Exenatide is a Glucagon-like Peptide 1 (GLP-1) analogue used to treat Type 2 diabetes mellitus. Its position in the treatment paradigm is unclear and clinical experience has shown variable response. The aim of this study was to review exenatide use in a public outpatient clinic and to find baseline characteristics suitable as predictors of response.
A retrospective audit was performed from March 2011 to March 2013 on all patients who commenced exenatide, and followed for a minimum of six months. Response to exenatide was defined as >1% reduction in HbA1c, in keeping with the National Institute for Health and Care Excellence guidelines1. Logistic regression analysis was used to compare variables associated with response.
90 patients were reviewed, with a mean age 52.0+/- 2.3, weight 101.7+/- 4.2kg, BMI 37.9+/- 2.1, HbA1C 8.9+/- 0.5 %, and diabetes duration of 9.0+/- 1.1 years. 23 were treated with insulin prior to commencing exenatide. At six months, 62 individuals completed 6 months of therapy (68.9%). 11 individuals were lost to follow-up, 8 secondary to poor control, 8 from side effects and 1 due to hypoglycaemia. Of the 62 individuals, 37 were responders. Mean improvements in HbA1C, weight and BMI were -1.1+/- 0.3%, -4.3+/- 1.3kg, and -1.6+/- 0.6 respectively. The only baseline factor associated with a 1% reduction in HbA1c was a greater baseline HbA1C (OR 2.52, CI 1.36 – 4.66, P =0.003). Weight, BMI, age and diabetes duration were not associated with response. At six months, 15 of 23 patients who started exenatide with insulin remained on exenatide and 13 had ceased insulin with mean reduction in insulin dose of 47.5 units.
A higher HbA1c at baseline was the only significant factor predicting HbA1C improvement. Exenatide is an important therapy in the diabetes armament but response seems idiosyncratic and remains difficult to predict with baseline variables.