TRENDS IN HOSPITALIZATION TRENDS IN HOSPITALIZATION RATES FROM ASTHMA RATES FROM ASTHMA

IN CHILDREN AND ADOLESCENTS IN CHILDREN AND ADOLESCENTS IN POLANDIN POLAND

Krystyna SzafraniecKrystyna Szafraniec11, Wieslaw Jedrychowski, Wieslaw Jedrychowski11, , Bogdan WojtyniakBogdan Wojtyniak22 and Pawel Gorynski and Pawel Gorynski22

11Chair of Epidemiology and Preventive Medicine, Jagiellonian Chair of Epidemiology and Preventive Medicine, Jagiellonian University, Krakow, PolandUniversity, Krakow, Poland22 Department of Medical Statistics, National Institute of Hygiene, Department of Medical Statistics, National Institute of Hygiene, Warsaw, PolandWarsaw, Poland

Background

Asthma is considered as an allergic inflammation of Asthma is considered as an allergic inflammation of airways, which causes bronchial obstruction. airways, which causes bronchial obstruction.

Nowadays, asthma is one of the common chronic Nowadays, asthma is one of the common chronic disease in industrialised countries and its prevalence disease in industrialised countries and its prevalence has increased worldwide over the last thirty years. has increased worldwide over the last thirty years.

Its prevalence varies markedly across the regions, Its prevalence varies markedly across the regions, possible risk factors have been identified that may possible risk factors have been identified that may explain the differences in asthma prevalence across explain the differences in asthma prevalence across countries or its rising trends.countries or its rising trends.

BackgroundOf the already recognized risk factors for asthma the Of the already recognized risk factors for asthma the strongest are a parental history of asthma and strongest are a parental history of asthma and occurrence of other atopic diseases such as hay fever occurrence of other atopic diseases such as hay fever and eczema.and eczema.

The environmental factors include indoor allergens, The environmental factors include indoor allergens, environmental tobacco smoke, and possible changes environmental tobacco smoke, and possible changes in housing, diet and life style.in housing, diet and life style.

There has been long debate about the possible role of There has been long debate about the possible role of ambient air pollution as a cause of increase in asthma. ambient air pollution as a cause of increase in asthma. The evidence relating air pollution to asthmatic The evidence relating air pollution to asthmatic symptoms is still weak and inconsistent.symptoms is still weak and inconsistent.

BackgroundThough geographical trends of asthma in the world are Though geographical trends of asthma in the world are clearly variable, numerous countries, independently of clearly variable, numerous countries, independently of their economic status, have confirmed increasing their economic status, have confirmed increasing prevalence of childhood asthma.prevalence of childhood asthma.

The increase The increase began in the began in the 1970s and the 1970s and the range of increase range of increase doubled at least. doubled at least.

Changes in prevalence of asthma ever diagnosed in children and young adults

Aims of the study

• To assess the time trends in hospitalization rates To assess the time trends in hospitalization rates from asthma in children and adolescents below 19 from asthma in children and adolescents below 19 years of age for the last 15 years in Polandyears of age for the last 15 years in Poland

• Analyse geographical variation in hospitalization Analyse geographical variation in hospitalization from asthma within the countryfrom asthma within the country

Material and Methods

• Data from individual hospital records were used Data from individual hospital records were used to recognize the cause of hospitalizationto recognize the cause of hospitalization

• Morbidity ratios in 5-year age groups from asthma Morbidity ratios in 5-year age groups from asthma for years 1986-1999 were calculatedfor years 1986-1999 were calculated

• Linear regression method was applied to examine Linear regression method was applied to examine trends over timetrends over time

ResultsHospitalization rates from asthma in children and adolescents below 19 Hospitalization rates from asthma in children and adolescents below 19 years of age years of age showed a consistent rising trends. In the period 1984-1996 showed a consistent rising trends. In the period 1984-1996 the rates doubled for both genders.the rates doubled for both genders.

• Time trends were highly Time trends were highly linear (p<0.001, Rlinear (p<0.001, R22=0.94).=0.94).

• Hospitalization rates Hospitalization rates estimated by the regression estimated by the regression analysis were 1.6-times analysis were 1.6-times higher for boys than girls.higher for boys than girls.

• Mean annual increase was Mean annual increase was 12.2% for boys and 10.6% 12.2% for boys and 10.6% for girls.for girls.

ResultsTrends in hospitalization rates due to childhood asthma by age groupsTrends in hospitalization rates due to childhood asthma by age groups

• The most steep The most steep increase occurred in increase occurred in the children under 4 the children under 4 years of age years of age (annually: 20.3% for (annually: 20.3% for boys and 18.9% for boys and 18.9% for girls).girls).

• In the age groups In the age groups 5-9 yrs and 10-14 yrs 5-9 yrs and 10-14 yrs mean annual gender-mean annual gender-related increase range related increase range from 10.5 - 14.1%.from 10.5 - 14.1%.

GirlsBoys

GirlsBoys

ResultsTrends in hospitalization rates due to childhood asthma by age groupsTrends in hospitalization rates due to childhood asthma by age groups

• The slowest increase The slowest increase was in the oldest age was in the oldest age group (3.7% annually), group (3.7% annually), however, linear trend in however, linear trend in this group was this group was statistically significant statistically significant (p<0.001).(p<0.001).

• Only in the oldest age Only in the oldest age group the differences in group the differences in the rates were not gender-the rates were not gender-related. related.

GirlsBoys

GirlsBoys

Results

161 - 290121 - 160 90 - 120missing

Hosp. rate / 100 000

Geographical distribution of hospitalization rates due to asthma in Geographical distribution of hospitalization rates due to asthma in 1999 by provinces 1999 by provinces was significantly variable compared with the was significantly variable compared with the average country rate.average country rate.

The highest overall rates in the The highest overall rates in the northern part of Poland were northern part of Poland were observed. They were almost twice observed. They were almost twice as high as the average country rate as high as the average country rate of 145/100 000.of 145/100 000.

This trend remained stable for all This trend remained stable for all age groups except for the children age groups except for the children 14-19.14-19.

The lowest hospitalization rates, The lowest hospitalization rates, representing 60-75% of country representing 60-75% of country average were noted for the north-average were noted for the north-west provinces. west provinces.

Summary• The results show that hospitalization rates for children with The results show that hospitalization rates for children with asthma in Poland reflect linear increase over the last several asthma in Poland reflect linear increase over the last several years.years.

• The tendency was typical for the youngest age groups.The tendency was typical for the youngest age groups.

• Though hospitalization rates were significantly lower in Though hospitalization rates were significantly lower in girls than boys for each age group, the time trends in both girls than boys for each age group, the time trends in both groups increased similarly.groups increased similarly.

• The geographical variability of the hospitalization rates due The geographical variability of the hospitalization rates due to asthma in Poland is not compatible with the hygienic to asthma in Poland is not compatible with the hygienic hypothesis of asthma and allergic diseases. hypothesis of asthma and allergic diseases.