Despite an increase in asthma exacerbation rates in New Zealand from 2010 to 2019, exacerbation-related hospitalizations have decreased, according to a recent study published in Respiratory Medicine.
New Zealand is known to have a high rate of asthma prevalence. Researchers there therefore conducted a retrospective, population-based cohort study to examine rates of asthma incidence, exacerbations, and hospitalizations from 2010 to 2019, using data from 5 national health care databases managed by NZ’s Ministry of Health. Exacerbations were identified based on hospital discharge diagnosis codes and oral corticosteroid use.
The researchers calculated asthma exacerbation and hospitalization rates among patients in 5 age categories: less than 5 years old; age 5 to 14 years; age 15 to 44 years; age 45 to 64 years; and age 65 years and older. The researchers also examined how exacerbation and hospitalization rates varied based on patients’ sex, ethnicity, and socio-economic deprivation status (as recorded in the NZ health care data bases).
The total number of patients with asthma increased from 447,797 in 2010 to 512,627 in 2019. Among the 5 age groups studied, asthma was more prevalent among those under the age of 5 years. In that age group, asthma was more prevalent in girls than boys and the prevalence of asthma decreased from approximately 20% in 2010 to 15% in 2019,
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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…
By ethnicity, asthma was more prevalent in indigenous patients who were Maori (with prevalence rates between 12-14% over the 10-year period) and lowest in patients who were Asian. Generally, asthma was more prevalent during the study period among groups considered “most deprived.”
With respect to asthma therapies, the researchers found that more than 80% of patients were using short-acting beta-agonists (SABAs) during the study period. Use of inhaled corticosteroids (ICS) combined with inhaled long-acting beta-adrenoceptor agonists (LABA) increased from 13% in 2010 to 34.5% in 2019.
Overall asthma exacerbation rates increased from 376.2 per 1,000 patient-years in 2010 to 438.3 in 2019. Asthma exacerbation rates were highest in women, increasing from 350 to 400 per 1,000 patient-years in 2010 to just above 450 per 1,000 patient-years in 2019. By age group, the rates were highest in the age group of children under age 5 in 2010, but the rates in this group decreased in 2019, when the highest rates were found in the age group of those 65 year and older. By ethnicity, indigenous patients who were Pacific peoples had the highest exacerbation rates, which remained between 500 to 600 per 1,000 patient-years during the study period. Exacerbation rates throughout the study period were highest among patients categorized as “most deprived.”
Hospital admission rates for asthma decreased by 25% between 2010 and 2019. Acute admissions decreased by 30.3%, from 15.2% of patients in 2010 to 13.7% in 2019. During the study period, 50% of all admission were experienced by indigenous patients who were Maori and Pacific peoples.
Study limitations include the use of discharge and pharmacy data to identify exacerbations and potential inclusion of non-asthma-related exacerbations, especially for individuals age 5 or younger and age 65 or older.
“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,” study authors concluded.
