Asthma

Key messages

• Admission rates in young children aged 0–4 years are significantly higher than in children aged 5–11 years and adults aged 12 years or over. 
• Admission rates for Pacific peoples and Māori are significantly higher than rates for European/Asian/other across all age groups.
• Overall, the rate of admissions for adults aged 12 years and over has declined from 0.9 per 1,000 in 2018 to 0.8 per 1,000 in 2023 — a reduction of approximately 300 people admitted.
• Thirteen percent of people admitted had a second admission within three months of discharge, and 15 percent had a second admission within three to twelve months.
• More than one-third (34 percent) of people admitted with asthma were not regularly dispensed an inhaled corticosteroid (ICS) in the year following their admission. There was limited variation between districts.
• Eighty-one percent of people admitted did not receive a funded influenza vaccine in the year after their admission, with the highest rates among those under 45 years of age.
• In the community, among people regularly dispensed a short-acting beta agonist (SABA), 20 percent were not dispensed any preventer medication in the same year, and 31 percent were not regularly dispensed a preventer medication.
• Relative to other asthma inhalers, dispensing of combined budesonide + formoterol inhalers in the calendar year has increased significantly from 15 percent in 2018 to 50 percent in 2023.

Key findings

Pacific and Māori children were more likely to be admitted than European/Asian/other

• In 2023, more than 7 per 1,000 children (~5,548) aged 0–11 years were admitted one or more times with a primary diagnosis of asthma each year.

• Rates varied four-fold between districts, ranging from 3.1 to 12.6 per 1,000.

• Pacific children had the highest admission rate (13.8/1,000) followed by Māori (9.8/1,000) and then European/Asian/Other children (6.0/1,000).

• Younger children aged 0–4 years had the highest rate of admission at about 13.1 per 1,000 children.

• Boys aged 0–4 years (15.7 per 1,000) were significantly more likely to be admitted than girls (10.3 per 1,000).

Pacific and Māori adults were more than three times more likely to be admitted with asthma than European/Asian/other

• On average 0.8 per 1,000 adults (~3100) aged 12 years or over were admitted one or more times in a year with a primary diagnosis of asthma each year.
• In 2023, adult asthma admissions varied four-fold by district, from 0.4 to 1.2 per 1,000 people aged 12 years and over.
• Admissions decreased during the 2020-2021 period for all ages.

Thirteen percent of people admitted with asthma had a second admission within 90 days of discharge. 

• A high 90-day readmission rate suggests there may be room for improvement in discharge planning or continuity of care.
• In 2023, Pacific peoples (15.2 percent) were more likely to have a second admission within 90 days than European/Asian/Other (12.1 percent).
• There was limited variation between districts.

Fifteen percent of people admitted with asthma had a second admission within 91 to 365 days of discharge. 

• High readmission rates within three months to one-year post-discharge highlight the potential for community follow-up of people admitted with asthma.
• The percentage of people of Pacific (18.7%) and Māori (16.3%) ethnicity with at least two asthma admissions between 91 and 365 days was significantly higher than for European/Asian/Other (13.7%).

Thirty-four percent of people admitted with asthma were not regularly dispensed an ICS in the year after admission.

• It is recommended that all people admitted with asthma should regularly receive an inhaled corticosteroid (ICS) following admission. High rates of people not on a regular ICS in the year post-discharge raise questions as to why this might be. Is there potential to improve ongoing management?
• The rate of people with a primary diagnosis of asthma not dispensed ICS regularly in the year after admission was highest for the 5 to11-year age group (41.2 percent), compared to 30.8 percent and 24.4 percent for those aged 12–24 and 25–44 years, respectively.
• Children aged 0–4 years were not included in indicators looking at medication use because they are a unique group. Not all will respond to ICS therapy and of those who do, only some will have asthma at school age or as an adult.

Eighty-one percent of people did not receive a funded influenza vaccine in the year after admission

• Those who have a hospital admission for asthma are recommended to receive regular ICS therapy to manage their asthma. Influenza vaccine is also considered part of their preventive care. Pharmac funds the influenza vaccine for this group. For more information on eligibility criteria, see https://www.pharmac.govt.nz/medicine-funding-and-supply/what-you-need-to-know-about-medicines/vaccines/flu-season 
• Overall, the percentage of those hospitalised with asthma receiving the influenza vaccine was low during the 2019–2023 period, ranging from 19% to 23% of those admitted with a primary diagnosis of asthma. The exception was in 2020, when about 34% were vaccinated after hospital admission which could be due to the effects of the pandemic.
• There is a clear age effect with those in the older age group (65+ years) twice as likely to receive an influenza vaccination as those in younger age groups.
• Only 15 percent of 0–4 years, 12 percent of 5–11 years and 12 percent of 12–24 years received a funded influenza vaccine in the year following admission.
• There was limited variation between districts.
• Māori and Pacific peoples (respectively 89 and 86 percent) were significantly more likely to not receive an influenza vaccine compared with European/Other (77 percent).
• Influenza vaccines that are administered in hospital, self-funded or funded by another third party are not included here. It is expected that self-funded/alternatively funded is likely to be biased towards working-age groups. These exclusions are considered unlikely to explain the entire treatment gap.

Indicators (#7 and #8) looking at those in the general population who had a community dispensing of a reliever (SABA) inhaler and a preventer (ICS or other) in a year

• Children aged 0–4 years were not included in indicators looking at medication use because they are a unique group. Not all will respond to ICS therapy and of those who do, only some will have asthma at school age or as an adult.
• The data presented does not allow for analysis of patients’ condition or their need for treatment. This means it is not possible to assess the appropriateness, or otherwise, of prescribing. However, wide variation at the population level, both between districts and by age or ethnic group, is a starting point for asking whether the variation looks appropriate or if there are people who may benefit from preventer medication.

Twenty percent of those regularly dispensed SABA medication were not dispensed any preventer medication

• It is recommended that good control of asthma shows little use of SABA (reliever) medication [1]. Preventer (ICS or other) should be introduced if people are using their reliever two or more times in a week.
• This indicator shows that 20 percent of those dispensed a SABA in two or more quarters in a year, were not dispensed any preventer medication in the year.
• Pacific peoples (24 percent) were significantly less likely to receive preventer medication than Māori (19 percent) or European/Other (20 percent).
• Children aged 5–11 years were significantly less likely to receive preventer medication than all other age groups.
• There was about 1.5-fold variation between districts, ranging from 16.1-25.6 percent.

Thirty-one percent people regularly dispensed a SABA were not regularly dispensed a preventer medication

• Good control of asthma should show little use of relievers and regular use of preventers [1].
• This indicator shows that 31 percent of people regularly dispensed a SABA in two or more quarters in a year were not regularly dispensed a preventer (in two or more quarters in a year).
• Preventer use was significantly lower in those aged 5–11 years at around 60 percent, compared with 74 percent of those aged 25–44 years. These rates also varied by district; for example, rates ranged from 29.7 to 51.2 percent among children aged 5-11 years.

The rate of people aged 12–44 years dispensed a combined budesonide + formoterol inhaler has increased each year since 2018.

• Internationally, growing evidence shows that using SMART (Single Maintenance and Reliever Therapy) with budesonide–formoterol is associated with a longer time to first severe asthma exacerbation, compared to stepping up or continuing treatment with ICS–LABA plus SABA in patients with uncontrolled asthma [2]. 
• The 2020 New Zealand Adolescent and Adult Asthma Guidelines recommended a stepwise treatment algorithm incorporating budesonide + formoterol inhaler therapy as the preferred management following a similar inclusion in the Global Initiative for Asthma 2019 update [3].
• This indicator measures uptake of this inhaler, relative to other asthma inhalers.  Specifically, of all people who were dispensed any asthma inhaler (SABA, LABA, ICS or LABA/ICS combination), what percentage were dispensed a combined budesonide + formoterol inhaler.
• There have been large annual increases in dispensing of this inhaler since 2019 (17.6 percent in 2019 to 50.4 percent in 2023).
• Pacific peoples (44.5 percent) were less likely to receive combined budesonide + formoterol inhaler followed by Māori (49.8 percent) and European/Other (51.2 percent).
• There was little variation between age group or gender.
• There was about 1.5-fold variation between districts, ranging from 41 percent to 63 percent.

What questions might the data prompt?

• Why do some districts have consistently lower or higher rates than the national mean?
• Does this variation reflect differences in patient population or are there other local contextual factors such as housing, climate, air quality, healthcare access, infrastructure or workforce?
• How do districts with similar populations compare?
• At the practice level, how many practices have a mechanism to check which of their patients have had an asthma admission and follow-up if they have not rebooked within a certain period?
• How much impact can be attributed to the 2020 Adolescent and Adult Asthma Guidelines and/or the changes made during, and the effects of, the pandemic? Can the effects of these changes be replicated to regain and/or sustain any positive impacts observed?
• How can successful interventions be adapted, spread and scaled to other population groups?
• Why have the adult admission rates shown sustained improvement whilst children under 12 years admission rates have returned to, or surpassed (for Pacific children) pre-2020 rates?

The rates of medication use including ICS and influenza vaccine in the year after discharge raise questions as to why this might be

• What proportion of those not receiving an ICS were readmitted?
• What do patients understand about use of an ICS and reliever medication?
• How much of the gap can be explained by medication dispensing that is not captured, for example, prior to admission, free samples or oral steroids?

Background

Asthma is a chronic condition affecting the airways. Internationally, New Zealand has a high prevalence of asthma, with 12 percent of children aged 2–14 years (99,000 children) and 12 percent of adults aged 15 years and over (536,000 adults) reporting taking current asthma medication [4]. These rates are significantly higher for Māori and disabled children and adults.

The report The Impact of Respiratory Disease in New Zealand: 2024 Update presents data on asthma mortality rates [5]. In 2019, 101 people died from asthma. In 2014–19, asthma mortality was highest in people aged 65 and over, and significantly higher in women than in men for the 30 to 64 years and 65 year and over age groups. Asthma mortality rates were highest for Māori and Pacific peoples, with rates over two times higher than rates for those of non-Māori/Pacific/Asian ethnicity. There were socioeconomic differences in asthma mortality, with higher deprivation (quintile 9 and 10) rates being 2.63 times higher than the least deprived (quintile 1 and 2) rates. This inequity has increased since the 2018 report.

Data sources and method

The Atlas domain draws on existing national data collections held by the Ministry of Health, including the National Minimum Dataset and the Pharmaceutical Collection.

The indicators looking at admissions to hospital for asthma combines data for emergency department attendances meeting the three-hour rule for hospital admissions. This is because different DHBs handle emergency department attendances differently. For more information, see the methodology.

Read the methodology (PDF 765KB)

Read the methodology (DOCX 512KB)

Due to the uncertainty of diagnosing asthma in children under five years of age, ‘wheeze’ as an alternative diagnosis was included in the indicator reporting hospital admissions in children. Further analysis in the methodology demonstrates higher use of this code in the 0–4-year age group and significant variation between DHBs in the use of ‘wheeze’ as a diagnosis.

More information

• Asthma and Respiratory Foundation New Zealand Respiratory Guidelines 2020 (asthmafoundation.org.nz) 
• Review of the New Zealand Asthma and Respiratory Foundation's New Zealand Adolescent and Adult Asthma guidelines (nzmj.org.nz)
• The New Zealand Health Survey (health.govt.nz)
• The Australian Asthma Handbook 2022 (asthmahandbook.org.au)
• BTS/SIGN British Guideline on the Management of Asthma 2024 (brit-thoracic.org.uk)
• The New Zealand Health Survey Annual Data Explorer (minhealthnz.shinyapps.io)
• Asthma: are you practicing evidence-based medicine? Webinar (goodfellowunit.org)
• Asthma in under five-year-olds. Podcast recording (goodfellowunit.org)
• EPIC Asthma: Four data stories describing use of asthma medicines in New Zealand (epic.akohiringa.co.nz)
• Improving primary care management of asthma: do we know what really works?  (nature.com)

References

1. Beasley R, Beckert L, Fingleton J, et al. 2020. Asthma and Respiratory Foundation NZ Adolescent and Adult Asthma Guidelines 2020: a quick reference guide. NZ Med J 133(1517). URL: https://www.asthmafoundation.org.nz/assets/documents/ARFNZ-Adolescent-and-Adult-Asthma-Guidelines.pdf 
2. Beasley R, Harrison T, Peterson S, et al. Evaluation of Budesonide-Formoterol for Maintenance and Reliever Therapy Among Patients With Poorly Controlled Asthma: A Systematic Review and Meta-analysis. JAMA Netw Open. 2022;5(3):e220615.
3. Noble, J., Hatter, L., Eathorne, A., Hills, T., Bean, O., Bruce, P., Weatherall, M., & Beasley, R. (2024). Patterns of asthma medication use and hospital discharges in New Zealand. Journal of Allergy and Clinical Immunology: Global, 3(3), 100258.
4. Ministry of Health 2024. Annual Data Explorer 2023/24: New Zealand Health Survey. Wellington: Ministry of Health. URL: https://minhealthnz.shinyapps.io/nz-health-survey-2023-24-annual-data-explorer/
5. Telfar Barnard, L., & Zhang, J. (2024). The impact of respiratory disease in New Zealand: 2023 update. Wellington: Asthma and Respiratory Foundation NZ.