Resumen de Evaluation for association between urolithiasis and chronic kidney disease in cats
Andréanne Cléroux, Kate Alexander, Guy Beauchamp, Marilyn Dunn
OBJECTIVE To determine whether urolithiasis is associated with chronic kidney disease (CKD) in cats.
DESIGN Retrospective case-control study.
ANIMALS 126 cats (59 and 67 with and without urolithiasis, respectively).
PROCEDURES Medical records from June 2006 to July 2013 were searched to identify cats that underwent abdominal or focal urinary tract ultrasonography and for which serum creatinine concentration and urine specific gravity data were obtained ≤ 14 days before or after the examination. In cats with (urolithiasis group) and without (control group) urolithiasis, the presence of CKD was determined according to International Renal Interest Society guidelines. Information recorded included signalment, body weight, serum creatinine concentration, and urine specific gravity; when present, the location and number of uroliths were noted. Differences between groups and associations between group and categorical variables were analyzed statistically.
RESULTS Age, weight, sex, and breed did not differ between groups. The prevalence of CKD was significantly higher in cats with urolithiasis than in the control group. Among cats with urolithiasis, there was a negative association between CKD and presence of cystoliths. There was no association between urolithiasis and the stage of CKD or between presence of CKD and location of nephroliths in the kidney.
CONCLUSIONS AND CLINICAL RELEVANCE Results confirmed a positive association between urolithiasis and CKD in the feline population studied and suggested that cats with urolithiasis should be evaluated for CKD. Further research is warranted to assess the nature of the relationship between CKD and urolithiasis in cats.
Chronic kidney disease is a common condition in geriatric cats and an important cause of illness and death in this species.1 The mean age of affected cats ranges from 9 to 12 years depending on the population examined, and the prevalence of the disease increases with age.2 Chronic kidney disease is a degenerative condition that often results from chronic tubulointerstitial nephritis of unknown etiopathogenesis.3 The IRIS has developed guidelines for staging of CKD on the basis of blood creatinine concentration.4 Staging has allowed for determination of disease severity and for treatment strategies to be implemented according to the stage of disease.3,4 The general goals of treatment are to slow the progressive loss of kidney function by addressing underlying or concurrent disease processes, improve clinical and biochemical consequences of CKD, and maintain adequate nutrition.5 However, few studies have described risk factors for the development and progression of CKD in cats.6 In a large cross-sectional analysis, CKD was found to affect approximately 13% of people in the United States, and prevalence of the disease from 1999 to 2004 was higher than it was from 1988 to 19947 Urolithiasis and, more specifically, nephrolithiasis, are recognized as risks factors for CKD in human patients. Patients with CKD were found to have 1.9 times the odds of a previous diagnosis of urolithiasis as were matched control patients without CKD,8 and a history of nephrolithiasis was found to be associated with an increased risk of CKD and end-stage renal failure in people.9 Theories have been proposed to explain the formation of uroliths in cats, and various risk factors for the development of urolithiasis have been proposed.10–13 Calcium oxalate and struvite uroliths are most commonly identified in cats.11 To the authors' knowledge, an association between CKD and urolithiasis in cats has not previously been established.
The veterinary literature regarding risk factors associated with the development and progression of CKD in cats is sparse. The purpose of the study reported here was to investigate whether an association exists between urolithiasis and CKD in cats. We hypothesized that there would be a positive association between urolithiasis and CKD in the feline population evaluated.
