The Flexible Insulin Therapy (FIT) is a method of therapeutic education with the aim of improving the glycemic control and relieved the constraints related to diabetes in patients with type 1 (T1D) by adapting insulin therapy to their lifestyle. The purpose of this prospective study was to demonstrate the importance of the fasting test in adjusting the dose of basal insulin and to detect other causes of glycemic variability. The patients underwent a no-carbohydrate fasting test. We compared the dose of basal insulin before and after the fasting test. We checked for a dawn phenomenon, ahyperglycemia escape effect, insulin sensitivity and for the right dose of carbohydrates ingestion needed to correct the hypoglycemia. The study included 83 patients aged of 25.2 years on average. Most of these patients were imbalanced with an average HbA1c of 8.9%. The basal dose was on average lower after the FIT vs before. The fasting test showed a basal insulin overdose in 81% of patients. This test revealed a phenomenon of dawn in 53% of patients and a hyperglycemia escape effect in 22% of cases. Our results showed the main role of the fasting test in the determination of the appropriate basal insulin dose. Hyperglycemia escape effect or/and a dawn phenomenon may explain the glycemic imbalance in some patients. This test was very important for assessing insulin sensitivity, for adaptation the carbohydrate ingestions dose to correct hypoglycemia and consequently allowing the patients, a better management of theirs blood sugar levels in real life.
