Urolithiasis is a common cause of feline lower urinary tract disease (FLUTD). The most common feline uroliths are calcium oxalate and struvite. Dietary dissolution is safe and effective for eradication of sterile struvite uroliths in cats. Richness in moisture and/or sodium and/or protein in order to increase water intake and thus to increase diuresis, urinary flow and the frequency of micturition may vary between commercially diets. This prospective, multicenter, randomized, double-blinded clinical trial evaluated the efficacy and safety of two new high-protein, low-carbohydrate dry diets in sterile, struvite urolithiasis in cats with signs of non-obstructive FLUTD.

Cats enrolled in the study were randomly assigned either to diet A,¹ formulated to achieve dissolution and prevention of struvite uroliths, or to diet B,² formulated to dissolve struvite uroliths. Cats were followed up to 14 days after the uroliths had been dissolved, latest to D56±2. Physical examination, urinalysis, and abdominal ultrasound were performed weekly. Analyses were performed using the software SAS® version 9.4. The significance threshold was set to α=0.05 two-sided.

Thirty-three cases were recruited and supplied with diet A (n=17) or diet B (n=16) according to the randomization procedure. The mean time of struvite dissolution was 13.1 days and 14 days respectively for diet A and diet B (n.s). The mean time to disappearance of at least one urinary sign was 7 days for diet A and 11.4 days for diet B (p=0.03). On D7, all cats from group A and 75% of cat from group B had no more urinary signs (p=0.04). Mean urinary pH was decreased in groups A and B at the end of the study (6,1±0.5 and 6±0.6, respectively) compared to D0 (7,2±0.8 and 7,2±0.7, respectively). In group B, urine specific gravity significantly decreased (p=0.01) from D0 (1.046±9.8) to the end of the study (1.036±12.5). In group A, urine specific gravity decrease was not significant. Two and 4 cats of groups A and B respectively exhibited transitory adverse events, possibly related to the diet (mild diarrhea or mild vomiting). These events resolved spontaneously and did not lead to the exclusion of any cat.

The new high-protein, low-carbohydrate tested diets were effective for dissolution of feline struvite urolithiasis.

Disclosures

Disclosures to report
This study was founded by Virbac. Three co-authors are employees of Virbac.