Does early-onset difficult asthma in adulthood differ by sex? Findings from WATCH.

Background: Whether the nature of early-onset difficult adult asthma differs by sex remains unclear. Aim: To assess clinical characteristics of early-onset difficult asthma in adulthood stratified by sex. Method: The Wessex AsThma CoHort of difficult asthma (WATCH) at University Hospital Southampton (UHS) UK has enrolled 380 patients from the UHS tertiary difficult asthma clinics. We compared clinical characteristics between sexes in patients with early-onset difficult asthma (age of diagnosis ≤18 years). Results: 190 patients had early-onset difficult asthma; 72.1% female (F) and 27.9% male (M). Median age of diagnosis (F vs M) was 5.0 yrs v 3.0 yrs (p=0.033) with a disease duration of 30.0 yrs v 41.5 yrs (p=0.047). Significant differences in comorbidities (F vs M) existed for salicylate sensitivity (29.9% v 8.0% p=0.002), depression (49.6% v 23.8% p=0.004) and bronchiectasis (7.4% v 21.6% p=0.006). No significant differences were seen for atopy, rhinitis, GORD, obesity, other functional comorbidities (dysfunctional breathing, vocal cord dysfunction and anxiety) or healthcare utilisation. F had a higher prevalence for maintenance oral steroids use (41.6% v 24.5% p=0.029). M showed significantly greater airflow obstruction (M vs F); FEV1 67.9% pred. v 81.7%, FEV1/FVC 62.1% pred. v 71.8% and FEF25-75 35.9% pred. v 56.8% (p<0.001), and higher smoking prevalence (52.8% v 36.5% p=0.040). Conclusion: Early-onset difficult asthma in adulthood was predominantly female, but showed different features by sex. Females had higher prevalence of depression, salicylate sensitivity and steroid dependency, while males were diagnosed earlier, had higher smoking prevalence, worse lung function and associated bronchiectasis