Unique features of non-obstructive emphysema and pure airway obstruction.

Correspondence to: Joo Hun Park, Department of Pulmonary and Critical Care Medicine, Ajou University School of Medicine, Worldcup Road 164, San 5, Wonchon-dong, Yeongtong-gu, Suwon, Gyeonggi-do 443-721, South Korea. Tel: (+82) 31-219-5116. Fax: (+82) 31-219-5124. e-mail: jhpamc@hanmail.net Article submitted 10 April 2013. Final version accepted 21 August 2013. S E T T I N G : Emphysema without airway obstruction or airway obstruction without emphysema are often detected clinically, although they are commonly co-existent. We therefore tested the hypothesis that non-obstructive emphysema and pure airway obstruction have unique features. M E T H O D S : A case-control observation study was undertaken retrospectively in a patient cohort at a single centre. Among 2662 subjects who underwent chest computed tomography and pulmonary function tests, we enrolled 90 patients with non-obstructive emphysema, 119 with pure airway obstruction, 81 with obstructive emphysema and 2031 subjects as normal controls. The features of the four groups were analysed and compared. R E S U LT S : Higher serum homocysteine (13.4 ± 7.4 vs. 11.6 ± 4.6 μmol/l), higher rate of osteoporosis (15.8% vs. 4.5%), higher leukocyte count, higher male ratio, lower serum albumin and lower body mass index were observed in subjects with non-obstructive emphysema than in controls (P < 0.05). In multiple logistic regression analysis of groups without airway obstruction, osteoporosis, hyperhomocysteinaemia, hypoalbuminaemia and higher leukocyte count were independent factors associated with non-obstructive emphysema (P < 0.05). C O N C L U S I O N : Hyperhomocysteinaemia, hypoalbuminaemia, osteoporosis and higher leukocyte count were independent predictors of non-obstructive emphysema. K E Y W O R D S : emphysema; airway obstruction; serum homocysteine; osteoporosis