Improving Therapeutic Adherence of Oral Antidiabetics in Insulin-Dependent Patients with Type 2 Diabetes Mellitus: the Combination of a Fixed-Dose

Abstract

Objective: To assess whether the combination of fixed-dose Oral Antidiabetic drugs (OA) in a single tablet compared to OA separated into 2 or more tablets is an effective strategy to improve adherence in insulin-dependent patients with Type 2 Diabetes Mellitus (DM2). Methods: This was a prospective, longitudinal, multi-center study, carried out in 3 primary care centers in Spain. One hundred and twenty patients treated with OA and insulin prescribed for insulin-dependent DM2 were included. A cluster randomization was performed based on two groups: (1) Control Group (CG): Sixty patients treated with two OA prescribed separately in different tablets, and (2) an Intervention Group (IG): Sixty patients treated with OA were with 2 drugs in combination at a fixed dose, in a single tablet. Three visits took place. AO Adherence was measured by using electronic monitors (MEMS). Average adherence percentage (%; Average AP) and daily compliance (%; Daily AP) was calculated. A patient was considered adherent when AP was 80–100%. Insulin adherence was measured by counting. Results: One hundred and ten patients completed the study (79 in the IG and 31 in the CG). Global adherence was 92,59% and 79,62% in IG and 82,85% and 48,21% in CG at 6 and 12 months, respectively (p<0.05 by groups). Daily adherence was 79,62% and 62,96% in IG and 17,85% and 10,71% in CG at 6 and 12 months, respectively (p<0.05). Global adherence with insulin by count was 77,78% and 70,37% in IG and 57,14% and 60,71% in CG at 6 and 12 months, respectively with significant differences. In the non-adherent group, the number of concomitant medications and glucemia and haemoglobin A glycosylate levels at 6 and 12 months, were significantly higher than in the adherent population. The NNT was 4,42 patients to prevent one non-adherence. Conclusions: The combination of fixed-dose OA in a single tablet compared to OA separated into 2 or more tablets is an effective strategy to improve AO therapeutic adherence in patients with insulin-dependent DM2.