Number of asthma triggers predicts uncontrolled disease
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LOUISVILLE, Ky. — The number of patient-reported triggers strongly predicted uncontrolled asthma disease burden, according to a presentation at the American College of Allergy, Asthma & Immunology Annual Scientific Meeting.
“Patients who experience more triggers have poorer clinical outcomes, including lower overall asthma-related quality-of-life scores,” Bradley E. Chipps, MD, medical director of respiratory therapy and the cystic fibrosis center at Sutter Medical Center in Sacramento, California, said during his presentation.
The researchers examined data from 1,434 patients with confirmed severe asthma treated by subspecialists in the United States who enrolled in the ongoing CHRONICLE observational study between February 2018 and February 2021.
These patients completed a questionnaire asking them about 16 prespecified categories of asthma triggers, in addition to the Asthma Control Test (ACT), for which higher scores indicate better disease control; the St. George’s Respiratory Questionnaire (SGRQ), with higher scores indicating poorer quality of life; and the Work Productivity and Activity Impairment Asthma questionnaire, with higher scores indicating worse impairment.
All the patients reported at least one trigger, with a median number of triggers per patient of eight (interquartile range, 5-10). Changes in the air or weather (77%), viral infections (70%), year-round allergies (67%) and seasonal allergies (66%) were the most common triggers.
“Women, younger patients, Black patients and patients receiving maintenance systemic corticosteroids were more likely to report a higher number of triggers,” Chipps said.
Compared with patients who reported between one and three triggers, patients who reported more triggers experienced more poorly controlled disease, worse quality of life, reduced work productivity and more exacerbations, Chipps continued.
For example, patients with one to three triggers had a mean ACT score of 19 (standard deviation [SD], 4). Scores decreased through subgroups with four to six, seven to nine, and 10 to 13 triggers before bottoming out among those with 14 to 17 triggers and a mean ACT score of 11 (SD, 5).
Those with one to three triggers had a mean SGRQ score of 28 (SD, 19), with increasing scores among the subgroups based on numbers of triggers before peaking among those with 14 to 17 at 62 (SD, 21).
Impairment scores increased as well from means of 11 (SD, 18) for work and 18 (SD, 23) for activity for those with one to three triggers to 41 (SD, 28) for work and 57 (SD, 32) for activity for those with 14 to 17 triggers.
Based on the 1,296 patients with complete data, final multivariate models found that age, BMI and the number of triggers were the only significant predictors of asthma exacerbation among the variables that the univariate analysis found significant.
Also, the base annual exacerbation rate of 0.4 per patient-year increased by 7% for each additional trigger (RR = 1.07; 95% CI, 1.03-1.11)
Researchers further identified BMI and the number of triggers further as the only significant predictors of hospitalization rates among the variables considered significant on univariate analysis.
The base annual asthma hospitalization rate of 0.06 per patient-year increased by 17% for each additional trigger (RR = 1.17; 95% CI, 1.08-1.27).
The area under the curve receiver operating characteristic for trigger number was higher than blood eosinophil count in predicting one or more exacerbations (0.6 vs. 0.53) and one or more asthma hospitalizations (0.67 vs. 0.51).
“The number of triggers was a better predictor than blood eosinophil count of disease morbidity across multiple measures,” Chipps said. “This highlights the importance of understanding patient-reported triggers in severe asthma treatment.”