Association of cardiac autonomic functions with inflammatory markers in chronic obstructive pulmonary disease.

Abstract

Chronic obstructive pulmonary disease (COPD) is an inflammatory lung disorder. Serum matrix metalloproteinase-9 (MMP-9) protein, a sensitive biomarker of COPD and other inflammatory markers such as interleukin-6 (IL-6), C-reactive protein (CRP), and fibrinogen, were found to be elevated in these patients. Autonomic dysfunction plays a key role in the pathophysiological mechanism of COPD. This study aimed to understand the association of autonomic function with inflammatory markers in COPD patients. Patients diagnosed with COPD aged 40-70 years (<i>n</i> = 52) were recruited from the pulmonary medicine department. Their heart rate variability (HRV), pulmonary function test (PFT), and inflammatory markers such as MMP-9, IL-6, CRP, and fibrinogen were measured and compared with age-matched apparently healthy controls (<i>n</i> = 50). The association between autonomic function and inflammatory markers was analyzed by correlation analysis. In the COPD patients, the PFT parameters were significantly reduced compared to controls; the HRV parameters showed reduced vagal tone and higher sympathetic tone and sympathovagal imbalance. The inflammatory markers were increased in COPD subjects. MMP-9, IL-6, and CRP were significantly and negatively correlated with total power, the markers of vagal tone and CRP was significantly and positively correlated with the marker of sympathovagal imbalance. The present study found that in the COPD subjects, there was reduced vagal tone and higher sympathetic tone with sympathovagal imbalance. The inflammatory markers were increased and were negatively correlated with vagal tone and positively correlated with sympathovagal imbalance in COPD subjects.