Sex Differences in Severe Pulmonary Emphysema

Rationale: Limited data on sex differences in advanced COPD are available. Objectives: To compare male and female emphysema patients with severe disease. Methods: One thousand fifty-three patients (38.8% female) evalu- ated for lung volume reduction surgery as part of the National Emphysema Treatment Trial were analyzed. Measurements and Main Results: Detailed clinical, physiological, and radiological assessment, including quantitation of emphysema se- verity and distribution from helical chest computed tomography, was completed. In a subgroup (n 101), airway size and thickness was determined by histological analyses of resected tissue. Women were youngerandexhibited a lowerbody massindex(BMI),shorter smoking history, less severe airflow obstruction, lower DLCO and arterial PO2, higher arterial PCO2, shorter six-minute walk distance, and lower maximal wattage during oxygen-supplemented cycle ergometry. For a given FEV1% predicted, age, number of pack- years, and proportion of emphysema, women experienced greater dyspnea, higher modified BODE, more depression, lower SF-36 mental component score, and lower quality of well-being. Overall emphysema was less severe in women, with the difference from men most evident in the outer peel of the lung. Females had thicker small airway walls relative to luminal perimeters. Conclusions: In patients with severe COPD, women, relative to men, exhibit anatomically smaller airway lumens with disproportionately thicker airway walls, and emphysema that is less extensive and characterized by smaller hole size and less peripheral involvement. What This Study Adds to the Field In patients with severe COPD, women, relative to men, exhibit anatomically smaller airway lumens with dispropor- tionately thicker airway walls, and emphysema that is less extensive and characterized by smaller hole size and less peripheral involvement.