[Characterization of and costs associated to the profile of patients with type 2 diabetes treated with metformin who are added a second oral antidiabetic drug: a population study].
OBJECTIVES
To determine compliance, metabolic control, complications and healthcare costs of patients treated with metformin started a second antidiabetic drug in patients with type 2 diabetes (T2DM).


PATIENTS AND METHODS
Design multicenter observational retrospective. Patients were evaluated ≥30 years (age), treated with metformin and started a second antidiabetic treatment during 2008-2009. There were 4 patient groups (metformin and another antidiabetic): a) dipeptidyl peptidase-4 inhibitors (IDPP4), b) sulfonylureas, c) glitazones and d) insulin.


MAIN MEASURES
comorbidity, metabolic control, compliance and complications. Patients were followed for 2 years. The cost model differed direct health costs (primary care / specialist) and indirect (labor productivity).


STATISTICAL ANALYSIS
logistic regression models and ANCOVA, p<0.05.


RESULTS
2067 patients were included (mean age: 66.6 years male: 53.1%). 25.1% started a second treatment with IDPP4; 42.9% sulfonylureas, 14.0% glitazones and 18.0% insulin. At 2 years follow-up, patients treated with IDPP4 showed greater adherence vs. 70.3%. 59.9%, 60.3% and 58.4; better control of 64.3% vs. DM2. 62.6%, 62.8% and 50.5% and a decrease of 13.9% compared to hypoglycaemia 40.4%, 37.6% and 58.9% respectively (p<0.001). The average / unit total costs was €2,321 vs. €2,475, €2,724 and €3,164, respectively, p<0.001. Rates of cardiovascular events and renal failure were 3.7%, 6.4%, 7.6% and 10.2% respectively.


CONCLUSIONS
Sulfonylureas were the most commonly used drugs. Patients treated with IDPP4 had higher compliance and control of diabetes, with lower rates of hypoglycaemia and healthcare costs.