Differences Between Early- and Late-Onset Asthma: Role of Comorbidities in Symptom Control.

Background: Asthma can present in early childhood or de novo in adulthood. Our understanding of the burden of comorbidities in adult asthmatic patients stratified by age at onset is incomplete.

Objectives: To evaluate how different comorbidities may affect symptom control in two distinct groups of patients with early- and late-onset asthma (EOA and LOA, respectively) and to explore whether reported comorbidities are associated with lung function and inflammatory parameters.

Methods: We conducted a cross-sectional study of 175 adult asthmatic patients (aged 57.5 ± 17.1 years) recruited at our university asthma clinic. We defined EOA as asthma onset less than 12 years, and LOA as onset greater than 40 years. The primary outcome was symptom control and main comorbidities evaluated were rhinitis, gastroesophageal reflux, obesity, cardiovascular conditions, and bronchiectasis. We used multivariable regression analysis to identify potential predictors of poor control in EOA and LOA.

Results: Of 175 subjects, 77 had EOA (44%), 98 had LOA (56%), and comorbidities had a differential impact in the two groups. Rhinitis was more frequent in EOA (76 vs 53%; P = .02) and was associated with uncontrolled asthma (P < .001), reduced FEV/FVC (P = .01), increased eosinophils (P = .003) and total IgE (P < .01). Conversely, in LOA, rhinitis was associated with more controlled asthma and higher FEV/FVC (both P < .01). In EOA, only, IgE levels were directly related to blood eosinophils (r = 0.42; P <.001) and inversely to FEV/FVC (r = -0.35; P = .002). Obesity was present in 20% of patients in both groups, but only in LOA was it associated with uncontrolled disease (P = .009), reduced FEV/FVC (P = .009), and blood neutrophils (P = .03). In multivariable regression analysis, rhinitis in EOA and obesity in LOA were the risk factors most closely associated with poor control. Gastroesophageal reflux, cardiovascular comorbidities, and bronchiectasis did not affect control.

Conclusions: Early-onset persistent asthma and late-onset asthma are distinct phenotypes with different underlying inflammatory patterns and different comorbidities affecting symptom control.