The Relationship Between Glucose-Lowering Medications, Adherence, and Outcomes in Patients with Type 2 Diabetes.

Adherent type 2 diabetes (T2DM) patients are more likely to have good glycaemic control than non-adherent patients, potentially resulting in better outcomes. We investigated the association between the number of glucose-lowering therapies, adherence and their impact on glycaemic control and quality of life (QoL). Data were drawn from the 2013 Diabetes Disease Specific Programme, a large cross-sectional real-world survey of primary care physicians (PCP) and specialists and their patients consulting for diabetes. Physicians provided information regarding prescriptions, previous treatment and most recent HbA1cvalues. Patients completed the Morisky Measurement of Adherence Scale and the EQ-5D. Patients who had been on current treatment between 6 months and 5 years and had values for all variables were included. A linear Structural Equation Model was developed to explore the relationships between the number of oral and injectable diabetes medications per day, adherence, glycaemic control and QoL while adjusting for confounding factors relating to duration and type of medication, existing complications, concomitant conditions, demographic and lifestyle factors. 239 PCPs and 137 specialists across 5 EU countries provided data on 1209 T2DM patients. 58% patients were male, mean age 60.7 years (+/-10.3); number of oral medications 2.21 (+/-1.16); injectables 0.36 (+/-1.03); current HbA1c6.94% (+/-0.80). The model shows that a lower number of daily diabetes medications is positively associated with adherence [orals (β=-0.10, p<0.001), injectables (β=-0.049, p<0.001)]. Improved adherence is associated with a lower HbA1c (β=-0.10, p<0.001), lower HbA1cis associated with improved QoL (β=-0.019, p<0.001). Controlling for important clinical and demographic factors, a lower number of daily glucose-lowering therapies is associated with greater adherence which, in turn, is associated with better glycaemic control and improved QoL. Further research is required to investigate if these associations vary depending on the specific medication taken or other patient-related parameters not considered here.