Substitution of insulin by exenatide in bad controlled type 2 diabetic patients: efficacy and predictive factors

Exenatide therapy is indicated in type 2 diabetes after failure of oral antidiabetic agents (OAD). The aim of this observational prospective study was to assess efficacy of exenatide, in improving HbA1c of at least of 1% (responders) in type 2 diabetic patients treated previously with insulin.

Thirty-six patients (HbA1c >7.5%), with chronic bad glycemic control, were hospitalized to improve glycemia using transient continuous insulin infusion followed by administration of exenatide and OAD agents. In these patients, insulin had been introduced previously because of OAD failure without any sign of severe insulin deficiency.

On the 27 patients analyzed at 3 months, 19 patients were responders (HbA1c: M0: 9.9±1.7%; M3: 7.6±1.2%). Among the 8 non-responders, only 4 deteriorated their HbA1c. After 9 months, 10 patients remained Responders (HbA1c: 7±0.9%). Predictive factors for an improvement of glycemic control were: diabetes duration shorter than 12 years, ratio fasting glycemia/C-peptide less than 1, fasting C-peptide higher than 2.0 µg/L and mean capillary blood glucose after 3 days of exenatide lower than 200 mg/dL. These criteria remained valid in case of a high HbA1c at baseline.

In patients with no signs of insulin dependence and in case of insulin failure, exenatide associated to OAD may be tried in order to improve glycemic control, this objective was reached by 70% of our patients. Predictive factors for good response, easily available in clinical practice, may help therapeutic choices.