Understanding relationships between asthma medication use and outcomes in a SABINA primary care database study

Adherence to inhaled corticosteroids (ICS) in asthma is suboptimal. Patients may rely more on their short-acting beta-agonist (SABA) to control symptoms, which may increase their risk of exacerbations and uncontrolled asthma. Our objective is to describe ICS adherence and SABA use among Dutch primary care patients with asthma, and how these are related to exacerbations and self-reported asthma control. Patients aged ≥12 years diagnosed with asthma who received ≥2 inhalation medication prescriptions in 2016 were selected from the Nivel Primary Care Database. ICS adherence (continuous measure of medication availability), SABA use (number of prescriptions), exacerbations (short courses of oral corticosteroids with daily dose ≥20 mg), and asthma control (self-reported with the Asthma Control Questionnaire; ACQ) were computed. Multilevel logistic regression analyses, to account for clustering of patients within practices, were used to model associations between ICS adherence, SABA use, and asthma outcomes. Prescription data of 13,756 patients were included. ICS adherence averaged 62% (SD: 32.7), 14% of patients received ≥3 SABA prescriptions, and 13% of patients experienced ≥1 exacerbation. Self-reported asthma control was available for 2183 patients of whom 51% reported controlled asthma (ACQ-5 score <0.75). A higher number of SABA prescriptions was associated with a higher risk of exacerbations and uncontrolled asthma, even with high ICS adherence (>90%). ICS adherence was not associated with exacerbations, whilst poor ICS adherence (≤50%) was associated with uncontrolled asthma. In conclusion, increased SABA use is an important and easily identifiable signal for general practitioners to discuss asthma self-management behavior with their patients.