OBJECTIVES: To describe persistence patterns to OHM in newly treated Irish patients with T2DM. The study also investigated the effect of age, gender, reimbursement scheme and type of OHM on persistence. METHODS: A population based retrospective cohort study was conducted using national pharmacy claims databases, including two community drugs schemes; Long Term Illness, (LTI, non-means tested) and General Medical Services (GMS, means tested). Newly treated T2DM patients were identified for 2008-2009, having received no OHM in the previous year, and followed up until Nov-2012. Patients who subsequently switched or received additional OHM were excluded. Non-persistence was defined as a prescription gap of >12 weeks and within 1 year of initiating treatment. Logistic regression examined associations of age, gender, scheme and type of OHM with persistence with results presented as odds ratios (OR) and 95% confidence intervals (CI). RESULTS: 15,174 were eligible for the study. Most patients were initiated on metformin (79.4%) and sulphonylureas (19.1%). Persistence at 1 year was 60.9%. The median overall time to non-persistence was 51.5 days. Men were slightly more likely to be persistent than women (OR=1.08; 95%CI=1.001 to1.15; p=0.0025). Patients aged 16-44 and 75+ were less likely to be persistent than patients aged 55-64 (OR= 0.18; 95%CI=0.16-0.21; p<0.0001 and OR=0.67; 95%CI=0.60-0.75; p<0.0001 respectively). Patients registered with the LTI Scheme were more likely to be persistent than from the GMS Scheme (OR=1.35; 95%CI=1.20-1.51; p<0.0001). Patients initiated on sulphonylureas were less likely to be persistent than those initiated on metformin (OR=0.50; 95%CI=0.45 to 0.54; p<.0001). CONCLUSIONS: Persistence amongst newly treated T2DM patients appears to be low. Type of OHM, age and scheme were all significantly associated with persistence. Prescribers should pay particular attention to newly treated patients covered under the GMS scheme, at the extremes of age and those initiated on sulphonylureas.