MONTREAL, May 4, 2021 – For a long time, the progression of asthma in children was believed to be predetermined and inescapable. However, the results of scientific work carried out at CHU Sainte-Justine and the Université de Montréal published today in the European Respiratory Journal suggest that early and sustained control of this condition can increase the chances of remission, and possibly lead to a complete cure.

The symptoms of asthma in young children disappear in about 50-60% of cases by school age. However, many children already have an irreversible decrease in lung function by the age of 6, which can interfere with normal lung growth and increase the risk of developing chronic obstructive pulmonary disease in adulthood.

"Our study suggests a window of opportunity to increase the likelihood of remission and the chances of changing the course of the disease," points out Cristina Longo, PhD, first author of the study.

"Compared to children in whom asthma control is rapid and sustained, children whose asthma has not been treated, that is to say, whose symptoms and attacks remain poorly controlled within two years of diagnosis, have a substantially reduced probability of remission," says Dr. Francine Ducharme, pediatric epidemiologist and researcher at CHU Sainte-Justine and professor in the Department of Pediatrics at the Université de Montréal.

The need for rapid and sustained control

The persistence of asthma beyond infancy has been associated with several non-modifiable risk factors such as sex, acquired allergies, and parental history. But it has also been associated with modifiable factors such as the frequency and severity of attacks, which has raised the following question among researchers: By preventing attacks and managing asthma early, could we increase the chances of remission?

The current study shows that within two years of diagnosis, the level of asthma control is a significant determinant of the likelihood of remission.

"Specifically, children who experienced very poor disease management throughout the two years after diagnosis had their potential for remission reduced by 52%, while those who had poor disease management at the beginning but achieved good management by the end of the first two years had only an 11% reduced chance of remission," says Cristina Longo.

"The dynamic aspect of this observation is very exciting because it implies more than a simple genetic predisposition," adds Lucie Blais, PhD in the Department of Pharmacology at the Université de Montréal. "This suggests a window of opportunity early after diagnosis to change the course of the disease." 

To arrive at their conclusion, the research team gathered a cohort of 48,687 Canadian children born between 1990 and 2013 who were diagnosed with asthma before age 5. The researchers assessed the trajectory of disease control during the two years following diagnosis and then monitored the course of their disease. A child was considered in remission after two years with no medication, no medical or emergency room visits, and no asthma-related hospitalizations.

"These findings indicate that we need to focus our clinical and research efforts on this important time in early childhood when lung growth is most important. A shift in the tenets of medical practice is critical," says Dr. Ducharme.

Managing the disease at all costs

For over 30 years, the therapeutic approach for toddlers has been debated. Should we simply treat the crises or prevent them?

Use of preventive treatments and research efforts were mostly focused on children with risk factors (parental asthma and childhood allergies) and still having asthma at age 6. Symptom relief and treatment of asthma attacks were assumed to be sufficient for other children since they seemed to recover from their asthma anyway. 

In 2015, the joint recommendations of the Canadian Thoracic Society and the Canadian Paediatric Society on the diagnosis and management of asthma in preschoolers led by Dr. Ducharme proposed abandoning this approach and instead aiming for disease management for all, with preventive treatment personalized by level of control.

Due to a lack of access to pulmonary function tests specific to preschoolers and a lack of sound scientific data on the optimal time to initiate preventive treatment, health care professionals were still hesitant to identify which child should receive preventive treatment and when to initiate it. But, while recommended, many parents are reluctant to continue daily treatment following an asthma attack that appears to have resolved.

The study cited here confirms that to improve the chances of remission, health care professionals and parents need to work together to achieve rapid and long-lasting control of asthma, starting with the first attack in toddlers.

Improving the quality of life for very young children

Asthma is the most common chronic disease in children; it has an especially important effect on preschoolers. They have rates of emergency room visits two to three times higher than all other age groups.

The research team is now looking at promising approaches to improve asthma control in this age group.

"We are examining the usefulness of toddler-specific pulmonary function tests or early recognition of children with asymptomatic bronchial obstruction, testing innovative interventions to prevent cold-triggered asthma attacks, and examining the long-term impact of disease control drugs such as inhaled corticosteroids on preventing lung sequelae and increasing the chances of remission," concludes Dr. Ducharme.

About the study

The article "A[Q1]ssociation between asthma control trajectories in preschoolers and disease remission" was published in the European Respiratory Journal in May 2021. The first author is Cristina Longo, PhD. The principal author is Dr. Francine M. Ducharme, pediatric epidemiologist and researcher at CHU Sainte-Justine and professor in the Department of Pediatrics at the Université de Montréal.

This study was conducted in collaboration with researchers from four Canadian provinces: Mohsen Sadatsafavi, PhD, University of British Columbia, Marni Brownell, PhD, University of Manitoba, Jacqueline M. Quail, PhD, Saskatchewan Health Quality Council, and Lucie Blais, PhD, Université de Montréal.  

The study was funded by the Canadian Respiratory Research Network (CRRN). This network is funded by the Canadian Institutes of Health Research and partners.