Basal glucosuria in cats

Abstract

Objective of this study was to demonstrate the ubiquitous presence of glucose in urine of euglycemic cats by a highly sensitive glucose assay. The local electronic database was searched for results of quantitative urine glucose measurements in cats. A total of 325 feline urine glucose measurements were identified, of which 303 (93%) had been submitted by one of the co-authors working in a near-by small animal practice. After the exclusion of patients with kidney disease (n = 60), hyperthyroidism (n = 15), diabetes mellitus (n = 11), multiple diseases (n = 9) or steroid treatment (n = 3), as well as serial measurements (n = 87) and outliers (n = 8), the final study population consisted of 132 cats. Urine creatinine concentration was unavailable in five patients. Whereas all but one cat had glucose concentrations above the detection limit of the assay (0.11 mmol/L, Gluco-quant Enzyme Kit/Roche Diagnostics), no positive glucose dipstick test result (Combur 9-Test, Roche Diagnostics) was observed. The median (range) of urinary glucose concentration and the glucose-to-creatinine ratio (UGCR) was 0.389 (<0.11-1.665) mmol/L and 0.0258 (0.007-0.517) respectively. The UGCR was not affected by age, gender, breed or leukocyturia, whereas cats with hematuria had slightly higher values. Data show that so-called "basal glucosuria" is present in the majority of cats and by no means diagnostic for diabetes mellitus or renal glucosuria. This has to be considered when using bio-analytical methods with a low limit of quantification.

Keywords: cats; glucose; glucose-to-creatinine ratio; urine.

Figure 1

Distribution of urinary glucose concentrations in the 132 cats grouped according to gender. None of these cats had a positive glucose dipstick test result (lowest point estimate 2.78 mmol/L). The vertical dotted line represents the lowest point estimate of a sensitive modern urinary dipstick test (1.11 mmol/L)

Figure 2

Box plots of glucose‐to‐creatinine ratios in cats grouped according to IRIS stages 0–4