COPD is commonly underdiagnosed in patients with lung cancer: results from the RECOIL study (retrospective study of COPD infradiagnosis in lung cancer)

Figures & data

Figure 1 Study design.

Table 1 Characteristics of patients with coexisting COPD and lung cancer

Variables	Total (n=80)
Sex, n (%)
Men	61 (76.2)
Women	19 (23.8)
Age, mean (SD), years	70.7 (9.3)
BMI, mean (SD), kg/m^2	25.9 (5.1)
Pack-years (IQR)	52 (45–76)
Emphysema, n (%)	60 (75)
GOLD stage, n (%)
A	34 (42.5)
B	24 (30)
C	7 (8.8)
D	15 (18.8)
Baseline lung function
FEV1 %, mean (SD)	57.8 (17.6)
FEV1/FVC%, mean (SD)	53.1 (10.1)
DLCO%, mean (SD)	68.0 (21.6)
Histology, n (%)
Adenocarcinoma	33 (42.9)
Squamous cell	33 (42.9)
Small cell	6 (7.8)
Neuroendocrine	1 (1.3)
Large cell	2 (2.6)
Poorly differentiated	2 (2.6)
Lung cancer stage, n (%)
Ia	10 (13.7)
Ib	10 (13.7)
IIa	4 (5.5)
IIb	12 (16.4)
IIIa	7 (9.6)
IIIb	13 (17.8)
IV	16 (21.9)
Unknown	1 (1.4)
Mortality, n (%)	46 (57.5)

Abbreviations: BMI, body mass index; DLCO, diffusing capacity of the lungs for carbon monoxide; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; GOLD, Global Initiative for Chronic Obstructive Lung Disease; IQR, interquartile range; SD, standard deviation.

Table 2 Characteristics of patients with coexisting COPD and lung cancer by group

Variables	COPD unknown (n=48)	COPD known (n=32)	P-value
Sex M/F, %	69/31	88/12	0.096
Age, mean (SD), years	68.9 (9.3)	73.4 (8.8)	0.034
Emphysema, n (%)	31 (64.6)	29 (90.6)	0.018
GOLD stage, n (%)			0.102
A	24 (50.0)	10 (31.2)
B	14 (29.2)	10 (31.2)
C	5 (10.4)	2 (6.2)
D	5 (10.4)	10 (31.2)
FEV1 %, mean (SD)	70.7 (13.1)	54.6 (17.3)	0.044
DLCO%, mean (SD)	72.4 (21.6)	58.6 (18.8)	0.013
Outpatient visits (n), mean (SD)	30.4 (22.1)	20.2 (16.1)	0.029
Histology (adenocarcinoma/squamous), %	48/39	36/48	0.569
Lung cancer stage (%)			0.013
Ia	6.8	24.1
Ib	6.8	24.1
IIa	2.3	10.3
IIb	15.9	17.2
IIIa	13.6	3.4
IIIb	25.0	6.9
IV	27.3	13.8
Mortality (%)	58.3	56.2	0.891

Abbreviations: DLCO, diffusing capacity of the lungs for carbon monoxide; F, female; FEV₁, forced expiratory volume in 1 second; GOLD, Global Initiative for Chronic Obstructive Lung Disease; M, male; SD, standard deviation.

Table 3 Stage distribution by group and adjusted mortality

Stage	Group A	Group B
I	14 (48%)	6 (14%)
II	8 (28%)	8 (19%)
III	3 (10%)	17 (39%)
IV	4 (14%)	12 (28%)
Variables	Unadjusted		Adjusted
	HR (95% CI)	P-value	HR (95% CI)	P-value
COPD	1.16 (0.60–2.21)	0.660	1.87 (0.91–3.85)	0.087
Stage II			1.51 (0.54–4.24)	0.435
Stage III			2.32 (0.87–6.16)	0.091
Stage IV			5.21 (1.90–14.2)	0.001

Note: Group A, patients with lung cancer and pre-existing COPD; Group B, patients with lung cancer and COPD who were diagnosed of both simultaneously.

Abbreviations: HR, hazard ratio; CI, confidence interval.

Figure 2 Survival of patients with coexisting COPD and lung cancer.