Life expectancy and years of life lost in chronic obstructive pulmonary disease: Findings from the NHANES III Follow-up Study

Figures & data

Figure 1 Seventy scale for COPD.

Notes: Those who were diagnosed by a physician as having chronic bronchitis, emphysema, or asthma but did not have COPD or RLD according to the above criteria were classified as GOLD stage 0 (if they reported symptoms) or Normal (if they reported no symptoms). Persons who had a positive response to (a) having a cough for three consecutive months out of the year, (b) phlegm first-thing in the morning three consecutive months out of the year, or (c) wheezing in the past 12 months, were considered as having GOLD stage 0 if their pulmonary function testing did not indicate COPD or RLD.
Abbreviations: COPD, chronic obstructive pulmonary disease; GOLD, Global Initiative for Chronic Obstructive Lung Disease; FEV₁, forced expiratory volume in one second; FVC, forced vital capacity; RLD, restrictive lung disease.

Table 1 Demographics and description of key variables. All figures are column percentages except for counts (n, died) and age

	All	Current smoker	Former smoker	Never smoker
n	6,261	1,294	2,261	2,706
Died	1,873	413	751	709
Age (mean ± SD)
Male	67 ± 10	64 ± 9	69 ± 10	68 ± 11
Female	68 ± 11	63 ± 8	67 ± 10	69 ± 11
Male	48%	62%	67%	24%
Caucasian, non-Hispanic	57%	51%	64%	56%
No college education	77%	81%	75%	78%
COPD
Stage 3 or 4	3%	7%	4%	1%
Stage 2	12%	22%	14%	6%
Stage 1	16%	18%	19%	12%
Stage 0	14%	14%	14%	13%
RLD	8%	7%	7%	9%
Normal	48%	33%	43%	58%
Smoking status
Smoker	21%	100%
Former smoker	36%		100%
Never smoker	43%			100%
Pack-years
High (≥60)	10%	17%	18%
Medium (30–60)	16%	34%	25%
Low (1–30)	27%	44%	50%
BMI
Underweight (<18.5)	2%	5%	1%	2%
Normal weight (18.5–25)	31%	40%	28%	30%
Overweight (25–30)	40%	36%	43%	38%
Obese (>30)	27%	19%	28%	30%
Medical conditions (% yes)
Diabetes	14%	10%	16%	14%
Hypertension	43%	37%	44%	46%
CHF	7%	6%	9%	6%
Stroke	6%	5%	7%	5%
MI	9%	9%	13%	7%
Cancer (other than skin)	7%	5%	8%	7%

Abbreviations: BMI, body mass index; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; MI, myocardial infarction; RID, restrictive lung disease.

Figure 2 Kaplan–Meier survival curves of all 6,261 participants age 50 and over in NHANES III, stratified by lung function impairment.

Figure 3 Kaplan–Meier survival curves of 1,294 current smokers age 50 and over in NHANES III, stratified by lung function impairment.

Figure 4 Kaplan–Meier survival curves of 2,261 former smokers age 50 and over in NHANES III, stratified by lung function impairment.

Figure 5 Kaplan–Meier survival curves of 2,706 never smokers age 50 and over in NHANES III, stratified by lung function impairment.

Table 2 Excess deaths rates from Figures 2–5, relative to persons with no lung disease

Group	Smoking status
	All	Current	Former	Never
Normal	Reference	Group
Stage 0 (Symptoms only)	0.0098	0.0143	0.0128	0.0055
Restrictive lung disease	0.0174	0.0069	0.0292	0.0190
Stage 1	0.0190	0.0174	0.0223	0.0207
Stage 2	0.0310	0.0257	0.0366	0.0257
Stage 3 or 4	0.0884	0.1609	0.1484	0.0707

Table 3 Relative risks from multivariable Cox proportional hazards regressions models

Variablea	Smoking status
	All persons	Current	Former	Never
Male	1.3	1.6	1.2	1.2
Caucasian	1.0	0.9	1.0	1.0
No college education	1.2	0.9	1.3	1.2
Age
50–59	1.0	1.0	1.0	1.0
60–69	2.0	2.1	1.9	2.2
70–79	4.5	3.8	4.2	6.0
80+	11.6	8.6	9.5	17.9
COPD
Stage 3 or 4	2.6	2.7	3.0	1.8
Stage 2	1.4	1.4	1.5	1.5
Stage 1	0.9	1.0	0.9	0.9
Stage 0	1.2	1.4	1.2	1.1
RLD	1.3	1.3	1.4	1.2
Normal	1.0	1.0	1.0	1.0
Smoking status
Smoker	1.5
Former Smoker	1.0
Never Smoker	1.0
Pack-years history
High	1.3	1.3	1.2
Medium	1.1	1.2	1.1
Low	1.0	1.0	1.0
BMI
Underweight	1.7	1.8	2.0	1.5
Normal weight	1.0	1.0	1.0	1.0
Overweight	0.9	0.8	0.9	0.9
Obese	0.8	0.7	0.8	0.8
Medical conditions
Diabetes	1.7	1.8	1.5	2.0
Hypertension	1.2	1.4	1.1	1.3
CHF	1.3	1.2	1.2	1.5
Stroke	1.4	1.1	1.6	1.4
MI	1.2	1.4	1.3	1.0
Cancer	1.4	1.2	1.3	1.6
Baseline mortality rateb	0.0060	0.0103	0.0069	0.0041

a Notes: The respective reference groups for these relative risks are persons who are: female, non-Caucasian, college education, aged 50–59, no lung disease, never smoker (for the first model), low pack-years (for the first three models), normal weight, and without any of the specified medical conditions.

b This the mortality rate for persons in the reference group described immediately above. It is computed by setting the values of the covariates (variables) in the respective models equal to zero.

Abbreviations: BMI, body mass index; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; MI, myocardial infarction; RID, restrictive lung disease.

Table 4 Mortality rates for otherwise healthy 65-year-old Caucasian males based on the models of Table 3

Group	Smoking status
	All	Current	Former	Never
Normal	0.0153	0.0295	0.0151	0.0109
Stage 0 (Symptoms only)	0.0179	0.0400	0.0176	0.0120
Restrictive lung disease	0.0204	0.0383	0.0216	0.0132
Stage 1	0.0143	0.0308	0.0140	0.0096
Stage 2	0.0217	0.0424	0.0221	0.0164
Stage 3 or 4	0.0397	0.0787	0.0449	0.0196

Table 5 Excess death rates for otherwise healthy 65-year-old Caucasian males, computed as Table 4 less the mortality rates for males aged 65 in the general population (0.0186)

Group	Smoking status
	All	Current	Former	Never
Normal	−0.0033	0.0109	−0.0035	−0.0077
Stage 0 (Symptoms only)	−0.0007	0.0214	−0.0010	−0.0066
Restrictive lung disease	0.0018	0.0197	0.0030	−0.0054
Stage 1	−0.0043	0.0122	−0.0046	−0.0090
Stage 2	0.0031	0.0238	0.0035	−0.0022
Stage 3 or 4	0.0211	0.0601	0.0263	0.0010

Table 6 Mortality rates for otherwise healthy 65-year-old Caucasian females based on the models of Table 3

Group	Smoking status
	All	Current	Former	Never
Normal	0.0119	0.0190	0.0125	0.0089
Stage 0 (Symptoms only)	0.0138	0.0258	0.0146	0.0098
Restrictive lung disease	0.0158	0.0247	0.0179	0.0107
Stage 1	0.0111	0.0198	0.0116	0.0078
Stage 2	0.0168	0.0273	0.0183	0.0133
Stage 3 or 4	0.0307	0.0507	0.0373	0.0159

Table 7 Excess death rates for otherwise healthy 65-year-old Caucasian females, computed as Table 6 less the mortality rates for females aged 65 in the general population (0.0120)

Group	Smoking status
	All	Current	Former	Never
Normal	−0.0001	0.0070	0.0005	−0.0031
Stage 0 (Symptoms only)	0.0018	0.0138	0.0026	−0.0022
Restrictive lung disease	0.0038	0.0127	0.0059	−0.0013
Stage 1	−0.0009	0.0078	−0.0004	−0.0042
Stage 2	0.0048	0.0153	0.0063	0.0013
Stage 3 or 4	0.0187	0.0387	0.0253	0.0039

Table 8 Life expectancies for otherwise healthy 65-year-old Caucasian males, based on the rates in Tables 4 and 5. See also Figure 6

Group	Smoking status
	All	Current	Former	Never
Normal	17.2	14.3	17.3	17.8
Stage 0 (Symptoms only)	16.9	12.5	16.9	17.7
Restrictive lung disease	16.3	12.7	16.0	17.5
Stage 1	17.4	14.0	17.4	18.0
Stage 2	16.0	12.1	15.9	17.1
Stage 3 or 4	12.5	8.5	11.7	16.5

Figure 6 Male life expectancy at age 65, stratified by smoking status and severity of COPD (See Table 8).

Table 9 Life expectancies for otherwise healthy 65-year-old Caucasian females, based on the rates in Tables 6 and 7. See also Figure 7

Group	Smoking status
	All	Current	Former	Never
Normal	19.8	17.4	19.6	20.3
Stage 0 (Symptoms only)	19.1	15.6	18.8	20.1
Restrictive lung disease	18.4	15.9	17.7	20.0
Stage 1	19.9	17.2	19.8	20.5
Stage 2	18.1	15.2	17.6	19.3
Stage 3 or 4	14.5	11.3	13.3	18.4

Figure 7 Female life expectancy at age 65, stratified by smoking status and severity of COPD (See Table 9).