Effectiveness of inhaled corticosteroid for adults with chronic asthma

Aim: To evaluate the asthma outcomes (symptom control and exacerbation) on the various types of ICS treatment (beclomethasone, budesonide and fluticasone). Methods: This was a retrospective cohort study with data retrieved between 2018-2019 from SingHealth Polyclinics (SHP) database. The patients had to have at least two Asthma control Test (ACT) score, and using the same medication, inhaler type, and dose range for one year from the index visit within the study period. Asthma control test score and exacerbation were used to evaluate treatment outcomes. Asthma exacerbation was defined by: i) Number of rescue therapy (RT); ii) Number of referrals to the Singapore General Hospital (SGH) emergency department (ED) for asthma exacerbation; and iii) Total oral Prednisone dose prescribed in a year. All analysis were carried out using STATA, Python 3.9.7 and R 3.5.2 with Rstudio. Linear regression was performed for continuous outcome variables to obtain unadjusted regression coefficients ( ) with 95% confidence intervals (CI) and p-values. Results: A total of 1,810 patients with asthma on ICS were included in this retrospective cohort study. Majority of patients were on beclomethasone (n=1405, 77.6%), followed by budesonide (n=337, 18.6%) and fluticasone (n=68, 3.8%). Linear regression showed no significant difference in ACT score and Prednisolone dose prescribed among the three groups. 12.6% of patients had at least one RT. Patients on beclomethasone required significantly more RT compared to fluticasone (beclomethasone: 13.5%, budesonide: 10.7%, fluticasone: 4.4%, p=0.045). 7.2% of patients had at least one referral to the ED, and patients on fluticasone required approximately 2.5 times more referrals compared to beclomethasone and budesonide, which was statistically significant (beclomethasone: 7.0%, budesonide: 6.2%, fluticasone: 16.2%, p=0.012). Conclusion: Patients on Beclomethasone had significantly higher number of RT, but those on fluticasone had more ED referrals, suggesting more severe exacerbations requiring care in the tertiary setting.