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Review

Chronic obstructive pulmonary disease in African- and European-American women: morbidity, mortality and healthcare utilization in the USA Expert Rev. Respir. Med. 9(2), 161–170 (2015)

Alem Mehari and Richard F Gillum* Department of Medicine, Howard University College of Medicine, Washington, DC, 20060, USA *Author for correspondence: [email protected]

The impact of chronic obstructive pulmonary disease (COPD) is increasing in US women. In 2008–2010, an estimated 7.9 million US women were living with COPD. Chronic lower respiratory disease was the third leading cause of mortality in 2010 and was a major cause of morbidity. Its economic and social burden is both substantial and increasing in the USA. The annual number of COPD deaths is now higher in women than in men. In 2011, 72,584 women and 65,920 men aged 25 years and over died of COPD. The death rate in African-American women was only half compared with European-American women. Further, rates of COPD prevalence, emergency room visits and hospitalization were greater among women than men. This review reports the latest patterns and trends in several measures of COPD in US women. KEYWORDS: chronic bronchitis . chronic obstructive . disease frequency . healthcare . pulmonary disease . pulmonary emphysema . surveys

Chronic obstructive pulmonary disease (COPD), a common preventable and treatable disease, is characterized by persistent airflow limitation that is usually progressive and associated with an enhanced chronic inflammatory response to noxious particles or gases in the airways of the lung [1]. COPD includes both chronic bronchitis and emphysema, conditions which often coexist. COPD is a leading cause of morbidity and mortality worldwide and results in an economic and social burden that is both substantial and increasing. The Global Burden of Disease Study projected that COPD, which ranked sixth as a cause of death in 1990, will become the third leading cause of death worldwide by 2020 [2]. In the USA, COPD affects more than 5% of the adult population; it was the 3rd leading cause of death and the 12th leading cause of morbidity in 2010. The total economic costs of COPD

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10.1586/17476348.2015.1016502

were estimated to be US$49.9 billion in 2010, and the total direct cost of medical care is approximately US$29.5 billion per year [3]. In contrast to other major chronic diseases in the USA, COPD has not shown major declines in mortality over the past 30 years. From a global perspective, population-based studies on prevalence for COPD published between 1990 and 2004 reported a pooled prevalence for COPD at 9.8% among men and 5.6% among women [4]. A study in five Latin American cities using probability sampling and confirmation with spirometric testing also reported that the age-adjusted prevalence was higher for men than women in every city sampled, ranging from 11.4% of men to 7.5% of women in Mexico City, to 23% of men and 11.6% of women in Montevideo [5]. However, the most recent survey from an economically advanced country,

 2015 Informa UK Ltd

ISSN 1747-6348

161

Review

Mehari & Gillum

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due to COPD and discuss possible explanations for the increasing burden of disease in the US women. This information will be of value to clinicians, R&D scientists, regulatory and marketing professionals in the pharmaceutical industry and decision-makers in public health and the healthcare industry.

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5 4 3

Prevalence of physician-diagnosed COPD

Female All Male

2 1 0 1999–2001

2002–2004 2005–2007 3 year period

2008–2010

Figure 1. Prevalence† of chronic obstructive pulmonary disease among adults aged 18 and over: USA, 1999–2010. † Age adjusted to the 2000 US standard population.

Austria, using carefully standardized methods identical to the methods used in the Latin American surveys, found an equal prevalence of COPD in men and women, and equal tobacco use [6] indicating the majority of female smokers are in developed countries. Smoking exposure is the most important risk factor for the development of COPD, accounting for up to 80% of all cases. Other risk factors include exposure to noxious particles or gases, recurrent infection, diet and genetic factors [7]. Mortality trends reflect patterns of initiation of cigarette smoking that occurred 30–50 years previously [8]. Current mortality trends indicate that COPD mortality may be leveling off among white males, but will continue to increase among women, AfricanAmericans and the elderly [9]. Prevalence and healthcare utilization for COPD are also increasing in women in the USA [9]. We present recent (1999–2011) national trends in the prevalence, emergency room visits, hospitalizations and mortality

13 11

Female Male

9 Percent

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Percent

6

7 5 3 1 25–44

45–54

55–64

65–74

75–84

≥85

Age group (years)

Figure 2. Prevalence of chronic obstructive pulmonary disease among adults aged 18 and over, by age group and sex: USA, annual average 2008–2010.

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The data are from the National Health Interview Survey (NHIS), a continuous national survey of the civilian noninstitutionalized population of the USA. Data are collected through in-person computer-assisted household interviews. Estimates on COPD are available only for adults aged 18 years and older [10–14]. The prevalence of COPD is estimated as the percent of persons who answered ‘yes’ to at least one of the following two questions: ‘During the past 12 months, have you been told by a doctor or other health professional that you had chronic bronchitis?’ OR ‘Have you ever been told by a doctor or other health professional that you had emphysema?’ NHIS data are based entirely on self-report. Since validation of diagnosis was not available, diagnostic accuracy in NHIS is uncertain. Distinguishing COPD from adult asthma may pose a problem [14–17]. From a sociologic standpoint, women consistently are more likely to report symptoms, give poorer selfevaluation of health, have more chronic conditions and visit physicians more often, which may bias the NHIS data toward increased reported prevalence of disease in women [18,19]. Prevalence estimates of COPD by age, sex and race/ethnicity are presented. Estimates are presented as 3-year annual averages to obtain stable estimates. In 2008–2010, 5.4% (12.6 million) of the US adults aged 18 years and over were estimated to have COPD, a rate that was stable from 1999 through 2010. The total number of COPD conditions in adults is calculated as the estimated number of chronic bronchitis and emphysema cases together while taking into account the overlap of persons who have both diseases. For each 3-year period from 1999 through 2010, women had higher COPD prevalence than men (FIGURE 1). For 2008–2010, 6.4% of women (7.9 million) reported COPD compared with 4.3% of men (4.7 million). The prevalence of COPD rose with age for both men and women throughout most of the lifespan (i.e., across most age groups). COPD prevalence was highest among women aged 65–74 (10.9%) and 75–84 (10.9%) and among men aged 75–84 (10.9%) (FIGURE 2). COPD prevalence was greater among women than men in all age groups except the two highest age groups (75–84 and 85 and over), for which the difference was not statistically significant. In 2008, 23.2% of adults with COPD aged 45 years and older experienced activity limitations due to chronic lung and breathing problems (age adjusted to the year 2000 standard population). Overall, non-Hispanic white (6%) adults had higher COPD prevalence than non-Hispanic black adults (4.7%) Expert Rev. Respir. Med. 9(2), (2015)

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COPD in African- & European-American women

130 110 Rate per 10000

and Hispanic adults (3.5%). COPD prevalence decreased with increasing income levels: adults with family income below the federal poverty level had the highest COPD prevalence (8.4%), those at 100–199% of the poverty level had intermediate prevalence (6.8%) and those with income more than 200% of the poverty level had the lowest prevalence (4.6%).

Review

Black female 90

Black male White female

70

White male 50 30

Prevalence of COPD based on spirometry

1998–2000

2001–2003 2004–2006 Year

2007–2009

The National Health and Nutrition Figure 3. Rate of visits to emergency departments for chronic obstructive Examination Survey (NHANES) is an pulmonary disease among adults aged 18 and over, by sex and race: USA, ongoing survey of the non2008–2010. institutionalized population of the USA. During 2007–2010, NHANES obtained pre-bronchodilator pulmonary lung function data on a nation- information on hospital admissions clearly has the advantage ally representative sample aged 6–79 years and post- that a large amount of data is available, which would otherbronchodilator pulmonary lung function data for the subset of wise be very hard to collect. In comparison with mortality adults with airflow limitation [20]. Crude prevalence rates for data, hospitalization has the advantage that it is more sensitive adults aged 40–79 were higher in men than women regardless and there is less delay from onset of disease. But it is not of measurement or criteria used. For example, estimates without errors regarding validity of the diagnoses. However, (%, SE) based on pre- and post-bronchodilator spirometry data for serious morbidity administrative databases tend to be com(forced expiratory volume in 1 s [FEV1]/forced vital capacity plete and reliable. The first-listed diagnosis is taken as the principal diagnosis [FVC]

Chronic obstructive pulmonary disease in African- and European-American women: morbidity, mortality and healthcare utilization in the USA.

The impact of chronic obstructive pulmonary disease (COPD) is increasing in US women. In 2008-2010, an estimated 7.9 million US women were living with...
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