Clinical, demographic and radiological profile of smoker COPD versus nonsmoker COPD patients at a tertiary care center in North India

Abstract

Introduction: Cigarette smoking is the most predominant risk factor for development of chronic obstructive pulmonary disease (COPD). However, a considerable amount of patients do develop COPD without exposure to cigarette smoking. We aimed to analyze the incidence, demographic and clinical profile of nonsmoker COPD subjects at a tertiary care center.

Methods: In this prospective observational study, 410 patients were screened for dyspnea. On the basis of spirometry findings, 360 patients were diagnosed as COPD and enrolled into the study. Patients were categorized into 2 groups on the basis of smoking habits (smoker and nonsmoker COPD). Clinical and demographic attributes were compared in between these two groups. This study was conducted over a period of one year, from August 2014 to July 2015. All statistical analyses were performed using Statistical Package for the Social Sciences version 19.0 (SPSS Inc, Chicago, IL, USA). Values were considered to be statistically significant at P < 0.05.

Results: Out of 360 COPD cases, about 2/3^rd (60%) were smokers and the rest nonsmokers. Majority of the patients were in the age group of 51-70 years. The mean age of smokers with COPD was significantly higher than nonsmokers with COPD (59.29 ± 10.28 years vs. 53.90 ± 8.77 years; P = 0.0001). Overall, males were predominant (57.2%) but there were higher number of female patients in nonsmoker group (25% vs. 70%; P = 0.001). At presentation, majority of nonsmoker with COPD were in GOLD severity grade II while in the smoking cohort majority were in GOLD severity Grade III. Among the 144 nonsmoker COPD patients, the most important and statistically significant risk factor was exposure to biomass smoke (68.06%). Other risk factors were long-standing asthma (37.50%), lower respiratory tract infection in childhood (32.60%), exposure to outdoor air pollution (17.92%).

Conclusion: Nonsmoker COPD is emerging as a distinctive phenotype. They have less impairment in airflow limitation, and a lower prevalence of emphysema, chronic cough, and sputum compared with their smoking counterparts.

Keywords: Biomass fuel exposure; chronic obstructive pulmonary disease; nonsmoker; smoker; spirometry.

Figure 1

Distribution of age among smoker versus nonsmoker with COPD

Figure 2

Gender distribution of the smoker and nonsmoker. The Chi-square statistic is 62.1032. The P value is < 0.00001

Figure 3

Distribution of GOLD class among the smoker and nonsmoker patients with COPD