Cough-Variant Asthma Linked to Bronchial Sensitivity in Nonsmokers

Bronchial hyperresponsiveness may indicate the presence of cough-variant asthma in nonsmokers who have chronic cough, new research shows.

When diagnosing chronic cough (CC) in nonsmokers, medical professionals should know the presence of sensitive bronchial tubes in such patients often means they have cough-variant asthma (CVA), a new study in Respiratory Research details.

This research shows that sensitivity in the bronchial tubes—a condition known as bronchial hyperresponsiveness—can be considered a reliable predictor of CVA in nonsmoking adults who have CC.

Most of the patients who received their diagnosis through the first-of-its-kind study showed "significant and rapid improvement" after 4 weeks of asthma treatment, according to the research, which could help simplify the “complex” process of asthma diagnosis.

“To the best of our knowledge, there have been no previous studies on the response to anti-asthmatic therapy in CC adults with bronchial hyperresponsiveness,” the researchers wrote. “Our study suggests that CVA should be considered as a major cause of cough in patients with CC presenting with bronchial hyperresponsiveness.”

The study subjected 49 patients with both bronchial hyperresponsiveness and CC to anti-asthmatic therapy, most of whom responded positively to the treatment. The positive predictive value of bronchial hyperresponsiveness in diagnosing CVA was 87.8%, according to researchers.

They said that before administering a diagnosis of CVA, medical professionals should see how patients respond to asthma treatment. In the study, patients received their diagnosis after responding positively to the use of an inhaler, steroids, or another asthma treatment.

Their observation was performed at the Medical University of Warsaw’s Department of Internal Medicine, Pulmonary Diseases and Allergy, between 2016 and 2020. Patients received several tests, including pulmonary function testing, before beginning treatment. The cohort that ultimately received treatment was winnowed down from 250 adults with CC managed in the university’s cough center.

The study’s status as a “single-center, observational analysis with a limited number of patients” limited its effectiveness somewhat, the researchers acknowledged. Other limitations included the unavailability of a cough monitoring system at the university, which led researchers to use “patient-reported outcomes rather than objective cough measures.”

The study builds on research into bronchial hyperresponsiveness’ value as a predictor of asthma.

Although the researchers said the condition’s use in diagnosing CVA hadn’t been previously studied, they were aware of research into the condition’s use in diagnosing general asthma.

“The results of our study support the opinion that asthmatic cough diagnosis and further decision making on continuation or discontinuation of anti-asthmatic treatment should be based on thorough and objective assessment of response to therapy in patients with suspicion of CVA,” the researchers wrote.

Reference

Rybka-Fraczek A, Dabrowska M, Grabczak EM, et al. Does bronchial hyperresponsiveness predict a diagnosis of cough variant asthma in adults with chronic cough: a cohort study. Respir Res. Published online September 23, 2021. doi:10.1186/s12931-021-01845-2