BACKGROUND: The effectiveness of a drug is significantly influenced by a patient's adherence to the required regimen.
OBJECTIVE: The goal of this retrospective database analysis was to determine the factors affecting adherence over a 12-month follow-up period in adults with type 2 diabetes mellitus (DM) initiating once-daily liraglutide (1.8 mg) or twice-daily exenatide (10 μg).
METHODS: A patient-centric claims database was used, covering the period January 2009 to December 2011. Patients were included if they had ≥1 claim of once-daily liraglutide 1.8 mg or twice-daily exenatide 10 μg from January to December 2010 (index date [ID]), ≥2 diagnoses of type 2 DM before ID, continuous enrollment for 12 months before and after ID, and age ≥18 years at ID. Patients were required to be glucagon-like peptide-1 receptor agonist treatment-naive in the 12 months preceding ID and have a second prescription for once-daily liraglutide 1.8 mg or twice-daily exenatide 10 μg during the 12 months after ID. The medication possession ratio (MPR) was used as a continuous variable and to categorize patients as high-adherent (MPR ≥80%) or low-adherent (MPR <80%). Regression analyses were conducted to determine the predictors for nonadherence in the type 2 DM population, with bivariate testing of the MPR categories conducted initially to determine the predictors to be included in the final regression model.
RESULTS: A total of 3623 patients (once-daily liraglutide 1.8 mg, n = 2036; twice-daily exenatide 10 μg, n = 1587) were identified. Variables found to reduce adherence were younger age, female sex, Southern geographic region, twice-daily exenatide treatment, and higher percentage of copayment from the claimant. After adjusting for confounding factors, patients receiving once-daily liraglutide 1.8 mg were ∼11% more adherent than patients receiving twice-daily exenatide 10 μg (95% CI, 7-14; P < 0.0001). The odds ratio for "poor" adherence (MPR <80%) with twice-daily exenatide 10 μg therapy compared with liraglutide 1.8 mg once-daily was 1.33 (95% CI, 1.16-1.53; P < 0.0001).
CONCLUSIONS: This study found that adherence to once-daily liraglutide 1.8 mg treatment was superior to twice-daily exenatide 10 μg over a 12-month follow-up period. Nonadherence has important implications to the health care system, both in terms of clinical effectiveness and economic burden (eg, hospitalization, productivity losses). Using strategies to increase adherence is vital to reduce the future clinical and economic burden of diabetes.
