Pilot study evaluating the monitoring of canine diabetes mellitus in primary care practice

Short-term glycemic variability in non-diabetic, non-obese dogs assessed by common glycemic variability indices

Glycemic variability (GV) refers to swings in blood glucose levels and is an emerging measure of glycemic control in clinical practice. It is associated with micro- and macrovascular complications and poor clinical outcomes in diabetic humans. Although an integral part of patient assessment in human patients, it is to a large extent neglected in insulin-treated diabetic dogs. This prospective pilot study was performed to describe canine within-day GV in non-diabetic dogs with the aim to provide a basis for the interpretation of daily glucose profiles, and to promote GV as an accessible tool for future studies in veterinary medicine. Interstitial glucose concentrations of ten non-diabetic, non-obese beagles were continuously measured over a 48-h period using a flash glucose monitoring system. GV was assessed using the common indices MAGE (mean amplitude of glycemic excursion), GVP (Glycemic variability percentage) and CV (coefficient of variation). A total of 2260 sensor measurements were obtained, ranging from 3.7 mmol/L (67 mg/dL) to 8.5 mmol/L (153 mg/dL). Glucose profiles suggested a meal-dependent circadian rhythmicity with small but significant surges during the feeding periods. No differences in GV indices were observed between day and night periods (p > 0.05). The MAGE (mmol/L), GVP (%) and CV (%) were 0.86 (± 0.19), 7.37 (± 1.65), 6.72 (± 0.89) on day one, and 0.83 (± 0.18), 6.95 (± 1.52), 6.72 (± 1.53) on day two, respectively. The results of this study suggest that GV is low in non-diabetic dogs and that glucose concentrations are kept within narrow ranges.

Canine diabetes mellitus demonstrates multiple markers of chronic inflammation including Th40 cell increases and elevated systemic-immune inflammation index, consistent with autoimmune dysregulation

Introduction

Canine diabetes mellitus (CDM) is a relatively common endocrine disease in dogs. Many CDM clinical features resemble human type 1 diabetes mellitus (T1DM), but lack of autoimmune biomarkers makes calling the disease autoimmune controversial. Autoimmune biomarkers linking CDM and T1DM would create an alternative model for drug development impacting both human and canine disease.

Methods

We examined peripheral blood of diagnosed CDM dog patients comparing it to healthy control (HC) dogs. Dogs were recruited to a study at the Colorado State University Veterinary Teaching Hospital and blood samples collected for blood chemistry panels, complete blood counts (CBC), and immunologic analysis. Markers of disease progression such as glycated albumin (fructosamine, the canine equivalent of human HbA1c) and c-peptide were addressed.

Results

Significant differences in adaptive immune lymphocytes, innate immune macrophages/monocytes and neutrophils and differences in platelets were detected between CDM and HC based on CBC. Significant differences in serum glucose, cholesterol and the liver function enzyme alkaline phosphatase were also detected. A systemic immune inflammation index (SII) and chronic inflammation index (CII) as measures of dynamic changes in adaptive and innate cells between inflammatory and non-inflammatory conditions were created with highly significant differences between CDM and HC. Th40 cells (CD4+CD40+ T cells) that are demonstrably pathogenic in mouse T1DM and able to differentiate diabetic from non-diabetic subjects in human T1DM were significantly expanded in peripheral blood mononuclear cells.

Conclusions

Based on each clinical finding, CDM can be categorized as an autoimmune condition. The association of significantly elevated Th40 cells in CDM when compared to HC or to osteoarthritis, a chronic but non-autoimmune disease, suggests peripheral blood Th40 cell numbers as a biomarker that reflects CDM chronic inflammation. The differences in SII and CII further underscore those findings.

Long-term field study of lispro and neutral protamine Hagedorn insulins treatment in dogs with diabetes mellitus

BACKGROUND

The long-term clinical and biofhemical effects of basal-bolus insulin treatment with lispro and NPH in dogs with diabetes mellitus are undocumented.

OBJECTIVES

To perform a prospective pilot field study of the long-term effects of lispro and NPH on clinical signs and serum fructosamine concentrations (SFC) in dogs with diabetes mellitus.

METHODS

Twelve dogs received combined lispro and NPH insulins treatment twice a day and were examined every 2 weeks for 2 months (visits 1-4), and every 4 weeks for up to 4 additional months (visits 5-8). Clinical signs and SFC were recorded at each visit. Polyuria and polydipsia (PU/PD) were scored as absent (0) or present (1).

RESULTS

Median (range) PU/PD scores of combined visits 5-8 (0, 0-1) were significantly lower than median scores of combined visits 1-4 (1, 0-1, p = 0.03) and at enrolment (1, 0-1, p = 0.045). Median (range) SFC of combined visits 5-8 (512 mmol/L, 401-974 mmol/L) was significantly lower than SFC of combined visits 1-4 (578 mmol/L, 302-996 mmol/L, p = 0.002) and at enrolment (662 mmol/L, 450-990 mmol/L, p = 0.03). Lispro insulin dose was significantly and negatively, albeit weakly, correlated with SFC concentration during visits 1 through 8 (r = -0.3, p = 0.013). Median duration of follow up was 6 months (range 0.5-6) and most dogs (8, 66.7%) were followed for 6 months. Four dogs withdrew from the study within 0.5-5 months because of documented or suspected hypoglycaemia, short NPH duration or sudden unexplained death. Hypoglycaemia was noted in 6 dogs.

CONCLUSIONS

Long-term lispro and NPH combination therapy may improve clinical and biochemical control of some diabetic dogs with comorbidities. Risk of hypoglycaemia should be addressed with close monitoring.

Clinical utility of serum fructosamine in long-term monitoring of diabetes mellitus in dogs

BACKGROUND

Serum fructosamine (sFA) is used to assess glycaemic control in dogs with diabetes mellitus (DM). Nevertheless, its interpretation is hindered by several limitations.

METHODS

This retrospective study evaluates the long-term diagnostic performance of sFA for monitoring clinical control of DM. sFA, bodyweight, appetite, presence of polyuria/polydipsia and clinical scores (CS; well-controlled DM, CS-0; uncontrolled DM, CS-1) were recorded.

RESULTS

The study included 75 dogs (321 visits; median 3 visits/dog; range 1-19). Mean sFA was higher (p < 0.001) on visits with CS-1 (584 μmol/L; 95% confidence interval [95% CI] 561-608) than on visits with CS-0 (506 μmol/L; 95% CI 484-528). Increases in sFA increased   the odds ratio for CS-1 (1.37; 95% CI 1.24-1.52, p < 0.001). sFA was moderately predictive of the CS (area under receiver operating characteristic curve = 0.75; 95% CI 0.70-0.80; p < 0.0001), with a 486 μmol/L cutoff yielding 80% sensitivity and 59% specificity. Mean sFA was lower (p = 0.005) when hypoglycaemic episodes were suspected (496 μmol/L; 95% CI 450-541) than in their absence (572 μmol/L; 95% CI 548-596). sFA is moderately accurate for classifying CS in diabetic dogs. Decreasing sFA over follow-ups indicates improved CS but might suggest occurrence of hypoglycaemic episodes.

LIMITATIONS

Retrospective design, variable treatments and comorbidities are limitations of this study.

CONCLUSION

sFA has a moderate clinical utility in the long-term monitoring of diabetic dogs, but may serve as a first-line, accessible diagnostic tool. Discordant CS and sFA evaluation, or decreased sFA, warrants additional monitoring (i.e., continuous glucose monitoring).

Evaluation of fructosamine concentration as an index marker for glycaemic control in diabetic dogs

BACKGROUND

Although fructosamine is a commonly used surrogate marker to assess glycaemic control in diabetic dogs, its diagnostic accuracy has been questioned. The main objective of this study was to evaluate the reliability of fructosamine measurements to diagnose well and poorly controlled diabetes mellitus (DM), using continuous glucose monitoring as a gold standard.

METHODS

Twenty-four dogs with treated DM and continuous glucose monitoring for mean (±SD) 13.1 (±1.7) days were retrospectively analysed. Two assessment strategies were applied to categorize glycaemic control, and fructosamine concentrations were determined shortly after sensor cessation using a colorimetric assay.

RESULTS

Correlations of individual fructosamine concentrations with mean glucose as well as percentage of measurements > 15 mmol/L were not significant (p = 0.372, p = 0.129). Fructosamine did not differ between dogs with and without hypoglycaemic episodes (p = 0.64). Receiver operating characteristic analysis for fructosamine to diagnose either good or poor glycaemic control revealed AUC values of 0.71 (p = 0.025) indicating moderate accuracy, and 0.7 (p = 0.135) indicating AUC is non-discriminatory, respectively. The respective positive likelihood ratios for the optimal cutoffs to identify good (<396 μmol/L) and poor control (>449 μmol/L) were three.

CONCLUSIONS

Fructosamine measurement is an imperfect surrogate marker for classifying glycaemic control in diabetic dogs and can only complement serial glucose measurements.

Flash glucose monitoring in diabetic dogs: a feasible method for evaluating glycemic control

OBJECTIVE

To alleviate clinical signs and avoid life-threatening complications in dogs with diabetes mellitus, individualized treatment plans and frequent reassessments are necessary. Performing blood glucose profiles every 7-14 days following insulin adjustments and monthly thereafter, is recommended. In 2016, a factory calibrated continuous blood glucose monitoring system was presented as a possible alternative to glucometer readings. The objectives of this study were to summarize the experiences with this new technology and to show, that in combination with simple rules, already the first measurement period can improve glycemic control.

MATERIAL AND METHODS

The electronic database of the endocrine unit of the clinic was retrospectively searched for diabetic dogs with flash glucose monitoring. In case of repeated sensor implantations, only the first sensor was considered. The recordings of day A (starting at midnight after sensor placement) were compared to the measurements of day B (day before sensor failure) and all owners were contacted to fill in a standardized questionnaire.

RESULTS

The final study population consisted of 24 dogs weighing 3.4 to 36 kg. Although the clicking noise during sensor placement irritated most dogs, the application was considered easy and painless. Waiting for disinfectant evaporation and fixation of the sensor disc with forceps helped to avoid sensor detachment when removing the application device. Although transient mild to moderate skin irritations were observed in 80 % of the dogs, 95 % of the owners were highly satisfied with this new monitoring technology. Mean and maximum glucose (p = 0.043, p = 0.003) as well as glucose readings ≥ 11.1 mmol/l (p = 0.032) decreased from day A to B, whereas markers of glycemic variability did not change.

CONCLUSION AND CLINICAL RELEVANCE

Flash glucose monitoring is a feasible, safe method with high user satisfaction and offers a possibility to improve glycemic control in diabetic dogs.