Therapeutic adherence and associated factors among high-risk patients with type 2 diabetes in primary healthcare: a cross-sectional study using real-world data from the Madrid Region.

Background: Therapeutic adherence is a key component of chronic disease management, particularly in high-risk patients. Type 2 diabetes (T2DM) is common in this population; however, real-world evidence on therapeutic adherence and the factors associated with it among high-risk patients with T2DM remains limited in Spain and other regions. Objective: To evaluate therapeutic adherence and identify factors associated with nonadherence among high-risk patients with T2DM using real-world primary care data. Materials and methods: A cross-sectional study was conducted among adults with T2DM classified as high-risk chronic patients using primary healthcare electronic health records from the Madrid Region as of 30 April 2021. Sociodemographic, functional, clinical, lifestyle, pharmacological, and primary healthcare utilization variables were analyzed according to therapeutic adherence status. Multivariable logistic regression was performed to identify factors independently associated with therapeutic nonadherence. Results: Among 67,746 high-risk patients with T2DM, adherence information was available for 65,856 patients, of whom 45,669 (69.3%) were classified as nonadherent. Nonadherent patients had a higher prevalence of polypharmacy (62.1% vs. 58.7%) and greater healthcare utilization, with a higher mean number of primary care contacts during the first year (25.3 vs. 24.4). In the multivariable analysis, the independent factors associated with higher odds of nonadherence were older age (odds ratio (OR = 1.008), male sex (OR = 1.073), foreign status (OR = 1.157), Individual Health Card category 3 (annual income up to €18,000) (OR = 1.245), ischaemic heart disease (OR = 1.137), heart failure (OR = 1.072), COPD (OR = 1.571), asthma (OR = 1.622), depression (OR = 1.054), palliative care (OR = 1.352), smoking status (OR = 1.102), polypharmacy (OR = 1.345), and ≥20 primary care contacts (OR = 1.066). Conclusions: Therapeutic nonadherence is highly prevalent among high-risk patients with T2DM managed in routine primary care. Nonadherence was independently associated with treatment burden, specific patterns of clinical complexity, behavioral factors, and healthcare needs, with some associations showing modest effect sizes, highlighting the multifactorial nature of therapeutic adherence in this population. These findings support the integration of routine adherence assessment and individualized medication management strategies into primary care for patients with complex chronic conditions.