bestpractice Childhood Asthma module produces results

Evaluating the bestpractice Decision Support and bpacnz Childhood Asthma programme.

Executive summary

In April 2009, the bestpractice Decision Support Childhood Asthma module was released to all general practitioners in New Zealand, funded by Pharmac. As of November 2010, 3,331 general practitioners have access to the module. Coinciding with the release of the bestpractice module, bpacnz produced an education programme on childhood asthma which included a Special Edition of Best Practice Journal, and a report personalised for every general practitioner on their prescribing for children with asthma.

The evaluation of the programme focused on the key data indicators of hospitalisations for asthma related diagnoses for children under 15 who were assessed with the bestpractice module, which was based on child-years at risk*. The evaluation also included analysis of prescribing for asthma drugs for children under 15 by general practitioners who used the bestpractice module, comparing one year before and one year after the education programme launch.

The results of the evaluation showed that children with asthma who were managed with the bestpractice module were significantly less likely to be hospitalised with an asthma related diagnosis following their assessment with the bestpractice module than they were before (p=0.01). In addition, although there was no change in the pattern of prescribing of asthma medicine in general, the users of the bestpractice module showed a reduction in the reliever:preventer ratio of their patients (p=0.01).

Programme background

New Zealand has one of the highest rates of childhood asthma in the world, with 20% of children having ashma.1 The programme aimed to improve outcomes for children with asthma through education for general practitioners, children, and family members and advocacy of the correct approach to prescribing and managing asthma in primary care. The key objectives of the programme were:

  • Increase recognition and knowledge of asthma in general practice
  • Increase the correct prescribing and use of inhaled corticosteroids
  • Increase knowledge and confidence of children with asthma and their families

Programme activities

  • bestpractice Decision Support Childhood Asthma module including Asthma Action Plan, April 2009
  • Best Practice Journal Special Edition ‘Childhood Asthma’, May 2009
  • Prescribing for Children with Asthma GP Report, May 2009


  • The bestpractice Decision Support Childhood Asthma module was reviewed by Dr Peter Cardon, Professor Murray Tilyard, Dr Malcolm Kendall-Smith, Dr Hywel Lloyd, Associate Professor David Reith and the Pharmac Review Group.
  • Carol Fitzgerald, Respiratory Clinical Nurse Specialist, Otago District Health Board contributed to the development of the bpacnz programme material.

Key data indicators

bestpractice activity

The bestpractice Decision Support Childhood Asthma module was made available in April 2009 and is nationally funded for all general practitioners by Pharmac. To date, 952 general practitioners (29% of all New Zealand general practitioners) have accessed the module a total of 3374 times.

Hospitalisations for asthma

Asthma is the leading cause of childhood hospital admissions,1 for this reason a key indicator of the success of the programme is the effect it had on hospitalisations for asthma in children. This analysis included diagnoses of asthma and related diagnoses including bronchitis, bronchiolitis or pneumonia (International Classification of Diseases codes 466, 480-6, 490-1, 493) to avoid the possibility of missing relevant hospitalisations due to diagnostic transfer.2 Figure 1, below, shows that the number of these hospitalisations are highly affected by the season, with children being more likely to be hospitalised during winter months than in the summer.

Figure 1. Asthma related hospitalisations for patients under 15

Between the launch of the programme in April and the end of 2009, 378 children aged under 15 were assessed with the bestpractice module. As of November 2010, of these patients 65 (17%) have been assessed two times, 25 (7%) have been assessed three or four times, and 12 (3%) have been assessed five or more times. This indicates that ongoing management of these patients is taking place. This cohort was selected because data on hospitalisations is not available past the end of 2009.

Based on the child-years at risk for the cohort, there were an average of 25.5 hospitalisations per 100 child-years prior to their first assessment with the bestpractice module, and an average of 12.1 hospitalisations per 100 child-years following assessment. This represents a rate-ratio of 2.1:1 hospitalisations before compared to after (95% CI = 1.2 to 3.7, p=0.01). The days at risk for this cohort following their assessments with bestpractice were primarily during winter months where, as shown in Figure 1, we would expect the rate of hospitalisations to increase rather than decrease.

Figure 2. Hospitalisations per 100 child-years for bestpractice cohort

Reliever:preventer ratio

The ratio of reliever to preventer used can be considered a measure of adherence to an optimal treatment regimen. In patients with well controlled asthma we would expect the ratio of relievers to preventers to be low.3 To evaluate the effect the programme had on prescribing in general, data from the NZHIS Pharamceutical Data Warehouse was collected and analysed for one year before and after the programme launch.

In the group of all prescribers, there was little change before and after the programme. In the group of general practitioners who used the bestpractice module, there was a significant reduction in the ratio of relievers to preventers dispensed, falling from an average of 2.9 before to 2.7 after the programme (p=0.01). There are, however, considerable ethnic disparities in the reliever:preventer ratio.

Table 1. Reliever:preventer ratio before and after

Users (952) Non Users (6,835)
  Before After Before After
Māori 3.7 3.5 3.9 3.8
Pacific 4.1 3.7 4.5 4.8
Other 2.5 2.3 2.6 2.6
Total 2.9 2.7 3.0 3.0

Table 1 shows the reliever:preventer ratio by ethnicity, and compares the ratio prescribed by users of bestpractice and non users. It shows that among the general practitioners who used the bestpractice module, the reliever:preventer ratios have been reduced across all ethnic groups following the programme but this was only a statistically significant reduction in the population of non Māori and non Pacific children (p=0.02), and the overall cohort (p=0.01), as indicated in the table by italics. This is explained by smaller numbers of Māori and Pacific children being prescribed asthma medicine due to the smaller population.


The evaluation of prescribing data showed that the users of decision support modules are guided by their recommendations. The analysis of hospitalisation data showed that patients who are assessed with the bestpractice Childhood Asthma module experienced improved outcomes following their assessment with the module, it would be of interest to revisit this when more data is available.

* Child-years at risk were based on the amount of time between the child’s first assessment with bestpractice and the end of 2009, counting hospitalisations in this time and the same amount of time before their assessment with bestpractice to provide a comparison in the number of hospitalistaions before and after.

Data from the NZHIS Pharmaceutical Data Warehouse was analysed for one year before and one year after the programme launch, 1 May 2008 to 30 April 2009 and 1 May 2009 to 30 April 2010, respectively.

Includes non general practitioners, for example hospital doctors.