Freestyle Libre-Derived Metrics in Assessing Glycemic Control in Diabetic Dogs

Background: The FreeStyle Libre provides several metrics that are currently recommended for assessing glycemic status and guiding therapy in human medicine. Hypothesis/Objective: To evaluate the use of various FreeStyle Libre derived metrics for monitoring glycemic control (GC) in diabetic dogs. Animals: Eighty-five client-owned dogs with diabetes mellitus (DM). Methods: A retrospective review of medical records was performed to search for dogs with DM on insulin treatment and monitored with FreeStyle Libre. To clinically assess GC, the Agreeing Language in Veterinary Endocrinology diabetic clinical score was used (ALIVE-DCS). Metrics evaluated were: percent time in range (TIR%), percent time above range (TAR%), percent time below range (TBR%), mean glucose (MG), percent coefficient of variation (CV%). Results: TIR%, TAR%, and MG were correlated with the ALIVE-DCS (rs = -0.35, p = 0.02; rs = 0.31, p = 0.038; rs = 0.36; p = 0.016, respectively). The CV% was correlated with MG (rs = -0.70, p < 0.0001). CV% was higher in dogs experiencing low IG values compared to dogs that did not (44% [19-65] vs. 28% [8-67]; p < 0.0001). Dogs with optimal GC had significantly lower MG (240 [108-411] vs. 290 mg/dL [155-478]; p = 0.006) and TAR% (48% [0-93] vs. 64% [12-100]; p = 0.006) and significantly higher TIR% (49.5% [7-100] vs. 35.0% [0-85]; p = 0.009) compared with dogs with sub-optimal GC. Conclusions and Clinical Importance: FreeStyle Libre derived metrics, particularly TIR%, TAR%, MG, and CV%, have potential utility in assessing GC in diabetic dogs.