One of the most effective treatments for chronic obstructive pulmonary disease (COPD) — pulmonary rehabilitation — could potentially work even better if programs were designed based on gender, according to a UC Davis pulmonary physician.
Today more women than men are diagnosed with COPD, which typically involves chronic bronchitis, emphysema or both. The disease also progresses more quickly for women. In fact, between 1980 and 2000, COPD death rates for women tripled. Since 2000, more women than men have died each year from the disease.
The reasons for this disparity are not clear, but Katherine Cayetano, who is completing her pulmonary medicine fellowship at UC Davis, is determined to close the gender gap.
“It is assumed that women have some unique susceptibilities for obstructive airway disease,” said Cayetano. “It’s also possible that there is a bias against giving a diagnosis of COPD to women until it is more advanced and more difficult to treat. But research that could help us better understand how the disease and its treatments differ for women is almost nonexistent.”
Cayetano is focusing first on pulmonary rehabilitation, which is associated with improved quality of life, decreased exacerbations and lower costs. At UC Davis, the program combines exercise therapy, counseling, behavior modification and education to improve the capacities to breathe and cope with progressive, chronic lung disease.
Cayetano conducted preliminary, retrospective research to find out if men and women participating in the same pulmonary rehabilitation program experienced different outcomes in terms of changes in endurance, strength and functional status. Hers was the first study to evaluate gender differences for a comprehensive pulmonary rehabilitation program like the one at UC Davis.
“We know that pulmonary rehabilitation works, especially when it involves more than just exercise, but we don’t know if its benefits differ for certain groups,” she said. “We could be missing important opportunities to make pulmonary rehab more effective.”
Cayetano reviewed the charts of 33 patients (18 women and 15 men) and their scores on a variety of physical activities and health measures before and after eight weeks of pulmonary rehabilitation. Most of the patients had COPD, although some did not. All were outpatient participants in pulmonary rehabilitation at UC Davis Medical Center between July 2009 and July 2012.
The results, which she shared May 3 during the “Art and Science of Pulmonary Rehabilitation” conference in Sacramento, showed that both men and women with COPD improved on all measures, including knowledge and management of their disease, general mood, sleep quality, stamina and strength. However, the before and after differences on a key measure of stamina — six-minute walk test distances — was only statistically significant for males.
“This was distressing to see, since levels of improvement on the six-minute walk test are linked with survival,” said Cayetano.
Cayetano also found that, while both groups improved on measures of mood, women scored much lower than men at the beginning of the program. This means that women were more likely to experience depression with COPD.
“This could be because women are usually the ones running households and taking care of everyone, and being incapacitated hits them harder,” said Cayetano.
Cayetano said pulmonary rehabilitation outcomes could potentially equalize if women with COPD received more attentive evaluation and intervention for mood-related symptoms, along with more oversight and support for skills that build stamina. She doesn’t want to reach conclusions without a broader study that includes more programs.
“My colleagues Lam Nguyen (a pulmonary medicine fellow) and Kimberly Hardin (professor of pulmonary medicine) are preparing to embark on a larger, prospective study,” said Cayetano. “If that shows true differences in how pulmonary rehabilitation affects men and women, then we should think about tailoring pulmonary rehab programs to be specific to their needs.”