In patients with asthma, chronic cough is linked with greater systemic inflammatory biomarker blood levels, higher utilization of health care, poorer respiratory symptoms, and a more acute disease phenotype, according to a study published in The Journal of Allergy and Clinical Immunology: In Practice.
This cross-sectional study included data from 14,740 adults with asthma and chronic cough from the Copenhagen General Population Study. Asthma was self-reported, as were data on chronic cough and asthma medication use. Data on healthcare utilization, blood biomarker levels, lung function, and respiratory symptoms were also collected. Clinical outcomes included wheeze, prior bronchitis and/or pneumonia in the past 10 years, doctor’s visits in the past 12 months, spirometry measures, and blood biomarker levels. Continuous data were evaluated using Wilcoxon’s rank sum test, and categorical data were evaluated with Fischer’s exact or Pearson’s chi-squared test. Logistic regression was used to assess hospitalization risk due to pneumonia and asthma.
In the study population, 6% (n=855) had asthma, with 8% (n=70) of these participants experiencing chronic cough and having a median total score of 16.8 (14.8-18.9; 25th and 75th percentiles) on the Leicester Cough Questionnaire (physical, 5.4 [4.6-6.0]; social, 6.0 [5.3-6.8]; psychological, 5.7 [4.6-6.4]). Compared with asthma alone, chronic cough and asthma correlated with higher reports of wheeze (70% vs 54%; P <.05), nighttime dyspnea (27% vs 11%; P <.005), chest pain or tightness (14% vs 4%;P <.005), visits to a general practitioner (60% vs 45%; P <.05), episodes of acute pneumonia or bronchitis (21% vs 10%; P <.05), dyspnea (74% vs 49%; P <.005), production of sputum (59% vs 14%; P <.005), forced expiratory volume in 1 second predictions of <60% (14% vs 7%), and blood levels of fibrinogen, leukocytes, and neutrophils.
Limitations to this study included the self-reported nature of the population’s asthma diagnoses, a small sample size, a lack of information on the duration of cough, a cross-sectional study design, and low granularity of asthma due to the definition of treatment.
The study researchers concluded that “among individuals with asthma, those with chronic cough vs those without had worse respiratory symptoms, greater healthcare utilizations, lower lung function, and higher levels of systemic inflammatory biomarkers in blood. The results show that chronic cough in individuals with asthma is associated with a more severe disease phenotype.”
Disclosures: Certain authors report financial associations with pharmaceutical companies. For a full list of author disclosures, please see the reference.
Çolak Y, Afzal S, Lange P, Laursen LC, Nordestgaard BG, Dahl M. Role and impact of chronic cough in individuals with asthma from the general population [published online March 2, 2019]. J Allergy Clin Immunol Pract. doi:10.1016/j.jaip.2019.02.021