Age of Asthma Onset Linked to Level of Asthma Control, Comorbid Conditions

Severe and uncontrolled asthma are more common in people who develop asthma later in life, results from a recent metanalysis show.

The results of the study, conducted by Esmé Baan, MD, of the University Medical Center Rotterdam, and colleagues were published in The Journal of Allergy and Clinical Immunology: In Practice.

Investigators used 5 European electronic databases to create a cohort of adult patients with asthma and categorized patients by their age of asthma onset. The categories were childhood-onset asthma, which was defined as asthma onset at less than 18 years old (n=81 691); adult-onset asthma, defined as onset at 18 to 40 years old (n=218 184); and late-onset asthma, defined as onset at 40 years old or later (n=286 561). Of all patients, 7.3% had severe asthma.

Patients with late onset-asthma had significantly more uncontrolled asthma, defined as 2 or more severe asthma exacerbations, than patients with adult-onset asthma (adjusted odds ratio [OR], 2.8; 95% CI, 1.7-4.5; P=.0001). There was significantly more uncontrolled asthma reported in patients with adult-onset asthma than in patients with childhood-onset asthma (adjusted OR, 43.1; 95% CI, 20.6-89.8; P<.0001).

Severe asthma was most common in patients with late-onset asthma (10%), but less common in patients with adult-onset asthma and childhood-onset asthma (5% and 3%, respectively).

Patients with late-onset asthma had significantly higher risks for nasal polyposis (adjusted OR, 1.8; 95% CI, 1.2-2.6; P=.0047), being overweight/obese (adjusted OR, 1.3; 95% CI, 1.2-1.4; P<.0001), diabetes (adjusted OR, 2.3; 95% CI, 1.8-2.9; P<.0001), and gastroesophageal reflux disease (adjusted OR, 1.4; 95% CI, 1.2-1.7; P=.0001) than patients with adult-onset asthma.

Adult-onset asthma was associated with a significantly higher risk of being overweight/obese than childhood-onset asthma (adjusted OR, 1.4; 95% CI, 1.1-1.8; P=.0090). However, adult-onset asthma was also associated with lower risk for atopic disorders than childhood-onset asthma (adjusted OR, 0.8; 95% CI, 0.7-0.95; P=.0084).

Limitations of the analysis include the potential misclassification in databases of patient age of asthma onset as well as potential miscoding in databases of comorbid conditions. The design of the study does not allow for inference of directional effects, meaning that “overweight/obesity can be both a risk factor for asthma development as well as an asthma-associated comorbidity,” the authors wrote.

“This, however, does not mitigate the relevance of associations between age at onset of asthma and comorbidities we report because awareness is relevant on both the policy-making and the patient care levels,” investigators said.

The results have clinical implications, as the data shows patient characteristics and comorbidities vary by the age of asthma onset.

“In conclusion, this international multi-database cohort study demonstrates consistent differences in asthma-related comorbidities, asthma control (ie, exacerbation rates), and severity of asthma between childhood-onset, adult-onset, and late-onset phenotypes of adult asthmatics,” the investigators wrote. “Further research on the pathophysiological basis of these differences might give better insights into the clinical utility of these phenotypes toward personalized asthma management.”

Baan EJ, de Roos EW, Engelkes M, et al. Characterization of asthma by age of onset: a multi-database cohort study. J Allergy Clin Immunol Pract. 2022;10(7):1825-1834.e8. doi:10.1016/j.jaip.2022.03.019