Aim This research aimed to compare 6-month adherence to therapy with exenatide once weekly (Bydureon?) vs liraglutide once daily (Victoza?) in patients with type 2 diabetes under primary care in Germany. Therapy was initiated in 5 449 patients with exenatide once weekly (age: 59.7±11.8 years; 51.4% were male) and Givinostat in 24 648 patients with liraglutide once daily (age: 59.4±11.4 years; 49.7% were male). The median PDC was 0.88 for exenatide once weekly and 0.77 for liraglutide once daily (P<0.05). Once-weekly exenatide was associated with significantly higher adherence. Odds ratio (95% confidence interval) for having a PDC of ≥0.80 was 1.78 (1.62-1.96) for exenatide once weekly compared with liraglutide once daily after adjusting Givinostat for age sex and cotherapy. Conclusion Adherence to treatment with exenatide once weekly was significantly increased compared to that with liraglutide once daily over 6 months in patients with type 2 diabetes. Keywords: type 2 diabetes GLP-1 receptor agonists adherence Introduction Glucagon-like peptide-1 (GLP-1) is an incretin hormone secreted from gastrointestinal cells shortly after an ingested meal.1 2 GLP-1 stimulates insulin secretion in a glucose-dependent manner suppresses glucagon secretion delays gastric emptying and suppresses appetite.1 2 Because of the decreased release and response of incretins in patients with type 2 diabetes the incretin axis is a target for pharmacologic therapy.1 2 The clinical advantages of GLP-1 receptor agonists (GLP-1 RAs) are significant improvements in glycemic control with relevant weight loss and a low risk of hypoglycemia.3 In patients with type 2 diabetes glucose control is highly dependent on adherence to medication regimens and nonadherence has been associated with increased all-cause mortality and all-cause hospitalization.4 The complexity of a dosing regimen is associated with nonadherence. We hypothesized that once-weekly injections of GLP-1 RA may improve patients’ adherence compared with once-daily GLP-1RA therapy. The aim of our study was to compare 6-month adherence to therapy with exenatide once weekly vs liraglutide once daily in patients with type 2 diabetes initiating treatment in primary care in Germany. Methods The longitudinal prescriptions database (LRx) (IMS Health Frankfurt am Main Germany) collects pharmacy data from data centers where the prescriptions of all German patients with statutory health insurance are processed for reimbursement purposes.5 Data entries covered patient-specific Givinostat data over time including the patient’s anonymized identification number age sex insurance company and place of living as well as prescription information including the prescriber’s anonymized identification number prescription date and package information. Information on diagnoses is not part of these data sets. The LRx database currently contain?60% Givinostat of all prescriptions reimbursed nationwide in Germany.5 Considering that exenatide once weekly was launched in Germany in September 2011 (2 years after once-daily liraglutide was available in the German market) the study period for this study was set from January 2011 to September 2014 including a 9-month follow-up period. Patients who initiated GLP-1 RA therapy between January 1 2011 and December 31 2013 (index date) and who had at least 6 months’ follow-up data after the index date were included. Baseline demographic characteristics 6 months before the index date were collected from patients’ records. In Germany no ethics votum is needed for studies based on anonym epidemiological data. The IRB from IMS Health deemed ethical approval and written patient consent were not required as no ethics votum is needed for studies based on anonym epidemiological data. Therapy adherence to exenatide once weekly and liraglutide once daily was measured using the Gsk3b proportion of days covered (PDC) with the index GLP-1RA in the 6-month postindex period. PDC was calculated by taking the total number of days supplied per patient during the postindex 6-month period and dividing that by 180 days. The number of days supplied was calculated as follows: number of entities within a pack × number of.