Man Versus Woman: How COPD Affects the Sexes Differently

Key Point

Severe COPD-related emphysema is less extensive in women than in men. However, greater prevalence of additional symptoms results in a greater burden of COPD in women.

Analysis of data from a subset of patients from the National Emphysema Treatment Trial has illuminated distinct patterns of severe emphysema in men with COPD that are different from those in women. As reported in the August 1 American Journal of Respiratory and Critical Care Medicine, emphysema appeared to be less severe in women than in men; however, other disease manifestations, including dyspnea, depression, and low quality of life, were more severe in women than in men, indicating an “increasingly disproportionate burden” of COPD on women.

“By simultaneously correlating symptoms with carefully standardized physiological, radiological, and histological data, these results for the first time unite several previously separate lines of investigation in women’s health and COPD,” asserted Fernando J. Martinez, MD, Professor of Internal Medicine and Director of Pulmonary Diagnostic Services at the University of Michigan in Ann Arbor, and colleagues.

All 1,053 study participants—409 of whom (38.8%) were women—had been previously diagnosed with severe COPD and were evaluated for lung volume reduction surgery. Chest CT indicated that the proportion of whole-lung emphysema was lower in the women than in the men, with an average of 3% less moderate emphysema (defined as -910 Hounsfield units [HU]) and 16.4% less severe emphysema (defined as -950 HU). The researchers also noted that women had a lower proportion of severe emphysema in the peel of the lung, indicating less peripheral involvement, while proportions of emphysema in the core of the lung were similar between the sexes. Histological assessment of lung tissue samples in a subgroup of 59 men and 42 women who underwent the volume reduction surgery showed that the walls of small airways were thicker in the women.

“Taken together, these findings imply that in women, tobacco damages the lungs more centrally in the airways and less in the very distal gas-exchanging regions,” study coauthor Jeffrey L. Curtis, MD, told Pulmonary Reviews. Dr. Curtis is Chief of the Pulmonary and Critical Care Medicine Section at the Veterans Affairs Medical Center in Ann Arbor and is also Professor of Internal Medicine at the University of Michigan.

Dr. Curtis continued, “In terms of manifestations and symptoms, it could be argued that women with advanced COPD suffer more greatly than do men.” Generally, the women included in the study were younger than the men, had fewer pack-years of smoking, and had a greater prebronchodilator FEV1 percent predicted. However, even after adjustment for those confounders and proportion of whole-lung emphysema, women had greater dyspnea, as measured by the University of California, San Diego Shortness of Breath Questionnaire. Depression was detected by the Beck Depression Inventory.

“Our data suggest that women under the age of 79.2 years tended to have a higher total Beck score than men, but as age increased, the total Beck score tended to decrease more rapidly in women than in men,” stated the authors. The mental component scores of the Short Form 36 Health Survey, which appraised quality of life, followed a similar pattern, with women under the age of 73.5 having worse scores than men of the same age and the disparity lessening with increasing age.

The take-home message, concluded Dr. Curtis, is that clinicians should increase their suspicion of COPD as a cause of shortness of breath in women. “All too often, women with modest smoking histories are diagnosed as having asthma rather than COPD due to the greater levels of anxiety, or are labeled as having purely functional complaints,” he said. “More widespread use of pulmonary function testing—
especially, but not only, in women—could lead to correct diagnoses sooner.”

In an accompanying editorial, Dawn L. DeMeo, MD, MPH, of the Center for Chest Diseases at the Brigham and Women’s Hospital in Boston, cited a 2002 National Center for Environmental Health report that stated that the number of women who died of COPD in 2000 surpassed the number of men.

“Studying the yin and yang of COPD will lead to insights about COPD pathophysiology as a whole,” she asserted. “What is not debatable is that there are sex and gender differences in COPD to consider in both research and clinical care of patients.”           

—Jessica Dziedzic

Reference
DeMeo DL. The yin and yang of COPD: Sex/gender differences in the National Emphysema Treatment Trial. Am J Respir Crit Care Med. 2007;176(3):222-223.
Mannino DM, Homa DM, Akinbami LJ, et al. Chronic obstructive pulmonary disease surveillance—United States, 1971-2000. MMWR Surveill Summ. 2002;51(6):1-16.
Martinez FJ, Curtis JL, Sciurba F, et al. Sex differences in severe pulmonary emphysema. Am J Respir Crit Care Med. 2007;176(3):243-252.

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