Chronic Obstructive Pulmonary Disease: Epidemiology, Clinical Presentation, and Evaluation

In 2010, COPD was responsible for an estimated 10.3 million physician office visits, with a resulting age-adjusted rate of 494.8 per 10,000 US civilian population [16]. COPD was also responsible for an estimated 1.5 million emergency room visits, with a resulting age-adjusted rate of 72 visits per 10,000 population [16].

COPD is a leading cause of hospitalization in US adults, particularly in older populations. In 2010, almost 699,000 hospitalizations, were attributed to COPD. The age-adjusted rate of COPD hospitalizations (as the primary cause of hospitalization) was 32.2 per 10,000 population in 2010 [16].

Deaths due to or associated with COPD have not significantly changed since 1999. While the age-adjusted death rate among men declined during 1999–2010 ( P = 0.001), the rate among women has not changed significantly ( P = 0.127). In 2010, 63, 778 men and 69, 797 women aged ≥ 25 years died of COPD [26]. One of the limitations of using the mortality component of the National Vital Statistics System is that it is based on the underlying cause of death as reported on the death certificate; however, many decedents with COPD listed on the death certificate have their death attributed to another cause [27]. The significance of COPD as a contributor to death is undefined when it is present with diseases more likely to be attributed as the underlying cause of death, such as myocardial infarction or lung cancer [28].

COPD is a very costly disease, with estimated direct medical costs in 2004 of $20.9 billion. The estimated indirect costs related to morbidity (loss of work time and productivity) and premature mortality is an additional $16.3 billion, for a total of $37.2 billion [29]. Because COPD may be present but not listed as the underlying cause of death or the primary reason for hospitalization, these cited estimates may underestimate the true cost of COPD. For example, in another analysis of COPD costs in the US, the total for 2010 was estimated at $32.1 billion [30], but could be up to $100 billion [31] depending on the assumptions surrounding comorbid disease.

Another manifestation of the importance of COPD is its effect on the burden of disease in a population determined using disability-adjusted life-years (DALYs). DALYs for a disease or condition are calculated as the sum of the years of life lost due to premature mortality in the population and the years of life lost due to disability [32]. In 2010, COPD was estimated to be the second leading cause of DALYs lost among the North American population [33]. Worldwide, COPD is expected to move up from being the twelfth leading cause of DALYs lost in 1990 to the fifth leading cause in 2020 [34].

Gender Differences

Smoking-related diseases such as COPD and lung cancer are continuing to increase among women in the United States [35,36], while they have plateaued or are decreasing among men [27,37]. Some evidence has emerged that compared with men at a similar level of tobacco smoking, women may be more likely to develop COPD [38] or that the severity of COPD in women may be increased [39–41].