ABSTRACT
OBJECTIVE: The goal of insulin therapy in type 1 diabetes (T1D) is to reduce hemoglobin A1C (A1C) to ≤7.0% (53 mmol/mol) with minimal hypoglycemia. We investigated the possibility that "insulin timing" would improve A1C without incurring severe hypoglycemia in volunteers with T1D over a 6-month observation period. METHODS: Forty healthy adult volunteers with T1D were randomly assigned for 6 months to either a control group or an insulin timing group. The primary endpoint was the difference in A1C between the two groups. As a secondary endpoint, both groups were further divided to assess the importance of the baseline A1C in determining the response to timing. The insulin timing algorithm altered the time when the meal dose of insulin was injected or infused from 30 minutes before the meal to 15 minutes after the meal, depending upon the premeal blood glucose concentration. RESULTS: An improvement in mean A1C was observed in the timing group compared with no change in the control group, but this improvement did not reach statistical significance (P>.05). In contrast, when the two groups were analyzed according to baseline A1C, the timing volunteers with baseline A1C values in the upper half (separated by the A1C median of 7.45% [57.9 mmol/mol]) of the timing group had a more robust response to timing (decline in A1C) than the upper half of the control group (P<.05). CONCLUSION: Insulin timing is a patient-centered translational approach that is safe and effective in improving A1C in individuals with T1D with an elevated A1C. ABBREVIATIONS: A1C = hemoglobin A1C ANOVA = analysis of variance CGM = continuous glucose monitoring CSII = continuous subcutaneous insulin infusion MDI = multiple daily injection T1D = type 1 diabetes.
Subject(s)
Blood Glucose/metabolism , Diabetes Mellitus, Type 1/blood , Diabetes Mellitus, Type 1/drug therapy , Hypoglycemic Agents/administration & dosage , Insulin/administration & dosage , Patient-Centered Care/methods , Adolescent , Adult , Aged , Blood Glucose Self-Monitoring , Drug Administration Schedule , Humans , Hypoglycemia/chemically induced , Hypoglycemia/prevention & control , Hypoglycemic Agents/adverse effects , Insulin/adverse effects , Insulin Infusion Systems/adverse effects , Middle Aged , Young AdultABSTRACT
BACKGROUND: The masked continuous glucose monitoring system (Masked-CGMS) differs from standard CGMSs in three ways: (1) there is no feedback to the user so that no immediate regimen changes can be made; (2) it can only be worn for up to 5 days; and (3) there are no alarms to warn of hyperglycemia or hypoglycemia. Since 2008 masked-CGMS has become popular for identifying reasons that a patient's hemoglobin A1C does not correlate closely with his or her capillary blood glucose measurements. To date only one study addressing the clinical utility of Masked-CGMS for improving A1C in diabetes has been published. No studies are available specifically examining the variability and correlation of Masked-CGMS and A1C. SUBJECTS AND METHODS: We performed 156 Masked-CGMS studies (40 patients studied sequentially a maximum of four times each) in type 1 diabetes patients. We then analyzed the resulting interstitial glucose levels obtained from the Masked-CGMS compared with an A1C measurement performed within 1 week of the Masked-CGMS study. RESULTS: There was a very low correlation between the A1C and the Masked-CGMS-derived mean interstitial glucose level. This statistic did not provide sufficiently predictive information to be clinically useful for changing an individual patient's intensive insulin therapy regimen. CONCLUSIONS: Our data demonstrate that a very weak correlation exists between 5 days of masked CGMS and a concurrently measured A1C level. For the individual type 1 diabetes patient, this relationship would unlikely to be clinically useful in altering the individual's treatment regimen.
