Study Reveals Relationship Between Peak Expiratory Flow Changes and Asthma Exacerbations in Children

Researchers uncovered a crucial early warning sign for pediatric asthma exacerbations: children with asthma exhibited a decline in PEF approximately 1.34 days before the onset of symptoms. Upper respiratory tract infections emerged as the primary trigger for acute asthma exacerbations, and air pollution exhibited a significantly higher impact on PEF variation versus other factors.

Asthma, a chronic respiratory condition characterized by airway inflammation and hyperresponsiveness, affects millions of children worldwide, posing a significant burden on both patients and healthcare systems. Asthma exacerbations, marked by sudden worsening of symptoms, represent a major concern due to their potential to escalate into severe respiratory distress and hospitalization.

In patients with poor perception, identifying acute asthma exacerbations by clinical asthma score, asthma control test, or asthma control questionnaire is difficult. Considering this, Kunling Shen, Department of Respiratory, Shenzhen Children Hospital, Shenzhen, China, and colleagues aimed to analyze whether children with asthma have changes in peak expiratory flow before an acute asthma exacerbation. They also evaluated the relationship between PEF and asthma exacerbation.

For this purpose, the researchers collected basic information (including age, sex, atopy, etc.) and clinical information of asthmatic children who registered in the Electronic China Children’s Asthma Action Plan (e-CCAAP) from 2017 to 2021. Subjects with fourteen consecutive days of PEF measurements were eligible. The study subjects were categorized into an exacerbation group and a control group. They analyzed the relationship between changes in PEF% pred and asthma symptoms.

The study included 194 children with asthma who met the inclusion criteria, including 74.2% males and 25.8% females, with a male-to-female ratio of 2.88:1. The subjects' mean age was 9.51 ± 2.5 years.

The researchers reported the following findings:

• There were no significant differences in sex, age, allergy history, or baseline PEF between the two groups.
• There was no significant difference between the variation in PEF at 14 days in children with and without a history of allergy.
• Patients who only had a reduction in PEF but no symptoms of asthma exacerbation had the greatest decrease in PEF compared to the other groups.
• The most common cause of acute exacerbations of asthma is upper respiratory tract infection.
• Among the causes of acute exacerbations of asthma, the variation in PEF caused by air pollution was significantly higher than that of other causes.
• In acute exacerbations, the decrease in PEF was significantly greater in the exacerbation group than in the control group.
• In children with asthma symptoms, there was a decrease in PEF approximately 1.34 days before the onset of the symptoms.

The findings revealed that children with asthma show a decrease in PEF 1.34 days before the onset of asthma symptoms.

"We recommend that asthmatic children who show PEF reduction should step up asthma therapy," the researchers wrote. "The most common cause of asthma' acute exacerbations was upper respiratory tract infections, and PEF variation caused by air pollution was significantly higher than that caused by other factors."

Reference:

Chen, X., Han, P., Kong, Y. et al. The relationship between changes in peak expiratory flow and asthma exacerbations in asthmatic children. BMC Pediatr 24, 284 (2024). https://doi.org/10.1186/s12887-024-04754-7