Abstract Rationale Asthma management guidelines emphasise early initiation of inhaled corticosteroids (ICS) and regular therapy adjustments based on control status. However, guideline adherence in routine clinical practice remains underexplored in Asian populations. We examined real-world prescribing patterns of ICS initiation and step-up/step-down adjustments in Singapore. Methods We conducted a retrospective study using the SingHealth COPD and Asthma Data Mart, an integrated database encompassing primary and secondary care encounters from 2015-2019. Asthma-related visits included outpatient, emergency department (ED), or inpatient encounters coded with a physician-diagnosed asthma diagnosis. To allow a one-year baseline period, only visits occurring after 2016 were included as index visits. Appropriate ICS initiation was defined as an ICS prescription during a visit requiring systemic corticosteroids. Appropriate step-change was defined as: (1) step-up after a preceding event, or (2) step-down after ≥3 months without events. Next-visit asthma events (ED visits or hospitalisations requiring systemic corticosteroids) were compared across therapy-change categories. Results A total of 64,670 asthma-related visits involving 15,363 patients were analysed. Among 20,150 index visits, 7,084 (35.2%) included an inhaled corticosteroid (ICS) prescription. ICS initiation was lowest in ED (9.4%) and highest in primary care (30.1%), where 41.8% of prescriptions were for high-strength ICS. Among 29,239 eligible follow-up visits, 25,604 (87.6%) showed no change in controller therapy. Of 315 event-related visits, 78.7% lacked an appropriate controller step-up despite a recent exacerbation. Conversely, among 20,830 stable visits, only 1,647 (7.9%) received an appropriate step-down, while 19,183 continued unchanged therapy despite absence of preceding event. Next-visit events were most frequent in visits with an inappropriate absence of step-up and those with an appropriate step-up (23% vs. 21%; OR = 1.10, 95% CI 0.48-2.29), with both groups showing similar median numbers of preceding events (1.1-1.3). In contrast, visits with an appropriate step-down had comparable next-visit event rates to unchanged stable therapy (1.6% vs. 1.8%; OR = 0.87, 95% CI 0.58-1.30), indicating no increased exacerbation risk. ICS exposure analysis showed actual ICS savings from existing step-downs totaling 82.5 million µg beclomethasone dipropionate (BDP)-equivalent, while the potential reduction if all eligible stable visits underwent appropriate step-down was estimated at ∼1.29 billion µg BDP-equivalent to sparing approximately 15-fold the current ICS volume used for step-downs. Conclusions Despite consistent guideline recommendations, both ICS initiation and therapy step-adjustments were infrequently implemented in real-world asthma care. The underuse of step-down therapy represents a major missed opportunity for corticosteroid reduction without added exacerbation risk. This abstract is funded by: GlaxoSmithKline
Toh et al. (Fri,) studied this question.