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Childhood ambulatory sensitive hospitalisations

Ambulatory sensitive hospitalisations (ASH) are mostly acute admissions that are considered potentially reducible through prophylactic or therapeutic interventions deliverable in a primary care setting.

Please note (Feb 2022):

Due to technical difficulties currently being resolved, the ASH Child atlas single and double map links are not able to be accessed. We apologise for any inconvenience. 

ASH child - single map

ASH child - double map

Ambulatory sensitive hospitalisations (ASH) are mostly acute admissions that are considered potentially reducible through prophylactic or therapeutic interventions deliverable in a primary care setting[1].

In New Zealand children, ASH accounts for approximately 30 percent of all acute and arranged medical and surgical discharges in that age group each year). However, determining the reasons for high or low ASH rates is complex, as it is in part a whole-of-system measure. It has been suggested that that admission rates can serve as proxy markers for primary care access and quality, with high admission rates indicating difficulty in accessing care in a timely fashion, poor care coordination or care continuity, or structural constraints such as limited supply of primary care workers[2]. ASH rates are also determined by other factors, such as hospital emergency departments and admission policies, health literacy and overall social determinants of health. This indicator can also highlight variation between different population groups that will assist with district health board (DHB) planning to reduce disparities.

Data for this Atlas were drawn from the National Minimum Dataset and present overall ASH rates by DHB. Data for conditions contributing the most to ASH rates in children (29 days–14 years) are presented. These conditions were selected with the assistance of an expert advisory group as being conditions possibly amenable to primary care interventions. The conditions were: dental, otitis media/upper respiratory tract infections, asthma, gastroenteritis, pneumonia and cellulitis/skin infections.

There is considerable debate about the appropriateness of the term ASH and its definition. While ASH rates have traditionally tended to focus on primary care provision (particularly in general practice), it is important to remain aware that many other aspects of the health care system – hospital supply and configuration, emergency care department management, community care provision etc – can have an effect on ASH. Underlying determinants of health such as housing quality, exposure to second-hand cigarette smoke, household crowding and poverty may also influence the incidence of ASH conditions in the community.

For these reasons, both the Ministry of Health ASH and a modified version of ASH are presented. ‘Modified ASH’ allows people to further interrogate this dataset by removing filters and exclusions normally applied to ASH data. The removal of filters and exclusions allows users to see all ASH events, including emergency department admissions and non-casemix events. To view methodology click here. Modified ASH is intended to highlight the impact these filters have on ASH rates and promote the concept of ‘hospitalisations for whole system sensitive conditions’.

It is important to note the deliberate use of the word ‘sensitive’ in the title of ASH – not all these admissions would be preventable even in a perfect health system. Moreover, many ‘unplanned’ admissions are planned in the acute sense by the primary care clinician, and are not ‘avoidable’ given current health service resources, and the psycho-social circumstances of children and their families.

For all of the conditions in the Atlas, many of the admissions are warranted using present health system conditions. As the primary diagnoses for each hospital admission are assigned at discharge, once the majority of investigations have been completed, it may be that many children with apparently minor ASH-related conditions may have in fact been admitted for investigations to exclude more serious non-ASH conditions (eg, meningitis). Hence, zero is not the sought target here.

In children, infectious causes of admission are the most common and the onset tends to be sudden. For each ASH condition there are different pathways to improved care, for example, for asthma it may be the use of preventative medicine, whilst gastroenteritis may be about access to early oral rehydration fluids.

It is possible that some of the variations observed in this Atlas are due to variations in coding and differences in how DHBs manage the three-hour emergency department rule. Where coding appeared to be a possible cause for observed variation, this is noted in the commentary.

Key messages:

Overall ASH rates varied two-fold between DHBs. Admissions were significantly higher for each of the younger age bands, as were admissions for Māori and Pacific children.

Younger children (0–4) were significantly more likely than children aged 5–14 years to be admitted for infectious conditions: otitis media/upper respiratory tract infections, gastroenteritis, pneumonia and cellulitis/skin infections.

Admission rates for Māori and Pacific children were higher for dental, asthma and cellulitis/skin infections, whilst Pacific children had significantly higher admission rates for pneumonia compared with all other ethnic groups.

A three-fold variation in admission rates by DHB was observed for otitis media/upper respiratory tract infections and cellulitis/skin infections.

In reporting these rates, the intention is not to prevent all admissions but to question:

  • How might high rates of admissions be affected by more intensive support for primary care management?
  • How do health literacy, service provision, primary care access and prevention programmes impact on admission rates?

Recommended reading

Starfield B, Shi L, Macinko J. 2005. Contribution of Primary Care to Health Systems and Health. The Milbank Quarterly 83(3): 457–502.

Kringos DS, Boerma WGW, Hutchinson A et al. 2010. The breadth of primary care: a systematic literature review of its core dimensions. BMC Health Services Research 10 65.

World Health Organization. 2008. The world health report: primary health care now more than ever. Geneva: World Health Organization. URL:

New Zealand Child and Youth Epidemiology Service:


  1. Jackson G, Tobias M. 2001. Potentially avoidable hospitalisations in New Zealand, 1989-98. Aust NZ J Public Health 25(3): 212–21.
  2. Kruzikas D et al. 2004. Preventable Hospitalizations: A Window into Primary and Preventive Care. HCUP Fact Book 5, 0056.
Last updated: 18th May 2022