The Impact of Different Smoking Behavior on Pulmonary Function and Pulmonary Hypertension Among Chinese Male Patients with Chronic Obstructive Pulmonary Disease.

ABSTRACT

Purpose: Cigarette smoking is the most recognized risk factor of chronic obstructive pulmonary disease (COPD) in China. However, there are no studies analyzing the impact of different smoking behaviors on pulmonary function and pulmonary hypertension (PH) among Chinese male patients with COPD. Patients and Methods: Chinese male smokers with COPD performed pulmonary function tests. Clinical characteristics, smoking behavior features, spirometry and echocardiographic results were compared between the two groups stratified by initial smoking age (18 years old) or complicated PH. Results: The early-smoking group had more respiratory symptoms, more severe smoking behavior, worse pulmonary function with lower FEV1%pre (38.5% vs 70.2%) and FEV1/FVC% (47.5% vs 63.8%), and higher systolic pulmonary artery pressure (sPAP 38.6 vs 33.9 mmHg) than the late-smoking group. Initiating smoking before adulthood was an independently contributing factor of ventilatory dysfunction and Global Initiative for Obstructive Lung Disease (GOLD) stage escalation. It also had a significant interaction with long smoking duration (≥30 years), characterized by markedly decreased lung volumes (VC%pre 64.0% vs 84.5%), impaired diffusing capacity (DLCO%pre 58.0% vs 76.8%) and severe emphysema (RV/TLC%pre 145.2% vs 130.2%). COPD patients complicated with PH exhibited worse ventilatory function (FEV1%pre 43.2% vs 56.2%), impaired diffusion capacity (DLCO%pre 56.7% vs 77.1%) and decreased lung volume (VC%pre 67.67% vs 75.38%). Both severe smoking behaviors and impaired pulmonary function had close correlations with sPAP. Conclusion: The early-smoking group exhibited predominantly ventilation dysfunction and had complex interactions with long smoking duration to further affect lung volume and diffusion capacity. Different smoking behaviors influenced variations of pulmonary dysfunction and comorbid PH in patients with COPD.