O1.1.1 Short-acting beta2-agonists (SABA)

Regular short-acting beta2-agonists improve lung function and daily breathlessness scores. A systematic review of randomised controlled trials (Ram 2003) found a significant increase in post-bronchodilator spirometry when compared to placebo; weighted mean difference = 140mls (95% CI 40 to 250) for FEV1 and 300mls (95% CI 20 to 580) for FVC. There were also improvements in post-bronchodilator morning and evening PEF: weighted mean difference = 29.17 l/min (95% CI 0.25 to 58.09) for morning and 36.75 l/min (95% CI 2.57 to 70.94) for evening measurements. The relative risk of dropping out of the study was 0.49 (95% CI 0.33 to 0.73), giving a number needed to treat of 5 (95% CI 4 to 10) to prevent one treatment failure. There was no significant benefit on functional capacity, measured by walking tests, or symptoms other than breathlessness, although one randomised controlled trial has found a significant improvement in six-minute walking distance and quality of life (Guyatt 1987). Short-acting beta2-agonists are now usually prescribed for use as “rescue” medication, i.e. for relief of breathlessness, rather than for regular use.