To investigate the clinical severity of severe acute respiratory syndrome coronavirus 2 infection among children with asthma and determine the risk factors for the decline in lung function tests (LFTs).

Study included asthma patients with coronavirus disease 2019 (COVID-19) infection (n = 187) and without COVID-19 infection (n = 792) who were followed between March 2020 and March 2021 by the Hacettepe University Department of Pediatric Allergy in Ankara, Turkey.

Demographic and clinical features of patients were obtained from medical records. COVID-19 infection severity was classified from mild to severe. LFTs, chest x-ray, and computed tomography images (if performed), treatments and outcomes were obtained from electronic medical records. Patients with COVID-19 infection were either confirmed by testing or probable by clinical history and symptoms. Prepandemic LFTs were evaluated in the control and study groups, and LFTs were also performed in children >5 years of age in the study group at a median of 72 weeks after the COVID-19 infection. All the children and their parents completed the Turkish Childhood Asthma Control Test (4–11 years old) or Asthma Control Test (≥12 years old). Asthma severity was assessed according to the Global Initiative for Asthma 2019 guidelines. Obesity was defined as having a BMI ≥95th percentile for age and sex.

Asthmatic children with COVID-19 were mainly male (57.2%), and the median age was 8.6 years. Atopic sensitization was more common in the COVID-19 group (P = .027). Prematurity (21%) and obesity (21.8%) were the most common comorbid conditions. Of patients, 163 (87.6%) had a mild clinical COVID-19 course and 13 (7%) had moderate disease. There was no significant difference in forced expiratory volume1 (FEV1) %, forced vital capacity (FVC) %, and forced expiratory flow (FEF) 25% to 75% between the control and study patients before COVID-19 infection. In comparing LFTs before and after COVID-19 infection in study patients, no significant differences were found in FEV1%, FVC%, and FEV1/FVC. However, the frequency of patients with moderate asthma increased after COVID-19 infection (34% vs 45%, P < .001). Obesity (odds ratio: 3.785, 95% confidence interval: 1.152–12.429, P = .028) and having a family history of atopy (odds ratio: 3.359, 95% confidence interval: 1.168–9.657, P = .025) were found to be the independent risk factors for ≥25% decrease in FEF25-75 because of COVID-19 infection.

The distribution of COVID-19 severity observed in this study was similar to that of the general population. The majority (95.7%) of asthmatic patients with COVID-19 infection were symptomatic, although most had mild disease. A significant increase in patients classified with moderate asthma after COVID-19 infection was observed among the study subjects. Obesity was found to be a risk factor for ≥25% decrease in FEF25-75.

Although obesity did not appear to impact the severity of COVID-19 infection, this study adds to the body of evidence that obesity can be an independent risk factor on the natural history of asthma, especially on asthma control and severity. The generalizability of this study is limited as it does not take into consideration other asthma-modifying factors specific to other populations. However, this study further highlights that special consideration should be taken in the care of asthmatic children with obesity, and pediatricians and asthma specialists should remain mindful of the possible long-term effects of obesity on asthma.