Prevalence of and risk factors for postoperative pulmonary complications after lung cancer surgery in patients with early-stage COPD

Figures & data

Table 1 Demographic characteristics of study patients

	Total (n=343)	Normal PFT (n=230)	Early COPD				P-value
			Total (n=113)	Group A (n=71)	Group B (n=42)	P-value
Sex, male	236 (68.8)	131 (57.0)	105 (92.9)	67 (94.4)	38 (90.5)	0.436	<0.001
Age, years	66.2 (27–84)	64 (27–84)	70.5 (51–84)	70.1 (53–84)	71.3 (51–81)	0.639	<0.001
BMI, kg/m^2	23.1 (3.0)	23.2 (3.0)	23.0 (3.1)	23.1 (2.8)	22.5 (3.6)	0.315	0.445
Smoking status
Never	128 (37.3)	117 (50.9)	11 (9.7)	6 (8.5)	5 (11.9)	0.475	<0.001
Ex-smoker	117 (34.1)	63 (27.4)	54 (47.8)	37 (52.1)	17 (40.5)
Current-smoker	98 (28.6)	50 (21.7)	48 (42.5)	28 (39.4)	20 (47.6)
Smoking pack-year	20.1 (0–224)	2.4 (0–120)	39.8 (0–224)	39.1 (0–224)	42.0 (0–110)	0.532	<0.001
Diabetes mellitus	68 (19.8)	44 (19.1)	24 (21.2)	19 (26.8)	5 (11.9)	0.062	0.645
Hypertension	128 (37.3)	81 (35.2)	47 (41.6)	31 (43.7)	16 (38.1)	0.562	0.251
Chronic liver disease	9 (2.6)	6 (2.6)	3 (2.7)	3 (4.2)	0 (0.0)	0.293	0.980
Chronic kidney disease	7 (2.0)	3 (1.3)	4 (3.5)	2 (2.8)	2 (4.8)	0.627	0.224
Post-TB lesions on CXR	40 (11.7)	21 (8.7)	19 (16.8)	11 (15.5)	8 (19.0)	0.625	0.037
ASA class, n (%)
1, 2	326 (95.0)	222 (96.5)	104 (92.0)	65 (91.5)	39 (92.9)	0.864	0.072
3, 4	17 (5.0)	8 (3.5)	9 (8.0)	6 (8.5)	3 (7.1)
Previous solid cancer Hx	50 (14.6)	35 (15.2)	15 (13.3)	12 (16.9)	3 (7.1)	0.140	0.632
Neoadjuvant CTx	6 (1.7)	5 (2.2)	1 (0.9)	1 (1.4)	0 (0.0)	1.000	0.668

Notes: Significant differences between patients with and without COPD were tested using chi-square or Fisher’s exact test. Data are represented as mean (SD), number (%) patients, or median (range). Group A, low risk and less symptoms; group B, low risk and more symptoms.

Abbreviations: ASA, American Society Anesthesiology; BMI, body mass index; CTx, chemotherapy; CXR, chest radiograph; Hx, history; PFT, pulmonary function test; SD, standard deviation; TB, tuberculosis.

Table 2 Preoperative evaluation: PFT, mMRC, CAT, and SGRQ questionnaire

	Total (n=343)	Normal PFT (n=230)	Early COPD				P-value
			Total (n=113)	Group A (n=71)	Group B (n=42)	P-value
PFT
FEV1, % pred	102.8 (17.8)	107.9 (17.1)	92.4 (14.4)	92.8 (13.5)	91.8 (15.9)	0.725	<0.001
FVC, % pred	100.1 (15.0)	98.3 (15.0)	103.7 (14.2)	102.8 (12.8)	105.2 (16.4)	0.387	0.002
FEV1/FVC (%)	72.3 (10.4)	77.9 (6.8)	60.9 (6.3)	61.7 (6.0)	59.7 (6.6)	0.106	<0.001
DLCO, % pred	94.2 (19.8)	95.8 (20.2)	91.0 (18.8)	92.6 (19.4)	88.2 (17.7)	0.229	0.034
mMRC scale ≥2	41 (12.0)	23 (10.0)	18 (15.9)	0 (0.0)	18 (42.9)	<0.001	0.115
CAT score ≥10	95 (27.7)	59 (25.7)	36 (31.9)	0 (0.0)	36 (85.7)	<0.001	0.246
SGRQ score
Symptom	19.0 (0.0–87.0)	16.5 (0.0–82.2)	23.5 (0.0–87.0)	18.4 (0.0–67.9)	25.8 (9.7–87.0)	<0.001	<0.001
Activity	23.3 (0.0–100.0)	21.8 (0.0–79.7)	23.4 (0.0–100.0)	17.8 (0.0–53.2)	42.4 (11.2–100.0)	<0.001	0.059
Impacts	4.6 (0.0–89.9)	4.6 (0.0–55.5)	4.5 (0.0–89.9)	3.3 (0.0–23.8)	10.7 (0.0–89.9)	<0.001	0.552
Total	13.1 (0.0–84.7)	12.5 (0.0–54.7)	14.7 (0.8–84.7)	10.5 (0.8–28.5)	25.4 (6.9–84.7)	<0.001	0.071
SGRQ total score ≥25	75 (21.9)	54 (23.5)	25 (22.1)	2 (2.8)	22 (52.4)	<0.001	0.968
Pathology staging (carcinoid, carcinosarcoma, neuroendocrine carcinoma)
IA/B	193 (56.3)	128 (55.6)	65 (57.5)	42 (59.2)	23 (54.7)	0.110	0.136
IIA/IIB	67 (19.5)	40 (17.5)	27 (23.9)	15 (21.1)	12 (28.6)
IIIA/IIIB	78 (22.7)	57 (24.7)	21 (18.6)	14 (19.7)	7 (16.7)
IV	5 (1.5)	5 (2.2)	0 (0.0)	0 (0.0)	0 (0.0)

Notes: Significant differences between patients with and without COPD were tested using chi-square or Fisher’s exact test. Data are represented as mean (SD), number (%) patients, or median (range). Group A, low risk and less symptoms; group B, low risk and more symptoms.

Abbreviations: CAT, COPD assessment test; DL_CO, diffusing capacity of the lung for carbon monoxide; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; mMRC, modified Medical Research Council; % pred, percentage of the predicted value; PFT, pulmonary function test; SD, standard deviation; SGRQ, St George Respiratory Questionnaire.

Figure 1 Flow diagram for patient recruitment.

Note: Group A, low risk and less symptoms; group B, low risk and more symptoms.
Abbreviations: FEV₁, forced expiratory volume in 1 second; % pred, percentage of the predicted value; PFT, pulmonary function test.

Table 3 Postoperative outcomes

	Total (n=343)	Normal PFT (n=230)	Early COPD				P-value
			Total (n=113)	Group A (n=71)	Group B (n=42)	P-value
PPCs	57 (16.6)	23 (10.0)	34 (30.1)	17 (23.9)	17 (40.5)	0.064	<0.001
Persistent air leak	30 (8.7)	15 (6.5)	15 (13.3)	9 (12.7)	6 (14.3)	0.807	0.037
Bacterial pneumonia	28 (8.2)	11 (4.8)	17 (15.0)	7 (9.9)	10 (23.8)	0.045	0.001
Atelectasis requiring BFS	8 (2.3)	4 (1.7)	4 (3.5)	3 (4.2)	1 (2.4)	1.000	0.299
Reintubation within 48 hours	5 (1.5)	5 (2.2)	0 (0.0)	0 (0.0)	0 (0.0)	–	0.176
Prolonged MV	4 (1.2)	4 (1.7)	0 (0.0)	0 (0.0)	0 (0.0)	–	0.306
Tracheostomy	3 (0.9)	3 (1.3)	0 (0.0)	0 (0.0)	0 (0.0)	–	0.554
AIP	1 (0.3)	1 (0.4)	0 (0.0)	0 (0.0)	0 (0.0)	–	1.000
Empyema	1 (0.3)	0 (0.0)	1 (0.9)	0 (0.0)	1 (2.4)	0.372	0.329
Hospital LOS, days	7.8 (3–157)	7.3 (3–157)	8.7 (4–37)	8.6 (4–34)	9.0 (5–37)	0.114	0.265
In-hospital death	3 (0.9)	3 (1.3)	0 (0.0)	0 (0.0)	0 (0.0)	–	0.554

Notes: Significant differences between patients with and without COPD were tested using chi-square or Fisher’s exact test. Data are represented as mean (SD), number (%) patients, or median (range). Group A, low risk and less symptoms; group B, low risk and more symptoms.

Abbreviations: AIP, acute interstitial pneumonia; BFS, bronchoscopy; LOS, length of stay; MV, mechanical ventilation; PFT, pulmonary function test; PPCs, postoperative pulmonary complications; SD, standard deviation.

Table 4 Multivariate analysis of risk factors for PPCs

Variable	OR	95% CI	P-value
All patients
COPD	3.42	1.775–6.596	<0.001
Post-TB lesion on CXR	2.73	1.178–6.345	0.019
BMI, kg/m^2	0.77	0.688–0.870	<0.001
DLCO, % pred	0.97	0.957–0.991	0.003
Operation time (minutes)	1.01	1.002–1.012	0.004
Patients with early COPD
BMI, kg/m^2	0.80	0.681–0.941	0.007
DLCO, % pred	0.97	0.944–0.996	0.024
Operation time (minutes)	1.01	1.004–1.018	0.003
Non-COPD patients
Post-TB lesion on CXR	4.43	1.248–15.690	0.021
Sex, male	3.39	1.059–10.858	0.040
BMI, kg/m^2	0.71	0.589–0.851	<0.001
DLCO, % pred	0.97	0.943–0.990	0.005

Abbreviations: BMI, body mass index; CXR, chest radiograph; DL_CO, diffusing capacity of the lung for carbon monoxide; OR, odds ratio; % pred, percentage of the predicted value; PPCs, postoperative pulmonary complications; TB, tuberculosis.

Table S1 Perioperative variables significantly associated with PPCs on univariate analysis

	Without PPCs, N=79	With PPCs, N=34	P-value
Patients with COPD
BMI, kg/m^2a	23.4 (2.5)	21.8 (4.1)	0.016
COPD subgroup Bb	25 (31.6)	17 (50.0)	0.064
DLCO, % preda	93.1 (19.6)	86.0 (16.2)	0.064
CAT scorec	5.9 (0–26)	7.4 (0–30)	0.059
SGRQ total score ≥25b	14 (17.7)	11 (32.4)	0.086
Operation time, minc	177.0 (70–375)	221.3 (107–375)	0.002
	N=207	N=23
Non-COPD patients
Sex, maleb	113 (54.6)	18 (78.3)	0.030
BMI, kg/m^2a	23.4 (2.8)	20.9 (15.6)	<0.001
Post-TB lesion on CXRb	15 (7.2)	6 (26.1)	0.003
DLCO, % preda	96.7 (20.1)	87.7 (19.7)	0.047
SGRQ scorec
Symptom	15.6 (0.0–82.2)	28.5 (6.7–58.7)	0.004
Activity	19.0 (0.0–79.7)	29.4 (0.0–75.0)	0.034
Impact	4.6 (0.0–55.5)	6.4 (0.0–44.4)	0.053
Total	12.4 (0.0–54.7)	18.9 (1.0–51.5)	0.010
SGRQ total score ≥25b	40 (19.3)	10 (43.5)	0.008

Note: Significant differences between with and without PPCs were tested using chi-square, or Fisher’s exact test. Data shown as

a mean (SD),

b number (%) patients, or

c median (range).

Abbreviations: BMI, body mass index; CAT, COPD assessment test; CXR, chest radiograph; DL_CO, diffusing capacity of the lung for carbon monoxide; % pred, percentage of the predicted value; PPCs, postoperative pulmonary complications; SGRQ, St George Respiratory Questionnaire; TB, tuberculosis.