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| Journal of the New Zealand Medical Association,
16-May-2003, Vol 116 No 1174
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Asthma morbidity, control and treatment in New Zealand:
results of the Patient Outcomes Management Survey (POMS), 2001
Shaun Holt, Marjan Kljakovic and Jim Reid, for the POMS
Steering Committee
Asthma is one of the most common chronic diseases in New
Zealand and is the most common cause of hospital admission in
children.1,2 New Zealand has one of the highest
prevalence rates of asthma,3–5 with
Maori, Pacific Islanders and low socioeconomic groups disproportionately
affected.6,7 A recent publication by the Asthma
and Respiratory Foundation of New Zealand has estimated the medical and economic
costs of asthma in New Zealand to be over $800 million every
year.8
The burden of asthma throughout the world in terms of
morbidity, mortality and economic cost is
considerable.9 Recent community-based surveys
in Europe, the United States and the Asia-Pacific regions have shown that the
level of asthma control usually falls far short of the recommended
goals.10–12 For example, throughout these
regions, around 30% of patients with asthma reported waking with breathing
problems at least once a week. Also, over 40% of children with asthma had missed
school and over 20% of adults with asthma had missed work within the previous 12
months due to their condition. Furthermore, over one third of individuals with
asthma were either hospitalised, treated in an emergency department or required
other urgent care for their asthma in the previous 12 months.
These findings contrast with the goals of asthma management
described in the GINA (Global Initiative for Asthma)
guidelines:9
Only 5% of asthmatics surveyed in seven
countries in Europe met all of these
goals.10
The Patient Outcomes Management Survey (POMS) was undertaken
in New Zealand in 2001 in order to assess the magnitude of the morbidity from
asthma in the population, to assess the level of asthma control in a randomly
selected sample of adults and children from a general practice setting, and to
correlate these findings to the treatment received.
MethodsThis
was a multi-centre, national study of asthma control, performed in a general
practice setting. Data were collected from 327 adults and 118 children from 29
general practices chosen randomly from across New Zealand.
A computer programme was used to place all practices in New Zealand in a random order. Practices were then approached sequentially and invited to take part until a sufficient number had agreed. The aim was to recruit 400–500 patients, adult or children, from approximately 30 general practices, but this was not based on formal power calculations. In each practice, asthmatic patients who had been prescribed medication for asthma in the previous year were randomly chosen from computer or paper-based records and invited to participate until approximately 15 patients had been recruited. The definition of asthma used was ‘doctor diagnosis of asthma’. There are many definitions and diagnostic criteria for asthma, but no gold standard. ‘Doctor diagnosis’ is easy to use and has a high specificity and positive predictive value. For each participant in the survey, the following data were collected:
Morning, day and night symptom
frequency were recorded as: never; 1–2 times a month; 1–2 times a
week; or every day. Activity-induced asthma was classified as: rarely; with
exercise or sports; with hills, stairs or active play; or with walking on the
flat.
Participants were classified according to their prescribed treatment step in the British Guidelines of Asthma Management (BGAM):15
In the
analysis, a child was defined as 7–15 years of age inclusive. Data
analysis was undertaken using Microsoft Excel and SAS. Ethics committee approval
was obtained for the study from all New Zealand Ethics
Committees.
Definitions of asthma control and under-treatment The only globally standardized criteria for asthma control are those of the GINA guidelines described above. However, for the vast majority of patients with asthma, this level of control is unrealistic. Therefore, two further criteria of control were developed, based on the frequency and severity of symptoms and lung function (Table 1). These criteria were developed for the purposes of this study and therefore require further validation. Table 1. Definition of asthma control in patients whose
asthma was sub-optimally controlled, not well controlled, or markedly out of
control
‘Sub-optimal control’ equates to a patient
not achieving a level of control similar to that described in the GINA
guidelines, ie, not optimally controlled. For a classification of ‘not
well controlled’ at least two of the listed goals must be breached; for
example, this definition will not include those who use their reliever inhaler
out of habit or as a prophylactic before exercise. Finally, the definition of
‘markedly out of control’ represents a level of symptoms that would
cause a major interference in the patient’s life. ‘Not well
controlled’ and ‘markedly out of control’ are subsets of
‘sub-optimal control’, and ‘markedly out of control’ is
a subset of ‘not well controlled’.
Further, the proportion of each group who were under-treated was estimated. Patients classified as not well controlled were considered to be adequately treated if they received either:
Patients classified as markedly
out of control were considered to be adequately treated if they
received:
It
should be noted that for both groups an increase in treatment may not
necessarily lead to clinical improvement but that the level of symptoms
experienced warrants that increase.
ResultsThree hundred and twenty seven
adults and 118 children from 29 general practices took part in the survey.
Eighty three per cent of practices that were approached agreed to take part and
approximately 75% of patients who were approached by their practice opted to
take part in the study. The demographics of the participants and their
classification with the BGAM steps are presented in Table 2.
Table 2. Patient demographics
BGAM = British Guidelines of Asthma Management
NB: some percentages do not add up to 100 due to rounding The proportions of those classified as either sub-optimally
controlled, not well controlled, or markedly out of control were compared to
BGAM step (Table 3).
Table 3. Level of asthma control according to the
British Guidelines of Asthma Management (BGAM) in adults and children
(NB: ‘not well controlled’ and
‘markedly out of control’ are subsets of ‘sub-optimal
control’, and ‘markedly out of control’ is a subset of
‘not well controlled’)
Data on the use of health services for asthma and the impact
of asthma on work and school are outlined in Table 4. This table also includes
some important findings from the questionnaires, including time off school or
work, contacts with health services and satisfaction with asthma
control.
Table 4. Key results from the questionnaires
The use of medication in those patients whose asthma was not
well controlled or markedly out of control is presented in Table 5.
Table 5. Medication use by patients whose asthma was
not well controlled or was markedly out of control
All
ICS doses are μg/day beclomethasone dipropionate or
equivalent
ICS = inhaled corticosteroid; LABA = long-acting β-agonist Finally, the proportion of each group who were under-treated
was estimated according to the method described above. Those who are considered
to be under-treated are represented in bold in Table 5.
DiscussionThis study represents a snapshot of
current asthma morbidity and management in New Zealand. The major finding was
that a majority of adults and children with asthma were not well controlled
according to the criteria used. This applied across all BGAM steps, implying
that patients across the spectrum of asthma severity were not well controlled.
The results are comparable to those observed in similar studies conducted
overseas.
A possible selection bias may have occurred in that only
patients who had been prescribed asthma medication in the previous year were
invited to take part. This could have resulted in the exclusion of a small
subset of very mild asthmatics but this is unlikely to have had a significant
impact on the findings.
The definitions of asthma control used in this study have
been adapted from the GINA guidelines to capture the spectrum of asthma control
levels. It would have been hoped that more than around 10% of adults and
children would have achieved a better level of control than the sub-optimal
control criteria. Furthermore, the findings that 72% of adults and 44% of
children have asthma that is not well controlled are unexpectedly high and it is
of great concern that around one fifth of adults and one twentieth of children
fall within the category of markedly out of control.
The findings of this study highlight some of the costs of
poor asthma control. Around 10% of asthmatics had missed school or work in the
previous month due to their condition. In the previous three months, two thirds
of adults and children had contacted a GP about their asthma, often out of
hours, and about 10% had been to the emergency department or had been admitted
to hospital with asthma in the previous year.
Some of the most important findings from this study were
those concerning patients’ expectations about their condition and
management. There was a striking mismatch between the patients’ perception
of asthma control and the actual level of control as defined in this study.
Overall, 76% thought that their asthma was well controlled and 80% were
satisfied with their level of control. It would appear that, despite significant
symptoms, these patients considered themselves to be ‘normal’ for a
person with asthma. It would follow that these symptoms may not be reported to
their doctor. This emphasises the need for diligent assessment of patients with
asthma at each clinic visit.
In addition, despite their simplicity and proven
effectiveness, only 36% of patients had a written asthma management
plan.16
It was beyond the scope of this study to assess patient
compliance with treatment. Compliance with treatment for chronic conditions is
often poor, usually due to the dislike of having to take medications
continuously or the fear of side effects.
Finally, this survey has revealed that for those whose
asthma is not well controlled, 49% of adults and 71% of children are
under-treated. For those whose asthma is markedly out of control, 89% of adults
and 75% of children are under-treated. Whilst it was beyond the scope of this
study to determine the reasons for this degree of under-treatment, a possible
explanation includes the mismatch in patients’ perception of asthma
control and actual control. The widespread under-treatment that was seen may in
part be due to local restrictions placed on the prescribing of newer medications
such as long-acting
β-agonist drugs
and the inhaled corticosteroid/long-acting β-agonist combinations. It is
also likely that problems in accessing GP care have contributed to this level of
under-treatment.
Author
information:
Shaun Holt, Director, P3 Research, Wellington; Marjan Kljakovic, Senior
Lecturer in General Practice, Wellington School of Medicine and Health Sciences,
Wellington; Jim Reid, Head of General Practice and Associate Dean for
Postgraduate Education, Dunedin School of Medicine, Dunedin
Acknowledgements:
This study was fully funded by GlaxoSmithKline New Zealand. The project was
designed by Sarah Teale of GlaxoSmithKline and the Steering Committee and was
managed by Jo Pirihi of GlaxoSmithKline. The Steering Committee consisted of the
authors of this paper and Jenny Shieff of the Asthma and Respiratory Foundation
of New Zealand, Jeanette Reid of the Asthma Society, and Ian Griffiths, Peter
Schweikert and Christine Weston of GlaxoSmithKline.
The GPs who helped with this study were: Dr John Crawford,
Dunedin; Dr Colin Bennett, Manurewa, Auckland; Dr Simon Kay, Onehunga, Auckland;
Dr Deon Heyns, Palmerston North; Dr Claude Preitner, Rotorua; Dr Allan Crighton,
Kaiapoi; Dr Graeme Kidd, Howick, Auckland; Dr S Hicton Burnett, Devonport,
Auckland; Dr Lew Johnson, Linwood, Christchurch; Dr John Arcus, Beachaven,
Auckland; Dr John Sumich, Henderson, Auckland; Dr Hein Strydom, Wanganui; Dr
Deon Claassens, Te Atatu, Auckland; Dr Nick Gailer, Kumeu; Dr Andrew Costello,
Gore; Dr Chris Beer, Mt Albert, Auckland; Dr R Wilson, Mt Albert, Auckland; Dr
Murray Smith, Gisborne; Dr Murray Shaw, Palmerston North; Dr Jim Corbett.
Marton; Dr Sharad Paul, Blockhouse Bay, Auckland; Dr Diana Good, Mt Eden,
Auckland; Dr E Wong She, Palmerston North; Dr Pat Hill, Lambton Quay; Dr Frank
Weihahn, Hastings; Dr Shirley Wallace, Brown’s Bay, Auckland; Dr Danny
Neave, Frankton; Dr Anne Brown, Blenheim; Dr Steve Philip, Upper Hutt; Dr Mike
Williams, Rotorua; Dr Mitch Blake, Upper Hutt.
Correspondence: Dr.
Shaun Holt, P3 Research, Level 2, 61-63 Taranaki Street, Wellington. Fax: (04)
914 4643; email: shaun@p3research.co.nz
References:
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