TABLE 1

Summary of the association between short-acting β₂-agonist (SABA) overuse (three or more SABA canisters per year compared with fewer than three canisters per year) and exacerbations in a selection of SABA in Asthma (SABINA) programme studies

First author [ref.]	Country	Population size (n)	Prevalence of SABA overuse (% patients)	Association between SABA overuse and asthma exacerbations
Noorduyn [8]	Canada	115 478		SABA overuse was associated with an increased mean±sd exacerbation rate
	Alberta	107 444	28.0	0.31±0.86 versus 0.17±0.62
	Nova Scotia	8034	39.4	0.46±1.11 versus 0.3±1.36
Nwaru [14]	Sweden	365 324	30	Positive association observed between number of SABA cannisters issued and exacerbation risk (hazard ratio (95% CI)) ≤2 cannisters: 1.00
				3–5 cannisters: 1.26 (1.24–1.28)
				6–10 cannisters: 1.44 (1.41–1.46) ≥11 cannisters: 1.77 (1.72–1.83)
Bloom [12]	UK	574 913	38	SABA overuse was associated with increased risk of exacerbation across asthma severities(adjusted hazard ratio (95% CI)) BTS steps 1 and 2: 1.2 (1.16–1.24) BTS steps 3–5: 1.24 (1.20–1.28)
Bateman [10]	Multicountry	8351	38	SABA overuse was associated with increased exacerbation incidence (adjusted incidence rate ratio (95% CI)) 3–5 cannisters: 1.40 (1.24–1.58) 6–9 cannisters: 1.52 (1.33–1.74) 10–12 cannisters: 1.78 (1.57–2.02) ≥13 cannisters: 1.92 (1.61–2.29)

BTS: British Thoracic Society.