Background
Cats presenting with upper urinary tract uroliths (UUTUs) and ureteral obstruction (“obstructive UUTU”) are typically younger than cats with idiopathic CKD that often have incidental nephroliths.
Hypothesis
Cats with upper urinary tract urolith have 2 clinical phenotypes; a more aggressive phenotype at risk of obstructive UUTU at a young age and a more benign phenotype in older cats, with reduced risk of obstructive UUTU.
Objectives
Identify risk factors for UUTU and for obstructive UUTU.
Animals
Eleven thousand four hundred thirty‐one cats were referred for care over 10 years; 521 (4.6%) with UUTU.
Methods
Retrospective VetCompass observational cross‐sectional study. Multivariable logistic regression models were performed to identify risk factors for a diagnosis of UUTU vs no UUTU and additionally, obstructive UUTU vs nonobstructive UUTU.
Results
Risk factors for UUTU included female sex (odds ratio [OR] 1.6, confidence interval [CI] 1.3‐1.9;
P
< .001), British shorthair, Burmese, Persian, Ragdoll or Tonkinese (vs non‐purebred ORs 1.92‐3.31;
P
< .001) breed and being ≥4 years (ORs 2.1‐3.9;
P
< .001). Risk factors for obstructive UUTU were female sex (OR 1.8, CI 1.2‐2.6;
P
= .002), having bilateral uroliths (OR 2.0, CI 1.4‐2.9;
P
= .002) and age, with the odds of obstructive UUTU increasing as age at diagnosis of UUTU decreased (≥12 years, reference category; 8‐11.9 years, OR 2.7, CI 1.6‐4.5; 4‐7.9 years, OR 4.1, CI 2.5‐7.0; 0‐3.9 years, OR 4.3, CI 2.2‐8.6;
P
< 0.001).
Conclusions and Clinical Importance
Cats diagnosed with UUTU at a younger age have a more aggressive phenotype with higher risk of obstructive UUTU compared to cats over 12 years of age diagnosed with UUTU.