Real-life asthma impairment: SABA use depends on smoking phenotype

Background : Asthma impairment is defined by short-acting beta-agonist (SABA) use, symptoms, functional limitations, and pulmonary function. Objective measures of impairment rely on SABA records but the Respiratory Effectiveness Group believe SABA use may vary by management step and smoking status. Methods: Real-life study pooling records from the UK’s Optimum Patient Care & Clinical Practice Research Databases for asthma patients aged 16–70yrs. Average daily SABA use was evaluated over one year (total annual dose prescribed/365) and split by management step (inhaled corticosteroid [ICS] initiation or step up) and smoking status (current, non- and ex-smoker). Results: For both ICS initiation and step-up populations, the distribution of SABA dosage varied significantly by smoking status (p<0.001). More current smokers used ≥800µg, and fewer ≤200µg SABA daily than non- or ex-smokers. ICS Initiation*   Smoking status SABA Daily Dosage (µg) Non smoker n(%) Ex-smoker n(%) Current smoker n(%) ≤200 20169 (52.4) 11886 (52.1) 10106 (39.5) 201-800 16288 (42.3) 9713 (42.6) 12643 (49.3) ≥800 2081 (5.4) 1213 (5.3) 2884 (11.3) *p<0.001 (SABA distribution by smoking status) ICS Step-up*   Smoking Status SABA Daily Dosage (µg) Non smoker n(%) Ex-smoker n(%) Current smoker n(%) ≤200 7612 (35.6) 3460 (33.9) 2349 (21.9) 201-800 10836 (50.6) 5200 (51.0) 5529 (51.4) ≥800 2950 (13.8) 1544 (15.1) 2873 (26.7) *p<0.001 (SABA distribution by smoking status) Conclusions: Average SABA use is higher among ICS step-up compared with ICS initiation patients. Current smokers use more SABA than non- or ex-smokers, irrespective of management step. Further work is required to set meaningful SABA thresholds for objective measures of real-life asthma impairment.