Phenotypic comparison between smoking and non-smoking chronic obstructive pulmonary disease

• Published in: Respiratory research Vol. 21; no. 1; pp. 50 - 12
• Main Authors: Salvi, Sundeep S., Brashier, Bill B., Londhe, Jyoti, Pyasi, Kanchan, Vincent, Vandana, Kajale, Shilpa S., Tambe, Sajid, Mandani, Kuldeep, Nair, Arjun, Mak, Sze Mun, Madas, Sapna, Juvekar, Sanjay, Donnelly, Louise E., Barnes, Peter J.
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 12.02.2020; BioMed Central; BMC
• Subjects: Age Factors; Aged; Allergic diseases; Asthma; Biomarkers; Biomass; biomass smoke; Blood; Body mass index; Body size; Bronchodilators; Case-Control Studies; Cell size; Chronic obstructive lung disease; Chronic obstructive pulmonary disease; Comparative analysis; Computed tomography; Corticoids; Corticosteroids; Cross-Sectional Studies; Demographic aspects; Diffusion rate; Emphysema; Eosinophils; Female; Females; Genetic aspects; Health aspects; Hemoglobin; household air pollution; Humans; Immunomodulators; Insulin; Leukocytes (eosinophilic); Leukocytes (neutrophilic); Lung diseases; Lungs; Male; Middle Aged; Non-Smokers; non-smoking COPD; Obstructive lung disease; Phenotype; Phenotypes; Physiology; Plethysmography; Population; Pulmonary Disease, Chronic Obstructive - diagnostic imaging; Pulmonary Disease, Chronic Obstructive - epidemiology; Pulmonary Disease, Chronic Obstructive - physiopathology; Quality of life; Respiration; Respiratory diseases; Respiratory function; Respiratory tract diseases; Rural population; Sex Factors; Signs and symptoms; small airway disease; Smokers; Smoking; Spirometry - methods; Sputum; Statistics; Tobacco Smoking - epidemiology; Tobacco Smoking - physiopathology; India; Chronic obstructive pulmonary disease; biomass smoke; small airway disease; household air pollution; non-smoking COPD
• ISSN: 1465-993X; 1465-9921; 1465-993X
• DOI: 10.1186/s12931-020-1310-9

Although COPD among non-smokers (NS-COPD) is common, little is known about this phenotype. We compared NS-COPD subjects with smoking COPD (S-COPD) patients in a rural Indian population using a variety of clinical, physiological, radiological, sputum cellular and blood biomarkers. Two hundred ninety subjects (118 healthy, 79 S-COPD, 93 NS-COPD) performed pre- and post-bronchodilator spirometry and were followed for 2 years to study the annual rate of decline in lung function. Body plethysmography, impulse oscillometry, inspiratory-expiratory HRCT, induced sputum cellular profile and blood biomarkers were compared between 49 healthy, 45 S-COPD and 55 NS-COPD subjects using standardized methods. Spirometric response to oral corticosteroids was measured in 30 female NS-COPD patients. Compared to all male S-COPD subjects, 47% of NS-COPD subjects were female, were younger by 3.2 years, had greater body mass index, a slower rate of decline in lung function (80 vs 130 mL/year), more small airways obstruction measured by impulse oscillometry (p < 0.001), significantly less emphysema (29% vs 11%) on CT scans, lower values in lung diffusion parameters, significantly less neutrophils in induced sputum (p < 0.05) and tended to have more sputum eosinophils. Hemoglobin and red cell volume were higher and serum insulin lower in S-COPD compared to NS-COPD. Spirometric indices, symptoms and quality of life were similar between S-COPD and NS-COPD. There was no improvement in spirometry in NS-COPD patients after 2 weeks of an oral corticosteroid. Compared to S-COPD, NS-COPD is seen in younger subjects with equal male-female predominance, is predominantly a small-airway disease phenotype with less emphysema, preserved lung diffusion and a slower rate of decline in lung function.