Asthma-related medicines
Asthma-related medicines use and morbidity
The following information on the use of asthma medicines derives from various in-house compilations and analyses undertaken by PHARMAC staff between 2006 and 2008.
Disparities in asthma management
Approximately 20% of children in New Zealand have asthma; this is one of the highest prevalence rates in the world (Asher 2001). Asthma is a leading cause of childhood admissions to hospital and the third-ranked cause of years lost to disability in New Zealand (Holt and Beasley 2001). During the 12 months to May 2007, 4433 children were admitted to hospital with asthma in New Zealand.
Māori and Pacific children are 2–3 times more likely to be admitted to hospital for asthma than New Zealand European children despite a similar prevalence of asthma (Figure 1). The disparity is greatest in preschool-aged children. Asthma symptoms are more severe amongst Māori children than NZ European children (Holt and Beasley 2001).
The ratio of short-acting beta-agonist (reliever) inhaler (SAB) to inhaled corticosteroid (preventer) inhaler (ICS) dispensings is higher in Māori and Pacific children (3.7 and 4.15, respectively) than in NZ European children (2.63), suggesting a greater unmet need for preventive treatment in Māori and Pacific children. The ratio of SAB to ICS dispensings is an indicator of possible diminished quality of asthma treatment in populations (Shelley 1996; Frischer 1999; Anis 2001), and relates to outcomes measures such as hospitalisation rates. Figure 12 correlates medicines use with hospitalisation rates for Māori, Pacific and NZ European children for each district health board.
Reasons for ethnic disparities in asthma management are numerous and cannot be comprehensively described here. They include barriers to accessing primary care for Māori and Pacific people, differential primary care treatment of Māori and Pacific people compared with other New Zealanders, lack of access to culture-specific asthma education, barriers to understanding, and factors affecting adherence to prescribed medicines. Differential prescribing of ICS and provision of action plans to Māori compared with other New Zealanders has been documented (Holt and Beasley 2001).
Figure 1: Asthma hospitalisations for year ending May 2007
Table 1.
The graphs below show the SAB:ICS ratio on the left and the asthma (Glossary description: Asthma is a common chronic disorder of the airways that is complex and characterized by variable and recurring symptoms, airflow obstruction, bronchial hyperresponsiveness (bronchospasm), and an underlying inflammation.) hospitalisations on the right for people aged under 19 years, across DHBs, for different ethnic groups. Data shown is for the year ending December 2008. The yellow shading indicates the lowest SAB:ICS ratio or hospitalisation rate (indicators of possible better asthma care or lower need) while red indicates the highest ratio or rate (indicators of possible poorer asthma care or higher need).
Figure 2a: NZ SAB:ICS ratio and asthma hospitalisations
Figure 2b: European SAB:ICS ratio and asthma hospitalisations
Figure 2c: Maori SAB:ICS ratio and asthma hospitalisations
Asthma hospitalisation rates 2003/04 x age x ethnicity
Asthma drug use by ethnic group
According to age-standardised rates of dispensing equivalents in 2003/04 in patients with likely asthma aged 0-34, the use of LABAs is much higher in NZ Europeans than other ethnic groups. Conversely, rates of ICS use were the same for NZ Europeans and Māori, but less for Pacific patients. Rates of SABA use were highest in Māori and lower in Pacific patients, which contrasted with the highest rates of hospitalisations occurring in Pacific patients (see figures and table below).
Asthma Rx use and hospitalisations in asthma patients - by ethnic group, 2003/04
Relative patterns of asthma Rx use and hospitalisations in children aged 5-14 with asthma - by ethnic group, 2003/04, relative to NZ Europeans
Combining the above patterns, then relative to NZ Europeans, Māori and especially Pacific patients had higher SABA/ICS ratios (suggesting poorer asthma control) and lower ICS/hospitalisation and LABA/hospitalisation ratios (suggesting unmet need, where hospitalisation proxy higher need than in NZ Europeans) – see figures and table below.
SABA to ICS (incl. Symbiocort) ratios in 2003/04 by ethnic group - suggesting poorer asthma control
ICS to hospitalisation ratios in 2003/04 by ethnic group - suggesting unmet need for asthma Rx in some groups (from age-standardised rates ages 0-34)
LABA (incl. Symbiocort) to hospitalisation ratios in 2003/04 by ethnic group - suggesting unmet need for asthma Rx in some groups
