The use of short-acting-beta-2-agonists (SABA) has been associated with prediction of increased risks of chronic obstructive pulmonary disease (COPD) exacerbations in patients, according to a recent study entitled “Reliever salbutamol use as a measure of exacerbation risk in chronic obstructive pulmonary disease” published in BMC Pulmonary Medicine. The research team, led by Dr. Christine R. Jenkins, MD, MBBS of the department of thoracic medicine in Concord Hospital at University of Sydney in Australia, along with colleagues performed a retrospective study of the effects of the reliever salbutamol (A class of SABA which is commonly prescribed for pulmonary disorders), administered at a standard dose of 90μg among a total of 810 patients with moderate to severe COPD who were enrolled in the trial to compare the efficacy of twice-daily doses of budesonide/formoterol 320/9μg and formoterol 9μg.
The researchers classified the first occurrence of reliever (salbutamol) use as an indicator to predict short-term exacerbation risk of COPD (3 weeks). They categorized the levels of reliever use according to the number of inhalations daily, with more than four inhalations termed as “low,” more than 10 inhalations termed as “moderate” and more than 20 inhalations termed as “high” frequency uses. For long-term analysis, exacerbation risks within a period of 3 to 12 months during the study was used as the time limit, whereas the number of inhalations were categorized as 2 to 5 inhalations daily being “low,” 6 to 9 inhalations daily being “medium” and more than 10 inhalations daily being termed as “high” usage.
In the short-term analysis, 692 patients reached the low threshold of reliever use, 351 patients reached the medium threshold and 91 patients reached the high threshold. In the long-term analysis, 234 patients reached the low threshold of use, 155 patients reached the medium threshold and 92 patients reached the high threshold. It is worth noting that the results were cumulative, referring to the fact that patients reaching the highest threshold were also taken into account with those within the low and medium thresholds as well.
Statistical analysis of data showed that in comparison to the control group of patients, a significantly higher, short-term exacerbation risk within the groups with medium and high frequency reliever use in both budesonide/formoterol-receiving patients as well as formoterol monotherapy-receiving patients. As far as the long-term risks of exacerbations were concerned, patients with high uses of reliever had a 135% increased rate of exacerbations, as compared to 67% in the medium and 21% in the low usage group.
Apart from these findings, among all reliever-use groups, patients taking budesonide/formoterol had lower short-term and long-term exacerbation rates compared to those taking only formoterol.