Reliability of Freestyle Libre

Hello, Summarians!

As Freestyle Libre use becomes the standard of care, it is always nice to look at studies that help us understand its potential uses and limitations.

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Mortality of Perioperative Ventricular Arrhythmias in Dogs

The study aimed to identify risk factors for perioperative ventricular arrhythmias (VAs) and in-hospital mortality in dogs undergoing splenectomy for splenic masses. The hypotheses were focused on factors like low packed cell volume (PCV) or hematocrit (Hct), low platelet count, presence of hemoperitoneum, and the diagnosis of hemangiosarcoma being associated with increased risk of VAs, and the presence of VAs being linked to higher in-hospital mortality rates. The study found that the presence of hemoperitoneum, higher body weight, and higher heart rate on presentation were associated with increased odds of experiencing intra- and postoperative VAs. Hemoperitoneum was a particularly significant risk factor for VAs and also for in-hospital mortality. The study also noted that while the presence of VAs was associated with an increased odds of in-hospital mortality, the overall mortality rate for dogs undergoing splenectomy for splenic masses remained relatively low (6.5%), suggesting a generally favorable prognosis despite the occurrence of VAs or hemoperitoneum. It's worth noting that the study had some limitations, including its retrospective nature and potential underreporting or misclassification of arrhythmias in medical records. In summary, the study highlighted the significant association between hemoperitoneum, higher body weight, and higher heart rate on presentation with the development of ventricular arrhythmias in dogs undergoing splenectomy for splenic masses. Additionally, it emphasized that the presence of ventricular arrhythmias was linked to an increased risk of in-hospital mortality, but the overall prognosis for these dogs undergoing surgery remained relatively positive. 

Michael, A. E., Grimes, J. A., Rajeev, M., Wallace, M. L., & Schmiedt, C. W. (2023). Perioperative ventricular arrhythmias are increased with hemoperitoneum and are associated with increased mortality in dogs undergoing splenectomy for splenic masses. Journal of the American Veterinary Medical Association https://doi.org/10.2460/javma.23.05.0289 

Bottom line — Increased mortality in hospitalized cases but still low (6.5%) overall

Reliability of Freestyle Libre in Cats

This text discusses the use and accuracy of continuous glucose monitoring devices, specifically the FreeStyle Libre 2 (FSL2), in monitoring the glucose levels of cats, particularly in the hypoglycemic range (low blood sugar levels). The authors conducted a study to assess the accuracy of FSL2 in comparison to blood glucose measurements (BG) during periods of induced hypoglycemia in cats. The study aimed to determine whether interstitial glucose (IG) measurements from the FSL2 accurately reflected blood glucose levels during these critical low blood sugar situations. The study found that there was a proportional bias between IG and BG measurements in the FSL2 during various glycemic ranges. While the FSL2 tended to underestimate blood glucose levels in most of the euglycemic (normal blood sugar) and hyperglycemic (high blood sugar) ranges, it tended to overestimate blood glucose levels in the hypoglycemic range below 60 mg/dL. This indicated that the accuracy of the FSL2 readings was influenced by the glycemic level, and the discrepancy between IG and BG measurements was not a fixed bias but rather depended on the severity of hypoglycemia. The authors concluded that clinicians and cat owners should be aware of this glycemic-dependent bias in the FSL2 when interpreting glucose measurements, especially in severely hypoglycemic situations. The findings highlighted the importance of understanding the limitations of continuous glucose monitoring devices and using them cautiously, particularly when making critical clinical decisions based on glucose measurements. Overall, the study provided valuable insights into the accuracy of continuous glucose monitoring devices in feline patients, specifically in the context of hypoglycemia, and underscored the need for careful interpretation of glucose data in various glycemic ranges. 

Berg, AS, Crews, CD, Adin, C, et al. Assessment of the FreeStyle Libre 2 interstitial glucose monitor in hypo- and euglycemic cats. J Vet Intern Med. 2023; 37(5): 1703-1709. doi:10.1111/jvim.16820 

Bottom line — Underestimated in euglycemic or hyperglycemic states but overestimated at levels below 60 mg/dl

Vitamin E and arthritis in dogs

Osteoarthritis (OA) is a common and painful condition affecting dogs, and traditional treatments using nonsteroidal anti-inflammatory drugs (NSAIDs) have limitations due to potential adverse effects. Vitamin E (VE) has been considered as an alternative treatment for OA due to its antioxidant and anti-inflammatory properties. Previous studies in humans and dogs have suggested potential benefits of VE supplementation in reducing inflammation, pain, and cartilage damage associated with OA. However, the efficacy of VE in treating OA in dogs has not been definitively established. A study was conducted to investigate the effects of VE supplementation in dogs with naturally occurring OA. The study aimed to assess whether VE supplementation could improve quality of life (QOL), reduce pain and lameness, decrease the need for pain medications, and lower C-reactive protein (CRP) concentrations or liver enzyme activity in dogs with OA. The results of the study showed that VE supplementation did not lead to significant improvements in QOL, lameness, pain, or clinical pathology variables when compared to a placebo. While there was some improvement in QOL during the first 60 days of the study, the overall effects were not statistically significant. Furthermore, VE supplementation did not lead to a decrease in pain medication requirements or CRP concentrations. The study's findings were different from previous research that suggested potential benefits of VE supplementation in dogs with OA. Possible reasons for the discrepancies include the chronic nature of the OA in the study dogs compared to acute inflammation seen in other studies, variations in the formulation of the VE supplement, and limitations of the assessment methods used. The study concluded that based on its results, VE supplementation at a dosage of 400 IU per day did not provide significant clinical benefits for dogs with naturally occurring OA. However, the study also noted potential limitations in its design and suggested that further research, particularly involving more acute inflammatory joint conditions and objective assessment methods, is needed to better understand the potential benefits of VE supplementation for dogs with OA. In essence, while there is interest in exploring alternative treatments like VE for OA in dogs, the study suggests that VE supplementation may not be a reliable or effective option for managing the condition. Further research is required to establish the role of VE or other potential therapies in alleviating the symptoms and improving the quality of life for dogs with OA. 

Gordon, CL, Reeves, SJ, Burchell, RK, et al. A blinded, placebo-controlled study on the clinical effects of vitamin E supplementation in dogs with osteoarthritis. J Vet Intern Med. 2023; 37(5): 1839-1847. doi:10.1111/jvim.16816 

Bottom line — Not effective in helping with arthritis symptoms in dogs.

Just putting things in perspective …