Biochemical Urine Testing of Medication Adherence and Its Association With Clinical Markers in an Outpatient Population of Type 2 Diabetes Patients: Analysis in the DIAbetes and LifEstyle Cohort Twente (DIALECT)

Abstract

OBJECTIVE To assess adherence to the three main drug classes in real-world patients with type 2 diabetes using biochemical urine testing, and to determine the association of nonadherence with baseline demographics, treatment targets, and complications. RESEARCH DESIGN AND METHODS Analyses were performed of baseline data on 457 patients in the DIAbetes and LifEstyle Cohort Twente (DIALECT) study. Adherence to oral antidiabetics (OADs), antihypertensives, and statins was determined by analyzing baseline urine samples using liquid chromatography–tandem mass spectrometry. Primary outcomes were microvascular and macrovascular complications and treatment targets of LDL cholesterol, HbA1c, and blood pressure. These were assessed cross-sectionally at baseline. RESULTS Overall, 89.3% of patients were identified as adherent. Adherence rates to OADs, antihypertensives, and statins were 95.7%, 92.0%, and 95.5%, respectively. The prevalence of microvascular (81.6% vs. 66.2%; P = 0.029) and macrovascular complications (55.1% vs. 37.0%; P = 0.014) was significantly higher in nonadherent patients. The percentage of patients who reached an LDL cholesterol target of ≤2.5 mmol/L was lower (67.4% vs. 81.1%; P = 0.029) in nonadherent patients. Binary logistic regression indicated that higher BMI, current smoking, elevated serum LDL cholesterol, high HbA1c, presence of diabetic kidney disease, and presence of macrovascular disease were associated with nonadherence. CONCLUSIONS Although medication adherence of real-world type 2 diabetes patients managed in specialist care was relatively high, the prevalence of microvascular and macrovascular complications was significantly higher in nonadherent patients, and treatment targets were reached less frequently. This emphasizes the importance of objective detection and tailored interventions to improve adherence.