Evaluation of a continuous glucose monitoring system in cats with diabetes mellitus.
ABSTRACT A continuous glucose monitoring system (CGMS) was evaluated in 14 cats with naturally occurring diabetes mellitus. The device measures interstitial fluid glucose continuously, by means of a sensor placed in the subcutaneous tissue. All cats tolerated the device well and a trace was obtained on 15/16 occasions. There was good correlation between the CGMS values and blood glucose concentration measured using a glucometer (r=0.932, P<0.01). Limitations to the use of the CGMS are its working glucose range of 2.2-22.2 mmol/l (40-400 mg/dl) and the need for calibration with a blood glucose measurement at least every 12 h. When compared to a traditional blood glucose curve, the CGMS is minimally invasive, reduces the number of venepunctures necessary to assess the kinetics of insulin therapy in a patient and provides a truly continuous glucose curve.
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ABSTRACT: The MiniMed Continuous Glucose Monitoring System (CGMS) measures subcutaneous interstitial glucose levels that are calibrated against three or more fingerstick glucose levels daily. The objective of the present study was to examine whether the relationship between plasma and interstitial fluid glucose is altered by changes in plasma glucose and insulin levels and how such alterations might influence CGMS performance. Arterialized plasma glucose, sensor glucose, and interstitial fluid glucose were measured by microdialysis in 11 healthy subjects during a 1.0 mU. kg(-1). min(-1) stepped euglycemic-hypoglycemic-hyperglycemic (plasma glucose approximately 5, 3.1, and 8.6 mmol/l, respectively) insulin clamp that raised plasma insulin to approximately 360-390 pmol/l. When the CGMS was calibrated versus plasma glucose levels before insulin infusion, basal sensor and plasma glucose were similar (5.0 +/- 0.3 vs. 5.2 +/- 0.3 mmol/l, respectively); dialysate glucose was 3.3 +/- 0.9 mmol/l. During the hyperinsulinemic-euglycemia study (plasma glucose 4.9 +/- 0.3 mmol/l), dialysate glucose fell by 30-35%, accompanied by a significant reduction in sensor glucose (to 3.7 +/- 0.6 mmol/l; P < 0.001 vs. plasma). Subsequently, sensor levels remained lower than plasma values during mild hypoglycemia (2.5 +/- 0.6 vs. 3.1 +/- 0.3 mmol/l; P < 0.01) and during recovery from hypoglycemia (7.3 +/- 1.2 vs. 8.6 +/- 0.6; P < 0.01). However, when the CGMS was calibrated against plasma glucose levels before and during each step of the clamp, sensor glucose levels increased throughout the study and did not differ from plasma glucose values during hypoglycemia. Although hyperinsulinemia may contribute to modest discrepancies between plasma and sensor glucose levels, the CGMS is able to accurately track acute changes in plasma glucose when calibrated across a range of plasma glucose and insulin levels.Diabetes Care 05/2002; 25(5):889-93. · 7.74 Impact Factor
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ABSTRACT: Medical records of 104 cats with diabetes mellitus were reviewed. Information from 54 cats that had multiple blood glucose concentrations evaluated at least 5 times over a minimum of 3 months, beginning at the time insulin treatment was initiated, was used to evaluate the efficacy of insulin in treating diabetes mellitus. Fourteen of 54 cats were treated with protamine zinc insulin (PZI), 26 with ultralente insulin, and 14 with lente insulin. Six, 29, and 19 cats had good, mediocre, and poor glycemic control, respectively, based on mean blood glucose concentrations, whereas 31, 21, and 2 owners thought clinical response was good, mediocre, and poor, respectively. No significant difference was found in glycemic control among cats treated with PZI, ultralente, or lente insulin. Glycemic control was significantly (P < .05) better in 33 cats without than in 21 cats with concurrent disease. All 104 cats were used to calculate survival data. Fifty-one of 104 cats were alive at the time of the study. Mean (+/- standard deviation [SD]) and median survival times were 24 (+/- 16) and 20 months, respectively, in the 51 cats still alive at the end of the evaluation, and 25 (+/- 4) and 17 months, respectively, in the 53 cats that had died during the period of evaluation. Pancreatic abnormalities identified in 37 cats that underwent necropsy included chronic pancreatitis (n = 17), acute to subacute pancreatitis (n = 2), exocrine pancreatic adenocarcinoma (n = 7) and adenoma (n = 1), islet cell atrophy and vacuolar degeneration (n = 27), and islet amyloidosis (n = 8). No association was found between glycemic control and islet amyloidosis or exocrine pancreatic neoplasia, or between survival time and chronic pancreatitis, islet amyloidosis, or exocrine pancreatic neoplasia. In conclusion, diabetic cats evaluated in this study showed a variable response to exogenously administered insulin, ranging from excellent to poor. By maintaining mean blood glucose concentrations under 300 mg/dL, clinical signs were improved, and owners were satisfied with insulin treatment. Concurrent potentially insulin-antagonistic diseases were common and deleteriously affected glycemic control and survival time.Journal of Veterinary Internal Medicine 01/1998; 12(1):1-6. · 2.06 Impact Factor
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ABSTRACT: To evaluate the reliability of history and physical examination findings for assessing control of glycemia in insulin-treated diabetic dogs. Retrospective study. 53 insulin-treated dogs with diabetes mellitus. Medical records of insulin-treated diabetic dogs from June 1995 to June 1998 were reviewed, and information on owner perception of their dog's response to insulin treatment, physical examination findings, body weight, insulin dosage, and concentrations of food-withheld (i.e., fasting) blood glucose (FBG), mean blood glucose (MBG) during an 8-hour period, blood glycosylated hemoglobin (GHb), and serum fructosamine was obtained. Owner's perception of their dog's response to insulin treatment, physical examination findings, and changes in body weight were used to classify control of glycemia as good or poor for each dog. The FBG, MBG/8 h, blood GHb, and serum fructosamine concentrations were compared between well-controlled and poorly controlled insulin-treated diabetic dogs. Presence or absence of polyuria, polydipsia, polyphagia, lethargy, and weakness were most helpful in classifying control of glycemia. Mean FBG and MBG/8 h concentrations, blood GHb concentrations, and serum fructosamine concentrations were significantly decreased in 25 well-controlled diabetic dogs, compared with 28 poorly controlled diabetic dogs. Most well-controlled diabetic dogs had concentrations of FBG between 100 and 300 mg/dl, MBG/8 h < or = 250 mg/dl, blood GHb < or = 7.5%, and serum fructosamine < or = 525 mumol/L, whereas most poorly controlled diabetic dogs had results that were greater than these values. Reliance on history, physical examination findings, and changes in body weight are effective for initially assessing control of glycemia in insulin-treated diabetic dogs.Journal of the American Veterinary Medical Association 08/2000; 217(1):48-53. · 1.72 Impact Factor