SABA may be overprescribed for asthma in SG

In Singapore, short-acting β2-agonist (SABA) is often overused for asthma, especially in the specialist care setting, according to data from the SABINA III study.

Real-world asthma management practices in the Singapore cohort showed that SABA was overprescribed (≥3 canisters per year) in 17 percent of all patients. This overprescription was more common with specialists (26 percent) than primary care physicians (6 percent). [BMJ Open 2024;14:e064245]

“While almost all patients were prescribed inhaled corticosteroids (ICS) or ICS/long-acting β₂ agonist (LABA) fixed-dose combinations, among those prescribed SABA relievers on a background of maintenance therapy, SABA overprescription was widespread, occurring in over 40.5 percent of patients, with a similar pattern of greater overprescription in specialist vs primary care,” the investigators noted.

Factors affecting SABA use

Compared with patients who received prescriptions of 0–2 SABA canisters in the past 12 months, those who received prescriptions of ≥3 SABA canisters were more likely to have uncontrolled asthma (42.9 percent vs 17.6 percent) and require more intensive treatment regimens (GINA step 4/5: 80.0 percent vs 50.0 percent).

Of note, specialists treated a higher proportion of patients with moderate-to-severe asthma compared with primary care physicians. This difference in patient population might explain the observed higher rates of SABA overprescription by specialists, according to the investigators, adding that complex asthma cases managed by specialists could have underlying characteristics that make patients more prone to overreliance on SABA inhalers.

“Alternatively, it may, in part, be the result of better management of asthma at the primary care level, spearheaded by the Singapore National Asthma Programme (SNAP), emphasizing the important role that primary care providers play in asthma care,” they said.

Risk of excessive SABA use

SABA overprescription was associated with an increased risk of severe exacerbations and increased odds of poorly controlled asthma in the Pan International SABINA III study. Several other studies also showed evidence of a link between overreliance on SABA and an increased risk of preventable exacerbations even in mild asthma. [Eur Respir J 2022;59:2101402; Adv Ther 2020;37:4190-4208; Eur Respir J 2020;55:1901872]

“Thus, patients being overprescribed SABA in Singapore may be at risk of poor clinical outcomes. Taken together, these data reveal that while the primary healthcare system fares better than specialist care in SABA prescription practices, there is a need for improvement across prescriber types in the country,” the investigators said.

The Singapore cohort of SABINA III comprised 205 patients (mean age 53.6 years, 62 percent female) with asthma, among whom 55.9 percent were enrolled by specialists and 44.1 percent by primary care physicians. Most of the patients (80.5 percent) had moderate-to-severe asthma (86.0 percent in specialist care and 74.4 percent in primary care), and 78.0 percent had well or partly controlled disease. In the 12 months before study enrolment, 18.0 percent of patients experienced ≥1 severe exacerbation.