Single map Double map PHO analysis Consumer summary (247KB, pdf)

The asthma domain of the Atlas of Healthcare Variation gives clinicians, patients and providers an overview of asthma admission rates and medicine use by district health board (DHB). To increase diagnostic certainty and reduce the contribution from chronic obstructive pulmonary disease (COPD), only data for adults aged under 50 years are included.

You can get more information on the indicators, data sources, definitions, ages and rationale in the methodology (303KB, pdf).

Update 2018 data

(Data updated December 2019)

Key messages
  • Admission rates in young children aged 0–4 years are significantly higher than in children aged 5–14 years and adults.
  • Admissions for Pacific peoples and Māori are proportionally higher than European/other.
  • Fourteen percent of people had a second readmission within three months and 17 percent had a second readmission between three months and one year.
  • Forty percent of people admitted with asthma were not regularly dispensed an inhaled corticosteroid (ICS) in the year after admission in 2018. This is worse than in 2015, where 35 percent of people did not regularly receive an ICS in the year after admission.
  • Eighty-five percent of people admitted did not receive a funded influenza vaccine in the year after admission.
  • In the community, 21 percent of those regularly dispensed a short-acting beta agonist (SABA) in two or more quarters in a year, were not dispensed any preventer medication in the year, and 32 percent regularly dispensed a SABA were not regularly dispensed a preventer.

Key findings

Pacific and Māori children were more likely to be admitted than European/other
  • On average, 6 per 1,000 children (~5,600) were admitted one or more times with a primary diagnosis of asthma each year. Rates varied more than three-fold between DHBs.
  • Pacific children had the highest admission rate (11.8/1,000) followed by Māori (8.1/1,000) and then European/other children (4.3/1,000) These differences were all statistically significant.
  • Younger children (aged 0–4 years) had the highest rate of admission.
  • Boys aged 0–14 years were more likely to be admitted than girls.
Pacific and Māori adults (aged 15–49 years) were approximately three times more likely to be admitted with asthma than European/other
  • On average 0.9 per 1,000 adults were admitted one or more times in a year with a primary diagnosis of asthma.
  • In 2018, adult asthma admissions varied more than four-fold by DHB, from between 0.4 to 1.7 percent of a DHB population aged 15–49 years.
  • Females had more than twice as many admissions compared with males.

At all ages, on average 14 percent of those admitted with asthma had a second admission within 90 days

  • A high rate of admissions within 90 days of discharge suggests there may be room for improvement in discharge planning or continuity of care.
  • There was limited variation between DHBs.
  • From 2013 to 2018, the rate of second admission within 90 days for the 10–14-year age group progressively decreased by approximately 5 percent.
  • Since 2016, those aged 0–4 years have had the highest second admission rate.
  • In 2017 and 2018, people of Pacific and Māori ethnicities were more likely to have a second admission within 90 days than European/other.

Seventeen percent of people admitted had at least two admissions between 91 and 365 days of each other

  • High readmission rates within three months to one-year post-discharge highlight the potential for community follow-up of people admitted with asthma.
  • The proportion of people of Pacific (19.3/100) and Māori (18.8/100) ethnicity with at least two asthma admissions between 91 and 365 days was statistically significantly higher than for European/other (14.6/100).

Forty 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 ICS following admission. High rates 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?
  • On average, 40 percent of people aged 5–49 years admitted with a primary diagnosis of asthma did not receive an ICS in two or more quarters in the year after admission. This did not vary widely between DHBs.
  • Overall, the rates of people not dispensed an ICS in the year after admission have showed a temporary improvement by 5 percent from 2013 through to 2015. However, this was improvement was not sustained as rates worsened by 5 percent from 2015 through to 2018.
  • The rate of people aged 25-49 years who were not dispensed an ICS in the year after admission has gradually increased by approximately 10 percent from 2014 until 2018.
  • Pacific peoples were consistently significantly less likely to receive a regular ICS than European/other.
  • 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-five percent of those aged 0–49 years 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.
  • Overall, the percentage of those hospitalised with asthma receiving the influenza vaccine was low (13–28 percent of those admitted with a primary diagnosis of asthma).
  • There was limited variation between DHBs.
  • Māori and Pacific peoples (both 87 percent) were less likely to receive an influenza vaccine compared with European/other (83 percent).
  • Influenza vaccination was significantly lower in those aged 0–4 years (only 12 percent received it), compared with all other ages.
  • 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.
These indicators look 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 DHBs 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-one percent of those regularly dispensed SABA medication were not dispensed any preventer medication
  • It is recommended[1] that good control of asthma shows little use of SABA (reliever) medication. Preventer (ICS or other) should be introduced if people are using their reliever two or more times in a week.
  • This indicator shows that 21 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 (20 percent) or European/other (20 percent).
  • Children aged 5–9 years received significantly less preventer medication than all other age groups. This situation has worsened since 2012, increasing from 22 percent to 27 percent of children regularly dispensed a SABA and not dispensed preventer medication.
  • There was limited variation between DHBs.
Thirty-two 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 32 percent of people regularly dispensed a SABA in two or more quarters in a year were not also regularly dispensed a preventer (in two or more quarters in a year).
  • There was no significant variation by ethnicity. Preventer use was significantly lower in those aged 5–9 years at around 60 percent, compared with 71 percent of those aged 25–49 years. This did not vary widely by DHB.
What questions might the data prompt?
  • Why do some DHBs have consistently lower or higher rates than the national mean?
  • Does this variation reflect differences in patient population or are there other factors?
  • How do DHBs 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?
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 one in seven children (13 percent) aged 2–14 years (110,000 children) and one in eight adults (12 percent, 452,000 adults) reporting taking current asthma medication.[2] OECD statistics indicate New Zealand has one of the highest hospital admission rates for asthma of OECD countries.

The report The Impact of Respiratory Disease in New Zealand: 2018 Update presents data on asthma mortality rates.[3] In 2015, 87 people died from asthma. In 2010–15, asthma mortality was highest in people aged 65 and over, and higher in women than in men. Asthma mortality rates were highest for Māori and Pacific peoples, with rates 4.3 and 3.2 times higher than rates for those of Other ethnicity. There were socioeconomic differences in asthma mortality, with higher deprivation (quintile 9 and 10) rates being 2.2 times higher than the least deprived (quintile 1 and 2) rates.

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 (303KB, pdf).

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


References

  1. Beasley R, Hancox RJ, Harwood M et al. 2016. Asthma and Respiratory Foundation NZ adult asthma guidelines: a quick reference guide. NZ Med J 129(1445). URL: www.nzasthmaguidelines.co.nz/uploads/8/3/0/1/83014052/adult_asthma_guidelines.pdf.
  2. Ministry of Health. 2017. Annual Data Explorer 2018/19: New Zealand Health Survey. Wellington: Ministry of Health. URL: https://minhealthnz.shinyapps.io/nz-health-survey-2018-19-annual-data-explorer.
  3. Telfar Barnard L, Zhang J. 2019. The impact of respiratory disease in New Zealand: 2018 update. Wellington: The Asthma Foundation. URL: www.asthmafoundation.org.nz/research/the-impact-of-respiratory-disease-in-new-zealand-2018-update.

Last updated 19/03/2020