F. Tschuor

Evaluation of a new portable glucose meter designed for the use in cats

Portable blood glucose meters (PBGMs) are useful in the management of diabetes mellitus in cats. In the present study we compared the performance of two PBGMs: the AlphaTRAK (Abbott Animal Health, Maidenhead, England) specifically developed for dogs and cats, and the Ascensia ELITE (Bayer HealthCare, Zurich, Switzerland) developed for humans. Quality parameters, including precision and accuracy, were better for the AlphaTRAK meter compared to Ascensia ELITE. While the AlphaTRAK meter results did not differ from the reference method, results from the Ascensia ELITE were significantly (P<0.001) lower. The superior performance of the AlphaTRAK meter supports its use to monitor blood glucose levels in cats.

Remission of Diabetes Mellitus in Cats with Diabetic Ketoacidosis

BACKGROUND Diabetic ketoacidosis (DKA) has long been considered a key clinical feature of type-1 diabetes mellitus (DM) in humans although. An increasing number of cases of ketoacidosis have been reported in people with type-2 DM. HYPOTHESIS/OBJECTIVES Cats initially diagnosed with DKA can achieve remission from diabetes. Cats with DKA and diabetic remission are more likely to have been administered glucocorticoids before diagnosis. ANIMALS Twelve cats with DKA and 7 cats with uncomplicated DM. METHODS Retrospective case review. Medical records of cats presenting with DKA or DM were evaluated. Diabetic remission was defined as being clinically unremarkable for at least 1 month after insulin withdrawal. The cats were assigned to 1 of 3 groups: (1) cats with DKA and diabetic remission; (2) cats with DKA without diabetic remission; and (3) cats with DM and diabetic remission. RESULTS Seven cats with DKA had remission from diabetes. These cats had significantly higher concentrations of leukocytes and segmented neutrophils, and significantly lower concentrations of eosinophils in blood and had pancreatic disease more often than did cats with uncomplicated DM and diabetic remission. With regard to pretreatment, 3/7 cats in group 1, 1/5 cats in group 2, and 1/7 cats in group 3 had been treated with glucocorticoids. CONCLUSIONS AND CLINICAL IMPORTANCE Remission of DM in cats presenting with DKA is possible. Cats with DKA and remission have more components of a stress leucogram, pancreatic disease, and seemed to be treated more often with glucocorticoids than cats with uncomplicated DM and diabetic remission.

Evaluation of a novel real-time continuous glucose-monitoring system for use in cats

BACKGROUND The Guardian REAL-Time is a continuous glucose-monitoring system (CGMS) recently developed to provide instantaneous interstitial glucose concentrations; the system does not require a monitor being fixed to the animal. HYPOTHESIS The CGMS provides accurate and reproducible real-time readings of glucose concentration in cats. ANIMALS Thirty-two diabetic cats, 2 cats with suspected insulinoma, and 5 healthy cats. METHODS Prospective, observational study. CGMS accuracy was compared with a reference glucose meter at normal, high, and low blood glucose concentrations using error grid analysis. Reading variability of 2 simultaneously used CGMS was determined in diabetic cats by calculating correlation and percentage of concordance of paired data at different glycemic ranges. The time interval between increasing glycemia and a rise in interstitial fluid glucose measured by the CGMS was assessed in healthy cats receiving glucose IV; the time point of maximal increase in interstitial glucose concentrations was calculated. RESULTS The CGMS was 100, 96.1, and 91.0% accurate at normal, high, and low blood glucose concentrations. Measurements deviated from reference by -12.7 +/- 70.5 mg/dL at normal, -12.1 +/- 141.5 mg/dL at high, and -1.9 +/- 40.9 mg/dL at low glucose concentrations. Overall, paired CGMS readings correlated significantly (r = 0.95, P < .0001) and concordance was 95.7%. The median delay after IV administration of glucose to an increase in interstitial glucose was 11.4 minutes (range: 8.8-19.7 minutes). CONCLUSIONS AND CLINICAL IMPORTANCE Although some readings substantially deviated from reference values, the CGMS yields reproducible results, is clinically accurate in cats with hyperglycemia and euglycemia, and is slightly less accurate if blood glucose concentrations are low. Rapidly increasing interstitial glucose after a glycemic rise suggests that the CGMS is suitable for real-time measurement under clinical conditions.

Remission of diabetes mellitus in cats cannot be predicted by the arginine stimulation test

BACKGROUND Cats with diabetes mellitus frequently achieve clinical remission, suggesting residual β-cell function. Responsiveness of β-cells to arginine persists the longest during diabetes progression, making the intravenous arginine stimulation test (IVAST) a useful tool to assess residual insulin and glucagon secretion. HYPOTHESIS Diabetic cats with and without remission will have different arginine-induced insulin or glucagon response. ANIMALS Seventeen cats with diabetes, 7 healthy cats. METHODS Blood samples collected on admission and during subsequent IVAST. Glucose, insulin, and glucagon were measured. Response to IVAST was assessed by calculating the insulin and glucagon area under the curve (AUC) and the AUC glucagon-to-insulin ratio. Diabetic cats were treated with insulin and were followed for 18 weeks. Remission was defined as normoglycemia and disappearance of clinical signs of diabetes for ≥4 weeks, without requiring insulin. RESULTS Seven diabetic cats (41%) achieved remission. On admission, blood glucose concentration was significantly lower in cats with remission (median, 389 mg/dL; range, 342-536 mg/dL) than in those without remission (median, 506 mg/dL; range, 266-738 mg/dL). After IVAST, diabetic cats with remission had higher AUC glucagon-to-insulin ratios (median, 61; range, 34-852) than did cats without remission (median, 26; range, 20-498); glucose, insulin, and glucagon AUCs were not different. Diabetic cats had lower insulin AUC than did healthy cats but comparable glucagon AUC. CONCLUSIONS AND CLINICAL IMPORTANCE Diabetic cats with and without remission have similar arginine-stimulated insulin secretion on admission. Although cats with remission had lower blood glucose concentrations and higher AUC glucagon-to-insulin ratios, large overlap between groups prevents use of these parameters in clinical practice.

Evaluation of four methods used to measure plasma insulin-like growth factor 1 concentrations in healthy cats and cats with diabetes mellitus or other diseases

OBJECTIVE To evaluate 4 methods used to measure plasma insulin-like growth factor (IGF) 1 concentrations in healthy cats and cats with diabetes mellitus or other diseases. ANIMALS 39 healthy cats, 7 cats with diabetes mellitus, and 33 cats with other diseases. PROCEDURES 4 assays preceded by different sample preparation methods were evaluated, including acid chromatography followed by radioimmunoassay (AC-RIA), acid-ethanol extraction followed by immunoradiometry assay (AEE-IRMA), acidification followed by immunochemiluminescence assay (A-ICMA), and IGF-2 excess followed by RIA (IE-RIA). Validation of the methods included determination of precision, accuracy, and recovery. The concentration of IGF-1 was measured with all methods, and results were compared among cat groups. RESULTS The intra-assay coefficient of variation was < 10% for AC-RIA, A-ICMA, and AEE-IRMA and 14% to 22% for IE-RIA. The linearity of dilution was close to 1 for each method. Recovery rates ranged from 69% to 119%. Five healthy cats had IGF-1 concentrations > 1,000 ng/mL with the AEE-IRMA, but < 1,000 ng/mL with the other methods. Compared with healthy cats, hyperthyroid cats had significantly higher concentrations of IGF-1 with the A-ICMA method, but lower concentrations with the IE-RIA method. Cats with lymphoma had lower IGF-1 concentrations than did healthy cats regardless of the method used. CONCLUSIONS AND CLINICAL RELEVANCE Differences in the methodologies of assays for IGF-1 may explain, at least in part, the conflicting results previously reported in diabetic cats. Disorders such as hyperthyroidism and lymphoma affected IGF-1 concentrations, making interpretation of results more difficult if these conditions are present in cats with diabetes mellitus.

Comparison of a continuous glucose monitoring system with a portable blood glucose meter to determine insulin dose in cats with diabetes mellitus

BACKGROUND The continuous glucose monitoring system (CGMS) Guardian REAL-Time(®) allows the generation of very detailed glucose profiles in cats. The performance of CGMS to generate short-term glucose profiles to evaluate treatment response has not been yet evaluated in diabetic cats. HYPOTHESIS Analysis of glucose profiles generated using the CGMS produces insulin dose recommendations that differ from those of profiles generated using the portable blood glucose meter (PBGM) in diabetic cats. ANIMALS Thirteen client-owned diabetic cats. METHODS Prospective, observational study. Simultaneous glucose profiles were generated over an 8-10 hour period using the CGMS, blood glucose concentration was measured every 2 hours with the PBGM. Profiles were submitted to three internal medicine specialists who used them to determine the insulin dose. Differences between insulin doses deduced from paired profiles were compared. Percentages of nadirs recorded with the CGMS that were lower, higher, or equal to those derived with the PBGM were calculated. RESULTS Twenty-one paired glucose profiles were obtained. There was no difference of insulin doses based on CGMS and PBGM profiles (median 0 U; range: -1 to +0.5). Treatment decisions did not differ among investigators. Compared with the observed PBGM nadir, the CGMS nadir was lower, higher, or equal in 17, 2, and 2 of 21 cases, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE Adjustments in insulin dose based on glucose profiles generated with the CGMS are similar to those based on the PBGM. The common occurrence of lower nadirs recorded with the CGMS suggests that this device detects hypoglycemic periods that are not identified with the PBGM.

The dipeptidyl peptidase IV inhibitor NVP-DPP728 reduces plasma glucagon concentration in cats.

Glucagon-like peptide-1 (GLP-1) analogues and inhibitors of its degrading enzyme, dipeptidyl peptidase IV (DPPIV), are interesting therapy options in human diabetics because they increase insulin secretion and reduce postprandial glucagon secretion. Given the similar pathophysiology of human type 2 and feline diabetes mellitus, this study investigated whether the DPPIV inhibitor NVP-DPP728 reduces plasma glucagon levels in cats. Intravenous glucose tolerance tests (ivGTT; 0.5 g/kg glucose after 12 h fasting) and a meal response test (test meal of 50% of average daily food intake, offered after 24 h fasting) were performed in healthy experimental cats. NVP-DPP728 (0.5-2.5 mg/kg i.v. or s.c.) significantly reduced glucagon output in all tests and increased insulin output in the ivGTT. Follow-up studies will investigate the potential usefulness as therapy in diabetic cats.

Diabetes mellitus bei der Katze: Ein Überblick

Etwa 80% der diabetischen Katzen leiden unter einem Typ 2 Diabetes, der durch eine Storung der Freisetzung von Insulin aus den Beta-Zellen und einer Insulin-Resistenz charakterisiert ist. Wie beim Menschen haben auch bei der Katze die veranderten Lebens- und Ernahrungsgewohnheiten zu einer starken Zunahme von Adipositas gefuhrt. Adipositas ist bei beiden Spezies einer der bedeutendsten Risikofaktoren fur die Entstehung eines Typ 2 Diabetes. Die Therapie der Erkrankung sollte unmittelbar nach der Diagnosestellung erfolgen. In Zurich besteht die Therapie aus der zweimal taglichen Gabe eines Intermediarinsulins und aus diatetischen Massnahmen. Der Einsatz von kohlenhydratarmem Futter scheint eine zentrale Bedeutung zu haben. Wir haben die Beobachtung gemacht, dass der Anteil von Katzen mit transientem Diabetesverlauf durch den Einsatz von Diaten mit stark reduziertem Kohlenhydratanteil von ehemals etwa 25% auf 50 bis 70% ansteigt.

Diabetes-Remission bei der Katze: Ein Überblick

Remission from diabetes is seen in 25 - 50 % of cats during the first months of therapy. The likelihood of remission is higher in old cats and cats with normal cholesterol than in young cats and cats with increased cholesterol. The results of an ongoing study indicate that initial intravenous insulin therapy has positive effects on remission rates and quality of metabolic control.