Subcutaneous continuous glucose monitoring and dose adjustment decreases glycosylated hemoglobin in spontaneously diabetic cynomolgus monkeys.

Spontaneously diabetic cynomolgus monkeys (Macaca fascicularis) exhibit a condition similar to human type 2 diabetes. These monkeys have been maintained by treatment with insulin therapy based on fasting blood glucose levels and glycosylated hemoglobin (HbA1c) values, which are determined periodically by blood sampling. Instead we sought to determine whether the MiniMed Continuous Glucose Monitoring System (CGMS, MiniMed Inc., Sylmer, Calif.), which takes glucose measurements continually over 24 h, would facilitate monitoring and treatment in diabetic cynomolgus monkeys. We attached the CGMS to five diabetic monkeys and obtained their blood glucose profiles. The performance of the CGMS was evaluated against blood glucose values obtained using a palm-sized blood glucose meter. The CGMS accurately measured the animals' blood glucose levels, with a median correlation of 0.95 and a mean absolute difference of 8.2% +/- 4.7% in comparison to the hand-held blood glucose meter. The diabetic monkeys were monitored two or three times during the 3-month study period. Throughout the study, the feeding time, dosage, and insulin administration time were changed in three of the five monkeys in light of the monitoring results. HbA1c levels were measured before and at 1 and 3 months after insulin adjustment. Although the adjusted dosage was not significantly different from the preceding one, HbA1c levels decreased from 7.6% +/- 1.3% to 6.5% +/- 1.1% (P < 0.05) by the end of the study. We concluded that the values from the CGMS closely correlated with those obtained with the hand-held blood glucose meter. Using the CGMS to determine blood glucose profiles allows the blood glucose levels of the monkeys to be monitored during the night as well as the day. Therefore, such continuous monitoring is useful in preventing nocturnal hypoglycemia and hypoglycemic seizures and may facilitate successful management of diabetes.