The Science Journal of the American Association for Respiratory Care

Special Articles

October 2002 / Volume 47 / Number 10 / Page 1184

Chronic Obstructive Pulmonary Disease Surveillance—United States, 1971–2000

David M Mannino MD, David M Homa PhD, Lara J Akinbami MD, Earl S Ford MD, and Stephen C Redd MD

Introduction
Methods
      Self-Reported Prevalence
      Objectively Determined Prevalence
      Activity and Functional Limitations
      Physician Office Visits, Hospital Outpatient Department
         Visits, and Emergency Department Visits
      Hospitalizations
      Mortality
Results
      Prevalence
      Activity and Functional Limitations
      Physician Office and Hospital Outpatient Department Visits
      Emergency Department Visits
      Hospitalizations
      Deaths
Discussion
PROBLEM/CONDITION: Chronic obstructive pulmonary disease (COPD) includes chronic bronchitis and emphysema but has been defined recently as the physiologic finding of nonreversible pulmonary function impairment. This surveillance summary reports trends in different measures of COPD during 1971-2000. REPORTING PERIOD COVERED: This report presents national data regarding objectively determined COPD (1971-1994); COPD-associated activity and functional limitations (1980-1996); self-reported COPD prevalence, COPD physician office and hospital outpatient department visits, COPD hospitalizations, and COPD deaths (1980-2000); and COPD emergency department visits (1992-2000). DESCRIPTION OF SYSTEMS: The Centers for Disease Control's National Center for Health Statistics conducts the National Health Interview Survey annually, which includes questions concerning COPD and activity limitations. The National Center for Health Statistics collects physician office-visit data in the National Ambulatory Medical Care Survey, emergency department and hospital outpatient department data in the National Hospital Ambulatory Medical Care Survey, hospitalization data in the National Hospital Discharge Survey, and death data in the Mortality Component of the National Vital Statistics System. Data regarding pulmonary function were obtained from the National Health and Nutrition Examination Surveys (NHANES) I (1971-1975) and III (1988-1994), and data regarding functional limitation were obtained from NHANES III, Phase 2 (1991-1994). RESULTS: During 2000, an estimated 10 million U.S. adults reported physician-diagnosed COPD. However, data from NHANES III estimate that approximately 24 million United States adults have evidence of impaired lung function, indicating that COPD is underdiagnosed. During 2000, COPD was responsible for 8 million physician office and hospital outpatient visits, 1.5 million emergency department visits, 726,000 hospitalizations, and 119,000 deaths. During the period analyzed, the most substantial change was the increase in the COPD death rate for women, from 20.1/100,000 in 1980 to 56.7/100,000 in 2000, compared with the more modest increase in the death rate for men, from 73.0/100,000 in 1980 to 82.6/100,000 in 2000. In 2000, for the first time, the number of women dying from COPD surpassed the number of men dying from COPD (59,936 vs 59,118). Another substantial change observed is that the proportion of the population aged < 55 years with mild or moderate COPD, on the basis of pulmonary function testing, decreased from 1971-1975 to 1988-1994, possibly indicating that the upward trends in COPD hospitalizations and mortality might not continue. INTERPRETATION: COPD is a major cause of morbidity, mortality, and disability in the U.S. Despite its ease of diagnosis, COPD remains an underdiagnosed disease, chiefly in its milder and more treatable form.
Key words: chronic obstructive pulmonary disease, COPD, bronchitis, emphysema, pulmonary, survey.
[Respir Care 2002;47(10):1184–1199]

Introduction

Chronic obstructive pulmonary disease (COPD) is a group of diseases characterized by air flow obstruction that can be associated with breathing-related symptoms (eg, chronic cough, exertional dyspnea, expectoration, and wheeze). COPD can be present with or without substantial physical impairment or symptoms, and it is the fourth leading cause of death in the United States. However, COPD is often a silent and unrecognized disease, chiefly in its early phases. During 1993, the estimated direct medical costs of COPD were $14.7 billion. Also during 1993, the estimated indirect cost related to morbidity (eg, loss of work time and productivity) and premature mortality was an additional $9.2 billion, for a total of $23.9 billion. Healthy People 2010 includes 2 objectives related to COPD: to reduce the proportion of adults whose activity is limited because of chronic lung and breathing problems to 1.5% (Objective 24-9) and to reduce deaths from COPD among adults aged > or = 45 years to 60 deaths/100,000 (Object 24-10).

See the Related Editorial on Page 1148

Traditionally, COPD has been diagnosed on the basis of patient-reported symptoms. The recently published definition from the Global Initiative for Chronic Obstructive Lung Disease (GOLD) has classified COPD as "a disease state characterized by air flow limitation that is not fully reversible" and recommends measurement of lung function both to diagnose disease and categorize disease severity. Air flow limitation is the slowing of expiratory air flow as measured by spirometry, with a persistently low forced expiratory volume in the first second (FEV1) and a low FEV1/forced vital capacity (FVC) ratio despite treatment. The GOLD criteria for mild COPD (stage 1) is an FEV1/FVC ratio of < 70% and FEV1 of > 80% predicted, and the criteria for moderate COPD (stage 2 or 3) is an FEV1/FVC ratio of < 70% and an FEV1 < or = 80% predicted.

This report presents national data regarding objectively determined (ie, by spirometry) COPD (1971-1994); COPD-associated activity and functional limitations (1980-1996); self-reported COPD prevalence, COPD physician office and hospital outpatient department visits, COPD hospitalizations, and COPD deaths (1980-2000); and COPD emergency department visits (1992-2000).

The entire text of this article is available in the printed version of the October 2002 RESPIRATORY CARE.

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