Predictors of suboptimal glycaemic control in type 2 diabetes patients: The role of medication adherence and body mass index in the relationship between glycaemia and age

AimsTo analyse predictors of glycaemic control including medication adherence and body mass index (BMI) in UK general practice patients with sub-optimally controlled type 2 diabetes.MethodsBaseline demographic, health- and treatment-related measures were evaluated as predictors of one year glycaemic control defined separately as HbA1c ≤ 7.5% and a continuous measure of HbA1c concentration, using multivariate regression models. Significant predictors were adjusted for objectively assessed medication adherence and BMI.ResultsOne-year HbA1c concentration was associated with baseline HbA1c (p < 0.001), BMI (p = 0.02), and inversely associated with age (p = 0.007) and objectively assessed adherence. Adherent patients had one-year (adjusted) HbA1c concentration 0.65% (95% CI −1.04, −0.25; p = 0.001) lower than nonadherent. Odds ratios (95% CI) of HbA1c ≤ 7.5% for 10-year higher age were 1.63 (1.08, 2.45); for adherent compared to non-adherent patients 1.89 (0.84, 4.25); for patients receiving >5 compared to ≤5 medications 0.32 (0.13, 0.76); and for each 1% increment in baseline HbA1c 0.48 (0.31, 0.73).ConclusionsThe lower HbA1c achieved from greater adherence to glucose lowering treatment is comparable to that achieved with additional medication. Relationships between older age and better glycaemic control are not explained by better adherence, but may partly relate to lower BMI.