Background The rise in obesity is leading to an increasing rate of type 2 diabetes in those aged younger than 40. Management of hyperglycaemia and cardiovascular disease (CVD) in this age profile is complicated by higher insulin requirements and contraindications to certain CVD agents, yet few studies to date have focussed on the primary care setting. The aims of this study were to: 1) characterise antidiabetic drug utilisation including non-persistence, treatment addition and switching, 2) investigate factors associated with insulin use, 3) characterise the use of and factors associated with CVD agents in early onset diabetes.

Methods A population-based retrospective cohort study from 2008–2011 was conducted using the Irish national pharmacy claims database. Subjects aged 15–39 were analysed for use of antidiabetic therapy and any co-prescription of cardiovascular agents. Cox proportional-hazards regression and logistic regression were used to examine associations of socio-demographic and treatment factors on treatment patterns, including non-persistence (among males), initiation of insulin and use of cardiovascular agents. Hazard ratios (HR), odds ratios (OR) and 95% confidence intervals (CI) are presented.

Results From 2008–2011 there were 5284 individuals initiated on antidiabetic agents. Most were initiated on metformin (88%) and 26% of those with a treatment addition or switching received insulin. A total of 62% of males were persistent with their initial antidiabetic agent. Over 40% of subjects were initiated on cardiovascular agents. The likelihood of non-persistence was significantly higher in males aged 15–29 years (HR 1.97 [CI 1.58–2.45]) and those on sulphonylureas (HR 1.79 [CI 1.35–2.37]). Females and those aged 15–29 years were more likely to receive insulin (HR 1.61[CI 1.19–2.19] and HR 1.51 [CI 1.10–2.09] respectively), and less likely to receive cardiovascular agents (HR 0.50 [CI 0.42–0.83] and HR 0.46 [CI 0.37–0.57] respectively).

Conclusion Early onset type 2 diabetes has been shown to be a complex condition associated with high levels of treatment non-persistence, use of insulin and of CVD agents in certain sub-groups. Treatment patterns differ between those aged 15–29 years compared to those aged 30–39 years as well as by gender. The choice of initial agent affects future treatment use and prescribers should thoroughly assess the suitability of a sulphonylurea as the initial agent. Given that diabetes is a chronic, progressive condition that is increasingly occurring in younger populations, it is essential that health professionals and policy makers address the selection of, and persistence with medicines in each of the sub-groups identified in this study.