ATLANTA—It seems increasingly unlikely that the US Department of Health and Human Services (HHS) will achieve the goals it set for the reduction of chronic obstructive pulmonary disease (COPD) in its Healthy People 2010 initiative. A recent study by the CDC found that most measures of COPD prevalence, morbidity, and mortality are continuing to climb.[1]

In the study, the CDC estimated that the number of American adults who reported having COPD increased from 7.1 million to more than 10.5 million between 1980 and 2000. During that interval, the annual number of physician’s office and hospital outpatient visits made by patients for COPD rose from about 5.5 million to 8 million.

In addition, the estimated annual number of emergency department visits for COPD climbed from 1.1 million to 1.5 million, while the number of COPD-related hospitalizations went from about 652,000 to 726,000. Deaths from COPD more than doubled, rising from about 52,000 to more than 119,000.

HHS had hoped to reduce the proportion of adults ages 45 and older whose activities are limited by COPD to 1.5% in 2010 (from 2.2% in 1997). It had also wanted to lower COPD-related mortality in that group from 119.4 deaths per 100,000 persons (the 1998 figure) to 60 per 100,000.

MULTIPLE DATA SOURCES

For the study, information on COPD prevalence was derived from two sets of surveys conducted by the National Center for Health Statistics (NCHS): the National Health Interview Survey (NHIS) and the National Health and Nutrition Examination Survey (NHANES). Data on physician’s office, emergency department, and hospital outpatient visits and on hospitalizations and deaths due to COPD were available from three other NCHS surveys: the National Ambulatory Medical Care Survey, the National Hospital Ambulatory Medical Care Survey, and the National Hospital Discharge Survey. Statistics on COPD-related mortality were also extracted from the mortality component of the National Vital Statistics System.

Pulmonary function and functional limitation data were taken from the NHANES. Information on activity limitation was derived from the NHIS.

DISEASE INCREASED AMONG WOMEN

Although men had markedly higher COPD mortality rates during the 20-year study, those rates rose much more rapidly in women—from 20.1 per 100,000 in 1980 to 56.7 per 100,000 in 2000 (in those same years, mortality in men rose from 73 to 82.6 per 100,000). The result: 2000 was the first year in which more women than men died of COPD (59,936 vs 59,118).

Since the 1980s, more women than men have reported having COPD; however, the difference between the sexes has grown in magnitude over time. In 2000, 6.7 million women, compared with 3.8 million men, reported having COPD. Substantially more women are being hospitalized for the disease as well (in 2000, 404,000 women vs 322,000 men).

“COPD used to be primarily a men’s disease, but now it is clearly important in both sexes—and perhaps even more so in women,” lead study author David M. Mannino, MD, told RESPIRATORY REVIEWS. Dr. Mannino is a Medical Epidemiologist in the Division of Environmental Hazards and Health Effects at the CDC.

EVIDENCE OF UNDERDIAGNOSIS

The study authors estimated that about 24 million Americans show signs of COPD. About half of these individuals have mild obstructive lung disease, defined by a ratio of forced expiratory volume in one second to forced vital capacity (FEV1:FVC) below 70% and an FEV1 of 80% or more of predicted. The remaining patients have moderate airway obstruction, as evidenced by an FEV1:FVC below 70% and an FEV1 below 80% of predicted.

“In these people, limitations such as the inability to walk as far as they used to may inaccurately be attributed to age rather than to their decline in lung function,” Dr. Mannino remarked. Thus, COPD is probably markedly underdiagnosed, he said.

There is some good news, though. The study found a statistically significant decrease in the proportion of persons younger than 55 years who have evidence of mild or moderate COPD on pulmonary function tests. “It would seem that the smoking prevention programs that started in the mid-1960s are having an effect on the younger population,” Dr. Mannino speculated.

He suggested that pulmonary function testing be used more often to screen for undiagnosed COPD in adults. Continued surveillance, better interventions on a public health level, and cooperation between the CDC and state and local health departments, national organizations (such as the American Lung Association), and patient advocacy groups are necessary to promote knowledge and public awareness of COPD, he added.

—Timothy Begany