Annual Body Weight Change and Prognosis in Chronic Obstructive Pulmonary Disease

Figures & data

Table 1 Characteristics of Subjects in the Hokkaido COPD and Kyoto University Cohorts

	Hokkaido COPD Cohort	Kyoto University Cohort	P-value
	(Discovery)	(Validation)
Patients, n	279	247
Age, years	69.4 ± 7.9	70.0 ± 8.4	0.46
Female, N (%)	17 (6.1%)	23 (9.3%)	0.19
Height, cm	162.9 ± 6.7	163.7 ± 6.8	0.15
Body mass index, kg/m^2	22.3 ± 3.2	22.1 ± 2.9	0.40
GOLD stage 1/2/3/4	72/126/68/13	51/115/69/12	0.53
Pack-years	62.6 ± 30.1	64.8 ± 34.2	0.44
FEV1, % predicted	64.5 ± 21.8	60.6 ± 20.2	0.04
FVC, % predicted	100.5 ± 18.9	96.0 ± 17.2	0.005
FEV1/FVC, %	51.2 ± 12.7	50.5 ± 13.5	0.57
DLCO, % predicted	77.1 ± 25.0	83.1 ± 29.4	0.01
KCO, % predicted	63.2 ± 23.9	65.5 ± 24.0	0.27
CT emphysema score	1.2 (0.7–2.2)	Not assessed
%LAV	25.4 ± 14.8 (n = 156)	28.4 ± 9.3	0.01

Notes: Data are shown as the mean ± standard deviation (SD), median (interquartile range), or number (%). P-values were obtained using the Fisher’s exact test, Student’s t-test, or the Mann–Whitney U-test, as appropriate.

Abbreviations: GOLD, Global Initiative for Chronic Obstructive Lung Disease; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; DL_CO, carbon monoxide diffusion capacity; K_CO, carbon monoxide transfer coefficient; CT, computed tomography; %LAV, per cent low attenuation volume.

Table 2 Characteristics of Groups Divided by Annual Weight Change in the Hokkaido COPD Cohort

	Weight Loss Group	No Change Group	Weight Gain Group	P-value
	(n = 70)	(n = 139)	(n = 70)
Age, years	71.6 ± 6.8	69.0 ± 8.5	68.1 ± 7.1	0.02
Female, N (%)	5 (7.1%)	10 (7.2%)	2 (2.9%)	0.49
Height, cm	162.9 ± 6.4	162.6 ± 7.1	163.4 ± 6.0	0.73
Body mass index, kg/m^2	22.1 ± 3.1	22.3 ± 3.2	22.5 ± 3.5	0.78
GOLD stage 1/2/3/4	13/29/24/4	39/60/34/6	20/37/10/3	0.15
Pack-years	61.5 ± 27.6	63.6 ± 33.4	61.8 ± 25.4	0.87
FEV1, % predicted	60.5 ± 22.0	65.2 ± 22.6	67.1 ± 19.9	0.17
FVC, % predicted	97.3 ± 19.5	101.0 ± 19.0	102.8 ± 17.8	0.20
FEV1/FVC, %	49.4 ± 13.1	51.3 ± 12.7	52.8 ± 12.2	0.27
DLCO, % predicted	74.2 ± 26.8	75.9 ± 24.1	82.3 ± 24.5	0.11
KCO, % predicted	64.0 ± 25.7	61.3 ± 22.8	66.2 ± 24.1	0.37
CT emphysema score	1.3 (0.7–2.3)	1.3 (0.7–2.2)	1.0 (0.5–1.7)	0.11
Annual decline in FEV1, mL/yr	25.3 ± 23.2	27.9 ± 23.6	37.4 ± 25.7	0.006
Annual decline in the rate*, %/yr	1.8 ± 2.1	2.2 ± 1.6	2.2 ± 1.7	0.24
Exacerbation, events/yr	0.2 ± 0.3	0.2 ± 0.5	0.2 ± 0.3	0.55

Notes: *Rate of FEV ₁ to baseline FEV₁ (%). Data are shown as the mean ± standard deviation (SD), median (interquartile range), or number (%). P-values were obtained using the Fisher’s exact test, one-way analysis of variance, or the Kruskal–Wallis test, as appropriate.

Abbreviations: GOLD, Global Initiative for Chronic Obstructive Lung Disease; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; DL_CO, carbon monoxide diffusion capacity; K_CO, carbon monoxide transfer coefficient; CT, computed tomography.

Figure 1 Distribution of annual body weight change in the Hokkaido COPD cohort study.

Figure 2 Kaplan–Meier curves based on groups divided by annual weight change in Hokkaido COPD cohort study. (A) All-cause mortality. (B) Patients who survived during the first 5 years. (C) Patients excluding death from malignancy.

Table 3 Multivariable Cox Proportional Hazards Analysis of All-Cause Mortality in the Hokkaido COPD and Kyoto University Cohorts

Variables	Hokkaido COPD Cohort		Kyoto University Cohort
	Hazard Ratio (95% CI)	P-value	Hazard Ratio (95% CI)	P-value
Model 1
Annual body weight change, kg/yr	0.52 (0.32–0.85)	0.01	0.47 (0.25–0.88)	0.02
Age, years	1.11 (1.07–1.14)	<0.001	1.07 (1.03–1.11)	<0.001
Model 2
Annual body weight change, kg/yr	0.55 (0.34–0.90)	0.02	0.43 (0.22–0.82)	0.01
Age, years	1.11 (1.07–1.15)	<0.001	1.05 (1.01–1.09)	0.01
Sex, male	2.47 (0.92–10.10)	0.08	3.12 (0.91–19.6)	0.07
Body mass index, kg/m^2	0.91 (0.85–0.97)	0.005	0.92 (0.82–1.03)	0.16
Pack-years	0.99 (0.99–1.0005)	0.06	1.00 (0.99–1.01)	0.95
FEV1, L	1.02 (0.73–1.44)	0.90	0.68 (0.37–1.22)	0.20
CT emphysema score	1.33 (1.07–1.65)	0.01	-	-
%LAV	-	-	1.04 (1.00–1.08)	0.07

Note: The hazard ratio was derived from the multivariate Cox proportional hazards models.

Abbreviations: FEV₁, forced expiratory volume in 1 second; CT, computed tomography; %LAV, per cent low attenuation volume.

Table 4 Causes of Death in the Hokkaido COPD and Kyoto University Cohorts

	Hokkaido COPD Cohort			Kyoto University Cohort
	Weight Loss Group	No Change Group	Weight Gain Group	Weight Loss Group	No Change Group	Weight Gain Group
Respiratory disease	19 (51.4)	17 (31.5)	9 (42.9)	14 (31.8)	6 (66.7)	1 (33.3)
Malignancy	14 (37.8)	21 (38.9)	7 (33.3)	10 (22.7)	2 (22.2)	2 (66.7)
Cardiovascular disease	1 (2.7)	6 (11.1)	5 (23.8)	14 (31.8)	0 (0.0)	0 (0.0)
Others	3 (8.1)	10 (18.5)	0 (0.0)	6 (13.6)	1 (11.1)	0 (0.0)

Notes: Data are shown as the number (%). P-values were 0.04 (Hokkaido COPD cohort) and 0.15 (Kyoto University cohort) by the Fisher’s exact test.

Table 5 Characteristics of Groups Divided by Annual Weight Change in the Kyoto University Cohort

	Weight Loss Group	No Change Group	Weight Gain Group	P-value
	(n = 154)	(n = 65)	(n = 28)
Age, years	70.9 ± 8.3	68.6 ± 7.5	67.7 ± 9.9	0.06
Female, N (%)	13 (8.4)	4 (6.2)	6 (21.4)	0.07
Height, cm	163.3 ± 7.1	164.7 ± 6.1	164.1 ± 6.7	0.36
Body mass index, kg/m^2	22.0 ± 3.0	22.3 ± 2.9	22.2 ± 2.6	0.75
GOLD stage 1/2/3/4	27/68/50/9	15/35/15/0	9/12/4/3	0.03
Pack-years	63.4 ± 32.5	70.5 ± 40.5	58.9 ± 24.9	0.24
FEV1, % predicted	58.1 ± 19.6	64.8 ± 18.6	65.3 ± 24.2	0.03
FVC, % predicted	94.8 ± 16.9	97.6 ± 16.1	99.3 ± 20.8	0.30
FEV1/FVC, %	48.8 ± 13.1	53.9 ± 12.9	52.4 ± 16.1	0.03
DLCO, % predicted	81.6 ± 30.9	89.3 ± 27.0	77.5 ± 25.0	0.11
KCO, % predicted	63.6 ± 24.3	71.2 ± 24.2	62.7 ± 20.0	0.08
%LAV	29.3 ± 9.6	26.2 ± 8.4	28.6 ± 9.3	0.07
Annual decline in FEV1, mL/yr	31.7 ± 24.8	36.4 ± 27.8	37.6 ± 27.8	0.33
Annual decline in the rate*, %/yr	2.1 ± 2.1	2.2 ± 2.3	1.9 ± 3.1	0.78
Exacerbation, events/yr	0.5 ± 0.7	0.3 ± 0.5	0.3 ± 0.3	0.08

Notes: * Rate of FEV ₁ to baseline FEV₁ (%). Data are shown as the mean ± standard deviation (SD), median (interquartile range), or number (%). P-values were obtained using the Fisher’s exact test, one-way analysis of variance, or the Kruskal–Wallis test, as appropriate.

Abbreviations: GOLD, Global Initiative for Chronic Obstructive Lung Disease; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; DL_CO, carbon monoxide diffusion capacity; K_CO, carbon monoxide transfer coefficient; %LAV, per cent low attenuation volume.

Figure 3 Kaplan–Meier curves based on groups divided by annual weight change in Kyoto University cohort. (A) All-cause mortality. (B) Patients who survived during the first 5 years. (C) Patients excluding death from malignancy.

Table 6 Relative Risk for Weight Loss Group versus Others Using Logistic Regression Analysis

	Odds Ratio (95% CI)	P-value
Age, years	1.03 (1.01–1.06)	0.005
Sex, male	0.69 (0.34–1.40)	0.30
Body mass index, kg/m^2	1.00 (0.93–1.07)	0.93
Smoking status, pack-years	1.00 (0.99–1.005)	0.82
FEV1, % predicted	0.99 (0.98–1.006)	0.26
FVC, % predicted	0.99 (0.98–1.007)	0.28
KCO, % predicted	1.00 (0.99–1.01)	0.88
Annual decline in FEV1, mL/yr	1.00 (0.99–1.003)	0.23
Exacerbation frequency, events/yr	1.51 (1.02–2.23)	0.03

Note: The odds ratio was derived from the logistic regression analysis.

Abbreviations: FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; K_CO, carbon monoxide transfer coefficient.