results: Subclinical bacteriuria prevalence was 6.67% in cats and 9.81% in dogs. Subclinical pyuria was rarer in cats (1.05%) than in dogs (2.88%). Concurrent SB and SP occurred in 0.3% of cats and 2.5% of dogs (P = .0275), highlighting species-specific patterns. Higher urinary white blood cell levels were associated with higher urine bacterial levels (P < .001). In cats, key multivariable logistic regression associations increasing the composite outcome variable (SP, SB, or SP and SB) odds included previous diagnoses of lower urinary tract infection (LUTI; odds ratio [OR] 5.6 [95% confidence limit or 95CL 2-15.6), diabetes mellitus (OR 6.5 [95CL 1.4-30.3]), hyperthyroidism (OR 9.6 [95CL 1.2-77]), and current diagnosis of acute kidney injury (AKI; OR 7.5 [95CL 2.1-27]); in dogs, a previous diagnosis of AKI (OR 9.9 [95CL 1.3-76.9]), and current diagnoses of AKI (OR 9.9 [95CL 2.3-43.5]) and LUTI (OR 23.3 [95CL 12.5-43.5]). Machine learning revealed additional associations, including hypercortisolism in dogs.
Conclusions and clinical importance: These findings underscore distinct risk profiles between species, suggesting tailored diagnostic approaches in veterinary practice. The rarity of concurrent SB and SP, unlike in humans, questions the application of human guidelines to animals.
Keywords: comorbidity; companion animals; lower urinary tract disorders; machine learning; veterinary diagnostics.
© The Author(s) 2026. Published by Oxford University Press on behalf of the American College of Veterinary Internal Medicine.