Alteration of autonomic function is associated with disease severity in patients with bronchial asthma

Abstract

Background and Aim: Abnormality in the autonomic regulation of the airway results in airway obstruction in bronchial asthma. However, autonomic abnormality in asthmatic patients is generalized and is not confined to airway only. Therefore, the present study was conducted to assess the abnormality of autonomic nervous system (ANS) and its association with disease severity in bronchial asthma patients. Methods: Sixty patients of bronchial asthma aged between 15 and 50 years were included in the study. After taking informed consent, the duration of asthma was noted in each of these patients and six noninvasive ANS testing namely deep breathing test, orthostatic test, 30:15 ratio, sustained hand grip test, valsalva manoeuvre and cold pressure test was performed. Results: The study population consisted of 60 bronchial asthma patients (34 males and 26 females) and 60 controls (32 males and 28 females). It was found that out of 60 patients, 46 patients had abnormal autonomic function test values (P < 0.001). Patients who depicted more than one abnormal autonomic function test, had bronchial asthma for more than 5 years. Similarly, 32 patients having severe asthma and 28 patients having moderate asthma showed evidence of autonomic dysfunction (P < 0.001). About 48% patients had only parasympathetic dysfunction. Conclusion: Bronchial asthma patients displayed definitive dysfunction of ANS as compared with age and sex‑matched controls. With severity and chronicity of asthma, the autonomic function was proportionately attenuated. Parasympathetic overactivity appears to be closely linked to the severity of bronchial asthma.