Asthma exacerbations in New Zealand 2010-2019: A national population-based study

Asthma is one of the most common long-term conditions in the world, with New Zealand (NZ) having one of the highest rates of asthma symptoms. Despite the significant burden of asthma in NZ, there is a lack of data on asthma exacerbation rates in NZ and how these have varied over time. This study is a national population-based study of asthma exacerbation rates in NZ between 2010 and 2019, and explores how these rates vary amongst different demographic groups.

A retrospective population-based observational cohort study covering the ten years 2010-2019 to determine asthma prevalence, and asthma exacerbation and hospitalisation rates, using de-identified data from five national healthcare datasets. Exacerbations were defined based on hospital discharge diagnoses or oral corticosteroid dispensing.

Total number of patients with asthma was 447,797 in 2010 to 512,627 in 2019, equating to approximately 10% of the population. Of these 19.4% experienced an exacerbation in 2010 (a population rate of 376.2 per 1000 patient-years); this exacerbation rate increased to 25.1% in 2019 (438.3 per 1000 patient-years). Exacerbations rates were consistently higher for females than males, and among Pacific peoples and Māori. In contrast, hospital admissions 25% lower in 2019 than 2010, decreasing from 1.4% to 0.9%, however over 50% of these admissions were in Māori and Pacific peoples.

Asthma exacerbation rates in NZ have increased over 2010-2019, however hospitalisation rates have decreased. This potentially suggests a move away from secondary to primary care management of exacerbations and provides important information for asthma care planning.