Asthma management and control in children, adolescents, and adults in 25 countries: a Global Asthma Network Phase I cross-sectional study

BACKGROUND

Asthma is one of the most common non-communicable diseases globally. This study aimed to assess asthma medicine use, management plan availability, and disease control in childhood, adolescence, and adulthood across different country settings.

METHODS

We used data from the Global Asthma Network Phase I cross-sectional epidemiological study (2015-20). A validated, written questionnaire was distributed via schools to three age groups (children, 6-7 years; adolescents, 13-14 years; and adults, ≥19 years). Eligible adults were the parents or guardians of children and adolescents included in the surveys. In individuals with asthma diagnosed by a doctor, we collated responses on past-year asthma medicines use (type of inhaled or oral medicine, and frequency of use). Questions on asthma symptoms and health visits were used to define past-year symptom severity and extent of asthma control. Income categories for countries based on gross national income per capita followed the 2020 World Bank classification. Proportions (and 95% CI clustered by centre) were used to describe results. Generalised structural equation multilevel models were used to assess factors associated with receiving medicines and having poorly controlled asthma in each age group.

FINDINGS

Overall, 453 473 individuals from 63 centres in 25 countries were included, comprising 101 777 children (6445 [6·3%] with asthma diagnosed by a doctor), 157 784 adolescents (12 532 [7·9%]), and 193 912 adults (6677 [3·4%]). Use of asthma medicines varied by symptom severity and country income category. The most used medicines in the previous year were inhaled short-acting β2 agonists (SABA; range across age groups, 29·3-85·3% participants) and inhaled corticosteroids (12·6-51·9%). The proportion of individuals with severe asthma symptoms not taking inhaled corticosteroids (inhaled corticosteroids alone or with long-acting β2 agonists) was high in all age groups (934 [44·8%] of 2085 children, 2011 [60·1%] of 3345 adolescents, and 1142 [55·5%] of 2058 adults), and was significantly higher in middle-to-low-income countries. Oral SABA and theophylline were used across age groups and country income categories, contrary to current guidelines. Asthma management plans were used by 4049 (62·8%) children, 6694 (53·4%) adolescents, and 3168 (47·4%) adults; and 2840 (44·1%) children, 6942 (55·4%) adolescents, and 4081 (61·1%) adults had well controlled asthma. Independently of country income and asthma severity, having an asthma management plan was significantly associated with the use of any type of inhaled medicine (adjusted odds ratio [OR] 2·75 [95% CI 2·40-3·15] for children; 2·45 [2·25-2·67] for adolescents; and 2·75 [2·38-3·16] for adults) or any type of oral medicine (1·86 [1·63-2·12] for children; 1·53 [1·40-1·68] for adolescents; and 1·78 [1·55-2·04] for adults). Poor asthma control was associated with low country income (lower-middle-income and low-income countries vs high-income countries, adjusted OR 2·33 [95% CI 1·32-4·14] for children; 3·46 [1·83-6·54] for adolescents; and 4·86 [2·55-9·26] for adults).

INTERPRETATION

Asthma management and control is frequently inadequate, particularly in low-resource settings. Strategies should be implemented to improve adherence to asthma treatment guidelines worldwide, with emphasis on access to affordable and quality-assured essential asthma medicines especially in low-income and middle-income countries.

FUNDING

International Union Against Tuberculosis and Lung Disease, Boehringer Ingelheim New Zealand, AstraZeneca, UK National Institute for Health Research, UK Medical Research Council, European Research Council, the Spanish Instituto de Salud Carlos III.

TRANSLATION

For the Spanish translation of the abstract see Supplementary Materials section.

Percent body fat, skinfold thickness or body mass index for defining obesity or overweight, as a risk factor for asthma in schoolchildren: which one to use in epidemiological studies?

None of the epidemiological studies indicating that obesity is a risk factor for asthma in schoolchildren have used the percent body fat (PBF) to define obesity. The present study compares the definition of obesity using body mass index (BMI), PBF and the raw sum of the thickness of four skinfolds (SFT) to evaluate this condition as a risk factor for asthma. All classes of children of the target ages of 6-8 years of all schools in four municipalities of Murcia (Spain) were surveyed. Participation rate was 70.2% and the number of children included in the study was 931. Height, weight and SFT (biceps, triceps, subscapular and suprailiac) were measured according to standard procedures. Current active asthma was defined from several questions of the International Study of Asthma and Allergies in Childhood questionnaire. Obesity was defined using two standard cut-off points for BMI and PBF, and the 85th percentile for BMI, PBF and SFT. The highest quartile of each type of measurement was also compared with the lowest. A multiple logistic regression analysis was made for the various obesity definitions, adjusting for age, asthma in the mother and father and gender. The adjusted odds ratios of having asthma among obese children were different for boys and girls and varied across the different obesity definitions. For the standard cut-off points of BMI they were 1.19 [95% confidence interval (CI) 0.41-3.43] for girls and 2.00 (95% CI 0.97-4.10) for boys; however, for PBF (boys 25%, girls 30%) the corresponding figures were 1.54 (95% CI 0.63-3.73) and 1.20 (95% CI 0.66-2.21). BMI, PBF and SFT showed more consistency between each other when using the other cut-off points. BMI, PBF (except standard cut-off points) and SFT produce relatively comparable results when analysing the interaction between obesity and asthma.

Phadiatop compared to skin-prick test as a tool for diagnosing atopy in epidemiological studies in schoolchildren

The validity of the Phadiatop test as compared to the skin-prick test (SPT) for diagnosing atopy in the epidemiological field has not been studied in schoolchildren. The aim of the present study was to evaluate its validity for classifying schoolchildren 9-12 yr old into atopics and non-atopics. A total of 621 children whose parents authorized both a SPT and a blood extraction from all children participating in the phase II of the International Study of Allergies in Children (ISAAC) in Cartagena (Spain) were included in the analysis. A positive SPT was that with at least a wheal having a maximum diameter of 3 mm, once the negative value had been subtracted. Phadiatop was performed according to the manufacturer instructions. Diagnostic tests using SPT as the gold standard were calculated for the whole group of children and also for those with asthma or rhinoconjunctivitis and for children without any of them. The results of the tests were: sensitivity 85.0% (95% CI 82.2-87.8%), specificity 85.5% (95%CI 82.7-88.3%), positive predictive value 72.7% (95%CI 69.0-76.1%), negative predictive value 92.7% (95%CI 90.6-94.7%) and accuracy 85.3% (95%CI 82.3-88.0%). The results improved among the symptomatic groups. Phadiatop can be used as a valid alternative to SPT in the epidemiological setting to diagnose atopy.

Antibody levels to Bordetella pertussis in 10-yr-old children with atopy and atopic asthma

Suboptimal immune responses to vaccination have been suggested among atopic infants. The aim of this study was to assess the influence of atopy and atopic asthma on the humoral response to Bordetella pertussis vaccination. Immunoglobulin (Ig)G and IgA specific antibodies were measured by enzyme linked-immunosorbent assay in 102, 10-yr-old atopic children (66 of them also being asthmatics) and compared with 76 non-atopic and 53 non-atopic non-asthmatic controls of similar age. The levels of antibodies and the percentage of positives to B. pertussis were comparable in all groups. Children with a very high total serum immunoglobulin (Ig)E (Percentile (Pct) > 90th) showed higher (p = 0.01) IgG pertussis antibodies than children with very low serum IgE (Pct < 10th). In conclusion, we found normal pertussis antibody levels in atopic and in atopic asthmatic children in late childhood, thus overriding any possible suboptimal response during infancy.