Evaluation of the FreeStyle Libre 3 in client-owned diabetic cats

The FreeStyle Libre 3 (FSL3) continuous glucose monitoring system (CGMS) is accurate in diabetic people, and its smaller size could be advantageous in veterinary patients.

Assess the clinical and analytical accuracy, sensor lifespan, and frequency of complications of the FSL3 in diabetic cats.

Twenty client-owned diabetic cats.

Interstitial glucose concentrations (IG) measured using the FSL3 were compared to blood glucose concentrations (BG) measured using the AlphaTRAK2. Skin reactions at the application site and sensor lifespan were recorded. Spearman's correlation coefficient, Bland-Altman test, and Parkes error grid analysis (EGA) were used to evaluate correlation, bias, and clinical accuracy, respectively. Analytical accuracy was assessed using the mean absolute relative difference (MARD).

Median sensor lifespan was 11 days (range, 4-14). After sensor removal, 4 cats had a mild erythema at the application site. A total of 288 paired IG-BG measurements were recorded, the majority of which (279/288, 97%) were in the euglycemic (70-180 mg/dL) and hyperglycemic (>180 mg/dL) ranges. A strong positive correlation was observed between IG and BG readings (rs = 0.95; < 0.0001). Comparison of IG and BG measurements resulted in a MARD of 13.6% and an overall negative bias of -19.4 ± 46.0 mg/dL. Clinical accuracy was demonstrated, with 99.7% (287/288) of the results in zones A + B of the Parkes EGA.

FreeStyle Libre 3 provides clinically accurate measurements in the euglycemic and hyperglycemic ranges in diabetic cats. The smaller size of the FSL3 may improve adherence and long-term use of CGMS in diabetic cats.