5.9.3. Data description and analysis
With respect to its natural history, asthma presents two
different forms: early- and late-onset asthma.
The first one occurs in the very first childhood, affects
mainly males and has a good prognosis; the second one, in general, occurs after
puberty, in particular in females, and is characterized by a poor prognosis.
Different studies have pointed out that people with
early-onset asthma have a greater percentage of remission than people with
late-onset asthma and the minority of the patients with early-onset asthma
represents about 35% of prevalent cases of the young adult population (20-44
years of age) (de Marco, 2000).
Previous studies described the history of asthma in
childhood and in adulthood separately, observing that the possibilities of
remission are high in children and low in adults; nevertheless, such a clean
division between early- and late-onset asthma has not been noticed before for
the limited age range considered in the surveys. These first results can be
compared with those obtained in another study (de Marco et al, 2002),
aimed at assessing the incidence and remission of asthma from birth to the age
of 44 by using data from 18,873 subjects involved in a large, nationally
representative, cross-sectional study carried out in Italy from 1998 through
2000. The average annual incidence rate for the 1953 to 2000 period was
2.56/1000 people per year. Incidence peaked in boys aged less than 10 years
(4.38/1000 people per year) and in women aged 30 or more (3.1/1000 people per
year) and showed a generational increase (incident rate ratio = 2.63 and 95% CI
= 2.20-3.12 for 1974-1979 vs 1953-1958 birth cohort). The overall remission
rate was 45.8% (41.6% in women and 49.5% in men, P <.001). Asthmatic
patients in remission had an earlier age at onset (7.8 vs 15.9 years, P
<.001) and a shorter duration of the disease (5.6 vs 16.1 years, P <.001)
than patients with current asthma. The probability of remission was strongly (P
<.001) and inversely related to the age at onset (62.8% and 15.0% in the
<10- and > or =20-years age-at-onset groups, respectively). Further
studies are necessary to achieve a deeper knowledge of the natural history of
asthma, from birth to adulthood, and, consequently, a better understanding of
its aetiological causes and its epidemiological features.
Prevalence rates
ISAAC showed a more than 20 fold difference in prevalence
data between the different centres, varying from from 3.7% in Greece to 32.2% in UK. The existence of a significant correlation (P<0.0001) between the
prevalence of asthma and rhinitis symptoms was also shown. In fact, countries
with a low prevalence of asthma, such as Greece, presented also a low
prevalence of rhinitis, while in other countries (such as the UK), where asthma prevalence was higher than 30%, allergic rhinitis prevalence also
resulted to be higher than 15%. In Italy, the prevalence in tha same age range
varied from 2.5% to 3.5% in the different centres where the data were
collected.
The results of the 
European Community
Respiratory Health Survey (ECRHS) (Burney et al, 2004) have shown once again that
the prevalence of asthma varies widely, whilst the geographical pattern
reflects the distributions of atopy and bronchial hyperresponsiveness. The
prevalence data were compared with the results from the ISAAC: the estimates in
ECRHS were lower; however, there was a good correlation between asthma (74% of
country level and 36% of centre level variation explained), hay fever (61 and
73%) and eczema (41 and 50%) in the ECRHS and the corresponding data in the ISAAC.
These findings can be supported by the different pattern in the prevalence of
allergic symptoms provided in adulthood and childhood.
Figure 5.9.1. Wheeze in last 12
months in ECHRS and ISAAC phase I by country
Figure 5.9.2. Asthma ever in ECHRS
phase II and ISAAC phase I by country.
Figure 5.9.3. Asthma by age 14 years
in ECHRS and ISAAC phase I by country
Figure 5.9.4. Hay fever in ECHRS and
ISAAC phase I by country.
The AIRE study (Asthma
Insights & Reality in Europe) (Blanc et al, 2002) identified a total population
prevalence of current asthma of 2.7% for the seven AIRE countries (Sweden, France, Italy, Spain, United Kingdom, Netherlands and Germany). The epidemiological results
were globally similar among the seven countries included in the survey;
however, the mean age at diagnosis (9.6 years) and the predominance of males
among asthmatic patients were most remarkable in German children (p < 0,05)
The survey by Compalati et al, 2007 reported that the
highest prevalence rates of asthmatic symptoms in European countries were
registered in the UK - which reported 19% prevalence in adults and 35% in
children - while the lowest was in Iceland - which reported 2%; in the middle
of this scale. The other countries considered were: Portugal (the most recent
data available indicate a 12.9% of prevalence in children, 14.7% in
adolescents, while in 1992 an estimate of 4.4% among adults was recorded),
Bulgaria (9% in the total population), Latvia (8.2%), Czech Rep.(8% of the
general population: 11.2% in children of 6-7 years of age and 16.9% in children
of 13.14 years of age), Romania (7%), Switzerland (9.1% in children and 6.8% in
adults), Spain (6.3%), Croatia (6%), Serbia (6%), Greece (5.6%), Poland (5.4%),
Germany (2.5%), Hungary (4%), Macedonia (3.3%) and Italy (3.2%).
Allergic rhinitis is a very common disease. As far as AR prevalence is
concerned, the highest rates have been declared by Portugal, which has reported
an increase in prevalence during the last three years, from 24% to 26% in the
age group 15 years and older, while adolescents 13 to 14 years old presented a
37.1% prevalence. The other countries presented the following prevalence data:
Greece 27.5%, Macedonia 20.8%, Bulgaria 18.3%, Latvia and Hungary 17%, Romania
15%, Switzerland 14.2% in adults and 17% in children, Czech Rep. 12.5%, Croatia
12.1%, Serbia 11.6%, Iceland 11%, Spain 10.6% and Poland 8.5% and Germany 3%.
These results show that there are considerable differences among European
countries.
Actually, these data are likely to underestimate the
disease because many people do not undergo any medical evaluation. In the nine centres participating to the
Italian Study on Asthma in Young Adults (ISAYA) (Bugiani et al, 2005), the
prevalence of allergic rhinitis varied between 13.5% and 23.6% (median 18.9%)
in 1998–2000. The AllergyNet of the May 2007 issue of Allergy (Mantovani et al,
2007), reported that in 2003 the prevalence of allergic rhinitis in Italy amounted to 4.5% since the end of 1990s, based on the national database of general
practitioners. As acknowledged by the Authors themselves, this figure is much
lower than the prevalence estimates recorded by questionnaire-based surveys.
Indeed, in people from Northern Italy aged 20–45, the prevalence of allergic
rhinitis was 15.9% according to the European Community Respiratory Health
Survey (ECRHS) in 1991–93 and had increased to 18.3% by the end of the 1990s.
Trends in prevalence rates
A substantial increase in asthma prevalence has been
emphasized in several reports since the early 60s. The review by von Hertzen and
Haahtela (tables 5.9.1 to 5.9.3) identified that in 13 of the 20 studies
reviewed, a decreasing or stable trend for asthma or current wheeze at any time
during the study period was reported. It has been emphasized in several EU
countries (such as England, Italy), and elsewhere (Australia, USA), that the rising trends in asthma prevalence among adults may have reached a plateau
or may even be decreasing, after having increased for decades. Data on children
are more contradictory: many studies have shown stable trends in childhood
asthma since the late 90s (Greece, United Kingdom), while others have shown a
steadily rising asthma prevalence (East Germany, Australia).
Table 5.9.1. Summary of data on
stable or decreasing trends in prevalence of asthma
Table 5.9.2. Summary of data on
continuously increasing trends in prevalence of asthma
Table 5.9.3. Summary of studies
showing disparities in trends for asthma and allergic rhinitis
Most centres involved in the different phases of the ISAAC
studies showed an increasing prevalence of 1 or more standard error at least one disorder, more commonly in the 6–7 years of age-group
than in the 13–14 years of age-group: for the 6–7 years of age-group, two of
the 64 centres recorded reductions in all three disorders, 16 recorded
increases, and 45 mixed changes (one centre actually reported no changes); for
the 13–14 years of age-group, 11 of 105 centres registered decreases in all
three disorders, 20 showed increases, and 74 showed mixed changes. For both age-groups,
more centres showed increases in all three disorders more often than showing
decreases, but most centres had mixed changes; on the contrary, asthma symptoms
were less common in the older age-group at high prevalence. There was a
particularly marked reduction in current asthma symptoms prevalence in English
language countries. These data provide a basis for a better understanding of
these pathologies, since this epidemiological pattern seems to be related to
environmental and socio-economic factors.
Although mortality is low, most asthma deaths result from
acute exacerbations and are generally thought to be avoidable. Death from asthma
may thus be considered a sentinel health event of the access to and the quality
of outpatient health care.
Deaths due to asthma are estimated to be 250,000 per year
worldwide. EU mortality due to asthma
(death defined by ICD-10 J45-J46) is low and Standardized Death
Rates (per 100,000 people) in all EU Countries are significantly decreasing
over time, but for the Netherlands, no decrease in mortality has been observed
since 1994(Figure 5.9.5.)
Figure 5.9.5. Trends in mortality due
to asthma in selected EGLOUREH countries
Data provided by the National Asthma Campaign (UK)
concerning asthma primary care serving a population of 330000 people suggest
that: 665.000 people with wheezing are visited in a year of observation, 44900
had asthma diagnosis, 25100 received treatment from general practitioner, 493
were the emergency admissions, 8 patients died. (Lung Health in Europe, 2003 ERJ)
According to the “European Allergy White Paper” (Allergic diseases as a
public health problem in Europe, The UCB Institute of Allergy, 1997), health
care providers and authorities are becoming progressively aware that allergic
disorders represent a major and increasing factor in public health costs.
Although they can be calculated with difficulty because of the lack of adequate
data, they are estimated - in terms of health care and absenteeism, for example
- at 45 billion euros a year. Allergies impair the quality of life over a long
period, resulting in a continuous drain on public health resources and loss of
workdays. For a better evaluation of the effective socio-economic costs,
different factors must be considered, such as direct and indirect costs. A more
sophisticated approach is needed: it would be useful if costs related to
allergic asthma and rhinitis were included in all statistics from health
providers. Antiallergic drugs should be evaluated in terms of both short- and
long-term benefits on symptoms and also with respect to the improvement of the
individual quality of life and long-term reduction of direct and indirect
costs.
At the moment, in Europe allergic patients are
underestimated, improperly diagnosed and undertreated. Major efforts are needed
to redress this situation: at first by generating additional expenditure for
health care systems but then reducing the cost of the allergenic care to
society as a whole.
The total cost of care for asthma amounts to €17.7 billion
. As a chronic disease which is often difficult to control, asthma is
responsible for significant work impairment and more than a half of the cost
imposed by the disease on society is represented by lost work days (indirect
costs amounting to €9.8 billion) (Lung Health in Europe Facts & Figures,
2003 ERJ). The burden of asthma care in Europe is consistent and the direct
costs are related to outpatient and ambulatory care (€ 3.8 billion), drugs (€
3.6 billion) and inpatient care (€ 0.5 billion) (Lung Health in Europe, 2003).
In a review of nine studies carried out in different
countries, Barnes et al, (Barnes et al, 1996) provided an estimation of the
proportion of direct costs of asthma care. The average physician costs were 22%
(of which 75% related to general practitioner consultations and 25% to
specialist visits). Drug costs make up 37% of the total direct cost of asthma;
hospital costs were 20-25%: inpatient cost were the major component (70-85%),
whilst emergency room treatment was 14-18%. Nevertheless, in different Countries,
such as in the Czech Republic, the number of
hospitalizations for asthma symptoms seems to have decreased from 1995 until 2005
(-52%) (Tuberkulóza a respirační nemoci 2005; http://www.uzis.cz/). All these data underline the importance of nowadays
available medical tools (educational programs, environmental prophylaxis,
maintenance therapy etc.) for preventing heavier socio-economical costs in the
future.
A study on burden of COPD and asthma was performed in the
city of Dubrovnik during 2002-2006. Asthma patients (4121) were treated in
hospital for 1 192 days during a five-year period. Total cost was 90 771 Euro.
Average length of stay in hospital was 9.85 days and the cost of treatment per
patient was 750.18 Euro (Vrbica, 2007). It was found that all analysed
parameters (number of patients, length of stay, cost of treatment) was higher
for COPD than for asthma.
