The purpose of this study was to compare the efficacy and safety of using two commercially available, low-magnesium, urine-acidifying dry foods to dissolve sterile struvite uroliths in cats.
In a randomized clinical trial, 37 cats with presumed stuvite uroliths were randomly assigned to be fed one of two low-magnesium, urine acidifying dry foods (food A or food B). For each cat, physical examination, urinalysis and abdominal radiography were performed weekly to assess treatment response. Thirty-two cats had complete urolith dissolution. Mean Â± SD times for a 50 percent reduction in urolith size and complete urolith dissolution were significantly shorter for cats fed food A, compared with those for cats fed food B. At study termination, mean Â± SD urine pH for cats fed food A was lower than that for cats fed food B. In five cats, uroliths did not dissolve and were subsequently determined to be composed of 100 percent ammonium urate or 100 percent calcium oxalate. Adverse events associated with diet were not observed in any of the cats.
Results indicated that dietary dissolution is safe and effective for eradication of sterile struvite uroliths in cats. Cats fed food A had faster urolith dissolution than did cats fed food B. Lack of a reduction in urolith size at two weeks after diet initiation was indicative of misdiagnosis or noncompliance.
Source: Jody P. Lulich et al., 2013. Efficacy of two commercially available, low-magnesium, urine-acidifying dry foods for the dissolution of struvite uroliths in cats. JAVMA online, October 2013. doi: 10.2460/javma.243.8.1147.