Comparative Adherence and Persistence of Single- and Multiple-Inhaler Triple Therapies Among Patients with Chronic Obstructive Pulmonary Disease in an English Real-World Primary Care Setting

Purpose: Triple therapy comprising a long-acting muscarinic antagonist, long-acting β₂-agonist and inhaled corticosteroid is recommended for patients with chronic obstructive pulmonary disease (COPD) who continue to experience frequent exacerbations or symptoms whilst receiving dual therapy. Adherence and persistence to multiple-inhaler triple therapy (MITT) is known to be poor. This study assessed comparative adherence to single-inhaler triple therapy (SITT) versus MITT in a real-world setting in England.

Patients and methods: This was a retrospective cohort study using linked primary care (Clinical Practice Research Datalink Aurum) and secondary care (Hospital Episode Statistics [HES] Admitted Patient Care) data to identify patients with COPD who were newly initiated on SITT or MITT between November 2017 and June 2019. Eligible patients were aged ≥35 years and had a forced expiratory volume in 1 second/forced vital capacity <0.7, linkage to HES and continuous registration with a general practitioner for 12 months pre- and 6 months post-initiation. Inverse probability of treatment weighting was used to balance baseline characteristics between cohorts. Adherence was measured using the proportion of days covered by days' supply of SITT or MITT prescriptions. Persistence was measured with a gap of >30 days between the end of a prescription and the following refill used to determine non-persistence.

Results: Overall, 4080 SITT and 6579 MITT users comprised the study cohort. After weighting, the baseline characteristics between the cohorts were comparable (absolute standardized mean difference <10%). SITT users had significantly higher adherence than MITT users at 6, 12, and 18 months post-initiation (p<0.001 for all comparisons). Median persistence was higher among SITT users than MITT users (5.09 months vs 0.99 months).

Conclusion: Patients with COPD in England initiating SITT had significantly better adherence and persistence compared with MITT initiators. These improvements continued at least 18 months following treatment initiation.