In patients with asthma and persistent cold airway hyperresponsiveness, long-term ICS/LABA therapy improves lung function and asthma control but does not reduce the airway response to cold. Moreover, the impact of the ICS/LABA therapy is not affected by whether or not the patient smokes. These were among findings of a Russian study presented at the American Thoracic Society (ATS) International Conference 2022, held in San Francisco, CA, May 13 to 18.
Researchers for the current study sought to study patients with asthma and persistent cold airway hyperresponsiveness, both those who smoked and those who did not smoke, with the goal of determining the effect of ICS/LABA therapy in these patients. The researchers enrolled 84 patients with asthma between the ages of 23 and 42 years who had persistent cold airway hyperresponsiveness and assigned them to 2 groups. Group 1 included 44 smokers with a smoking history between 2 and 11.5 years. Group 2 consisted of 40 nonsmokers. Asthma control was evaluated using the Asthma Control Test (ACT). Lung function was measured as forced expiratory volume in the first second of expiration (FEV1, % predicted) before and as change in FEV1, % predicted, after participants were exposed to 3-minute isocapnic hyperventilation with cold air (IHCA, -20°C). The tests were repeated after 6 and 12 months of ICS/LABA treatment.
At first, patients in groups 1 and 2 showed no significant differences in ACT scores (14.9 ± 0.8 vs 14.6 ± 0.8 points), FEV1 (86.6 ± 2.4 vs 89.2 ± 2.7%), and change FEV1 (-19.1 ± 1.3 vs -19.4 ± 2.4 %, respectively; P >.05). After 6 months, however, group 1 patients displayed a significant increase in ACT scores, to 17.9 ± 1.1 points (P <.05) and an elevation in FEV1 to 99.6 ± 3.2% (P <.01). The airway response to IHCA stayed high (change FEV1 = -19.3 ± 2.9%). After 12 months, ACT scores in group 1 averaged 19.8 ± 1.1 points (P < .001), FEV1 was 91.0 ± 3.3%, and FEV1 equaled -16.7 ± 2.1%.
The researchers saw significant improvement in group 2 patients after 12 months. Whereas ACT scores after 6 months equaled 15.9 ± 1.6 points, after 12 months they rose to 18.6 ± 1.7 points (P <.05). At 6 and 12 months, FEV1 was 95.4 ± 2.4 and 95.6 ± 3.8%, respectively (P >.05).
The airway response to IHCA did not shift significantly: FEV1 after 6 months was -17.3 ± 1.9% and after 12 months, -18.6 ± 3.8% (P >.05). In group 1, a correlation was noted between ACT score and FEV1 (bivariable coefficient of determination (r) = 0.35; P <.05) and between the smoking index and the Tiffeneau Index (FEV1/forced vital capacity [FVC], % predicted; r = -0.39; P <.001). In group 2, ACT scores correlated with FEV1/FVC, % predicted (r = 0.40; P <.05).
The researchers concluded that “Long-term ICS/LABA controller therapy in smokers and nonsmokers with asthma and with persistent cold airway hyperresponsiveness leads to an improvement in lung function, asthma control, but does not attenuate the airway response to a cold stimulus.”
Perelman JM, Prikhodko AG. Does tobacco smoking influence the effectiveness of ICS/LABA controller therapy in asthma patients with persistent cold airway hyperresponsiveness? Presented at: the American Thoracic Society (ATS) 2022 International Conference; May 13-18, 2022; San Francisco, CA. Abstract 707.