Rate and predictors of biologic initiation in patients with severe asthma: a retrospective cohort study

Background: Biologic therapy uptake for poorly controlled severe asthma is suboptimal despite guideline recommendations. Objectives: To evaluate real-world biologic initiation trends and predictors among patients with severe uncontrolled asthma (SUA) and SUA with eosinophilic phenotype (SUA-EP). Design: A retrospective real-world cohort study that used Komodo Health administrative claims to identify US patients with SUA (controller/rescue medication use and ⩾2 asthma exacerbations in a year) and a subgroup of patients with SUA-EP (blood eosinophil count ⩾150 cells/µL in the year pre- or post-exacerbation). Methods: Biologic initiation trends following first asthma exacerbation were assessed, and factors associated with lack of biologic initiation following second exacerbation (SUA-EP only) were identified using LASSO regression models; odds ratios (OR), 95% confidence intervals (CIs), and p -values were calculated using logistic regression. Results: Biologic initiation rates following the first exacerbation were low at 12.7% (4360/34,246) and 12.2% (309/2526) of patients with SUA and SUA-EP, respectively; mean time between second exacerbation and initiation was 13.4 and 11.9 months. Predictors of lack of biologic initiation included young age (12–17 years; OR (95% CI) 3.65 (1.69–7.89)), primary care physician specialty at index relative to respiratory specialist (2.89 (2.04–4.10)), and antibiotic use (2.29 (1.44–3.66); all p < 0.05), indicating that younger patients, those managed by primary care and those treated with antibiotics for exacerbations, were less likely to receive biologics. Biologic initiation was more likely among patients with a cumulative systemic corticosteroid dose ⩾500 mg (prednisone equivalent; 0.38 (0.25–0.57)), those using leukotriene modifiers (0.42 (0.28–0.62)) or single-inhaler triple therapy (0.06 (0.01–0.40)), and those with eosinophilic disorders (0.19 (0.07–0.52); all p < 0.05). Conclusion: Despite eligibility, most patients with SUA and SUA-EP did not receive any biologic; younger age and primary care management were predictors of lack of biologic initiation. This highlights the need for improved specialist referral and biologic uptake.