Case Definitions for Chronic Obstructive Pulmonary Disease

Figures & data

Figure 1. Predicted lower 95% confidence limits (LLN) for FEV₁/FVC (%), for males (A) and females (B), by race/ethnicity, based on NHANES III data⁶

Figure 2. U.S. age-specific prevalences of airflow obstruction based on the following definitions: LLN-1, LLN-2, Mild COPD and Moderate COPD, as estimated from NHANES III data

Table 1. The percent prevalence (P) of airflow obstruction and the number of individuals (N, millions) estimated to have airflow obstruction, by the LLN and COPD definitions, for two age strata in the U.S. population

	Estimated U.S. population size (millions)	Mild airflow obstruction				Moderate airflow obstruction
Age group (years)		LLN-1		Mild COPD		LLN-2		Moderate COPD
		P	N × 10^6	P	N × 10^6 (%)	P	N × 10^6	P	N × 10^6 (%)
20–49	101	8.9	9.0	6.3	6.4 (−29%)	3.6	3.6	2.5	2.5 (−31%)
50–80	48	19.2	9.3	30.5	14.7 (58%)	11.8	5.7	16.1	7.8 (37%)
Total	149	12.3	18.3	14.2	21.1	6.2	9.3	6.9	10.3

^†P = U.S. population prevalence (%) of airflow obstruction based on each definition.

^‡The percentage by which the number of Mild or Moderate COPD cases differ from the number identified by the LLN-1 and LLN-2 definitions, respectively.

Figure 3. U.S. age-specific prevalences of airflow obstruction based on the following definitions: LLN-1, LLN-2, Mild COPD and Moderate COPD, as estimated from never-smokers without respiratory disease or conditions from NHANES III data (The curves were plotted using a smoothing method.)

Figure 4. U.S. age-specific prevalence of: airflow obstruction based on LLN-2, physician-diagnosed asthma, emphysema, chronic bronchitis, and self-reported symptoms of chronic bronchitis (CB), as estimated from NHANES III data

Figure 5. Percent with airflow obstruction (LLN-2) among individuals with physician-diagnosed emphysema, chronic bronchitis and asthma; among those who do not report physician-diagnosed disease (no disease); and among those who reported symptoms of chronic bronchitis (CB), as estimated from NHANES III data

Table 2. Percent prevalence of disease (P_{D +}) [or no disease (P_D-)], percent prevalence of airflow obstruction (P_AO), and the number of individuals with airflow obstruction (N_AO) (in millions), according to the mutually exclusive physician-diagnosed disease categories, estimated for the U.S. population

					Physician-diagnosed airways disease
Age group (years)	U.S. population size (millions)	No disease			Emphysema			Chronic bronchitis			Asthma
		PD -	PAO	NAO	PD +	PAO	NAO	PD +	PAO	NAO	PD +	PAO	NAO
20–49	101	88.3%	2.6%	2.3	0.5%	10.4%	0.05	5.0%	9.2%	0.5	6.2%	12.4%	0.8
50–80	48	84.2%	7.8%	3.2	4.6%	56.2%	1.3	7.2%	25.9%	0.9	4.1%	18.9%	0.4
Total	149	87.0%	4.2%	5.5	1.8%	48.0%	1.3	5.7%	16.0%	1.4	5.5%	14.0%	1.2

*P_D+/− = Percent of U.S. population with a physician-diagnosed airways disease (P_D+) or without it (P_D-).

^†P_AO = Percent of those with or without disease having airflow obstruction (LLN-2).

^‡N_AO = the number of U.S. individuals (in millions) with airflow obstruction (LLN-2).