ADA 2010: Obesity, poor glycemic control predict which insulin-treated patients will be started on exenatide

In clinical practice, exenatide is often started in patients with type 2 diabetes who are on insulin therapy, even though the prescribing information states that the concurrent use of exenatide with insulin has not been studied and cannot be recommended, according to analysis of a large nationwide database.

Combination of exenatide with insulin was more likely to be started in obese patients with comorbid conditions, found Irl B Hirsch, MD, professor of medicine, division of metabolism, endocrinology and nutrition, University of Washington, Seattle.

"Glycemic control in obese patients with comorbid conditions is difficult to obtain with either drug alone; therefore, despite the absence of clinical evidence to support the combination, it is conceivable that a GLP-1 receptor agonist plus insulin was prescribed due to inability to reach treatment targets while controlling weight gain," according to Hirsch.

Hirsch examined data obtained from the General Electric Centricity research database, which contains approximately 30 million patient records from about 8 million patients in 49 states, including 540,000 persons with type 2 diabetes. The analysis included 7,383 patients who received exenatide and 183,061 who did not.

In a multivariate analysis, a high body mass index (BMI) was the strongest predictor of exenatide initiation, including patients who were on insulin, oral antidiabetic medications, or both. The 9,810 patients who initiated exenatide as their first incretin-based therapy were generally white, younger than 65 years old, heavier than 200 lb, had a glycated hemoglobin level of 7% to 9%, had a blood pressure of at least 130/90 mmHg, lived in the southern or Midwestern regions of the United States, had commercial insurance, and had a creatinine clearance less than 2.

Patients in whom exenatide was initiated while also on insulin therapy were more likely to be heavier than 250 lb, have a BMI greater than 40 kg/m2, have a creatinine clearance less than 2, have a baseline glycated hemoglobin level greater than 9%, and have Medicare as a payer.