Long-acting bronchodilator use in chronic obstructive pulmonary disease in primary care in new zealand: A retrospective study of treatment patterns and evolution using the healthstat database

Abstract

Purpose: Long-acting bronchodilator (LABD) use is the mainstay of pharmacologic treatment for chronic obstructive pulmonary disease (COPD). Few studies describe evolving patterns of LABD use in the setting of changing inhaler availability and updated clinical guidelines. Methods: A retrospective cohort study in New Zealand using the HealthStat general practice database (01/2014 to 04/2018). Eligible patients (aged ≥40 years) had COPD and ≥1 LABD prescription (long-acting muscarinic antagonist [LAMA] and/or long-acting β2-agonist [LABA]) during the index period (05/2015 to 04/2016). Demographics and clinical characteristics of all LABD users (overall/by treatment) were described at baseline. Patients starting LABD treatment during the index period, termed “new” users, were also described, as was their treatment evolution over 24 months of follow-up. Yearly LABD initiation rates were assessed from 2015 to 2017, covering changes to Pharmaceutical Management Agency criteria and clinical guidelines. Results: Across 2140 eligible patients, the most common index treatments were inhaled corticosteroid (ICS)/LABA (59.0%) and open triple therapy (LAMA+LABA+ICS; 26.7%). ICS/LABA therapy was highest in younger patients, with open triple therapy highest in older patients. Prior yearly exacerbation rates were lowest in those receiving monotherapy (LABA: 0.9/year; LAMA: 1.1/year) versus dual therapy (all 1.4/year) and open triple therapy (2.2/year). Of 312 new LABD users, ICS/LABA was the most common index treatment (69.6%), followed by LAMA monotherapy (16.0%). Continuous use with index treatment was 31.1% at 12 months and 13.5% at 24 months; mean time to treatment change was 175.5 and 244.1 days, respectively. Among patients modifying treatment at 24 months, 23.0% augmented, 7.0% switched, 45.6% re-started, and 24.4% discontinued/stepped down. Among patients initiating LABD each year from 2015 to 2017, LAMA prescription increased (17% to 46%) while ICS prescription remained stable (approximately 20%). Conclusion: Predominant use of ICS/LABA (05/2015 to 04/2016) reflects available LABDs and previous restrictions on LAMA use in New Zealand.