Guideline-conformity of initiation with oral hypoglycemic treatment for patients with newly therapy-dependent type 2 diabetes mellitus in Austria

Abstract

Purpose: To determine guideline conformity of initiation of oral hypoglycemic (OH) treatment for type 2 diabetes in Austria; to study patient and prescriber correlates of recommended initiation with metformin monotherapy.

Methods: We used claims from 11 sickness funds that covered 7.5 million individuals, representing >90% of the Austrian population. First-time OH use was defined as a first filled prescription after one year without any OH drug or insulin. Among these incident users, we described the OH drug class used and defined correlates of initiation with metformin monotherapy.

Results: From 1/2007 to 6/2008, we identified 42,882 incident users of an OH drug: 70.8% used metformin, 24.7% used a sulfonylurea, and 4.5% initiated treatment with another class. We estimated the incidence of OH-dependent type 2 diabetes at 3.8-4.4 per 1000 patient-years. We conducted multivariate analyses among 39 077 patients with available prescriber information. Independent correlates of initiation with metformin were younger age, female gender, waived co-payment, more recent initiation, fewer hospital days and more therapeutic classes received in the year prior to first OH therapy (all p < 0.001). Prescriber specialty and age (p < 0.001), but not gender, were also associated with metformin initiation. Approximately 20% of metformin initiators had a second OH drug added within <18 months. While we were unable to ascertain specific contraindications to metformin (renal insufficiency, hepatic failure), <10% of the general population are expected to have these conditions.

Conclusions: Seventy per cent of new initiators of OH treatment in Austria received metformin as recommended by international guidelines. At least 20% did not, taking into account possible contraindications, which provides an opportunity for intervention.