Supplementary table 2. Comparison of clinical features between SSP patients with (n=429) and without surgical intervention (n=388).
Variables

Surgery (+) (n=429)

Surgery (-) (n=388)

Mode of onset
first/recurrence/unknown

229 (53.4)/200 (46.6)/0 (0)254 (65.5)/132 (34)/2 (0.5)

Underlying pulmonary disease
Chronic obstructive pulmonary disease
Interstitial pneumonia
Combined pulmonary fibrosis and emphysema
Pulmonary malignancy
Pulmonary infection
CatamenialOthers

242 (56.8)
43 (10)37 (8.6)
48 (11.2)
21 (4.9)53 (12.4)
70 (16.3)

196 (50.5)
84 (21.6)
31 (8)
48 (12.4)
64 (16.5)
23 (5.9)57 (14.7)

Home oxygen therapy+/Comorbidities except for pulmonary disease+/-/unknown

p-value
0.00040.0786<0.00010.80000.6640<0.0001
0.00160.56200.000231 (7.2)/398 (92.8)

60 (15.5)/328 (84.5)<0.0001255 (59.4)/173 (40.3)/1 (0.2)

287 (74)/101 (26)/0 (0)Details of comorbidities except for pulmonary disease
Impaired liver function（Child-Turcotte classification≧B）
Hemodialysis
Ischemic heart disease
Malignancy（treated within 5 years）
Cerebrovascular disease
Diabetes mellitus
Anemia（Hb≦8g/dl）
Autoimmune disorder
Arrhythmia
Hypertension
OthersAdministration of steroid on admission+/-

1 (0.2)9 (2.3)0.00831 (0.2)28 (6.5)
48 (11.2)
26 (6.1)
49 (11.4)
3 (0.7)19 (4.4)
27 (6.3)
101 (23.5)
132 (31)6 (1.5)44 (11.3)
63 (16.2)
60 (15.5)
56 (14.4)
6 (1.5)17 (4.4)
41 (10.6)
143 (36.9)
142 (36.7)

0.05770.01850.0407<0.00010.21000.322010.0310<0.00010.0881
0.051536 (8.4)/393 (91.6)

49 (12.6)/339 (87.4)

Affected side
left/right/bilateral

0.0734420 (97.9)/9 (2.1)

371 (95.6)/17 (4.4)

Age, median (IQR), years

66 (13-93)

74 (16-96)

GenderFemale/Male112 (26.1)/317 (73.9)

98 (25.3)/290 (74.7)<0.0001

0.8100Performance Status01

244 (56.9)
98 (22.8)

114 (29.4)
113 (29.1)

0.00010.045443 (10)25 (5.8)9 (2.1)
10 (2.3)

73 (18.8)
48 (12.4)
30 (7.7)
10 (2.6)0.00040.00130.00020.8250

BMI, median (IQR),

19.8 (12.5-32.9)

19 (10-33.9)

0.0001

Smoking index, median (IQR), pack x year

30 (0-175)

33.9 (0-158)

0.288

Serum CRP on admission, median (IQR), g/dl

0.3 (0-24.7)

0.8 (0-29.9)<0.0001

Serum albumin on admission, median (IQR), g/dl

4 (2-5.2)

3.7 (1.6-5.1)<0.0001

Degree of the collapsed lung
mild/moderate/severe/unknown

72 (16.8)/207 (48.3)/134 (31.2)/16 (3.7)

91 (23.5)/227 (58.5)/66 (17)/4 (1)<0.0001

234unknown

Thoracography+/Chest tube drainage+/-

0.518037 (8.6)/392 (91.4)

28 (7.2)/360 (92.8)
0.5230356 (83)/73 (17)315 (81.2)/73 (18.8)

Pleurodesis+/-

49 (11.4)/380 (88.6)

90 (23.2)/298 (76.8)

Administrative agents in the pleurodesis
OK-432
Minocycline
Autoblood

19 (4.4)
15 (3.5)
13 (3)

32 (8.3)
26 (6.7)
26 (6.7)

0.02920.03780.02038 (1.9)25 (5.8)8 (1.9)6 (1.6)25 (6.5)
9 (2.3)0.79300.77100.8070

Talk
Glucose solution
OthersTrans-airway procedure+/-<0.00010.290015 (3.5)/414 (96.5)

8 (2.1)/380 (97.9)

Treatment in intensive care unit+/-/unknown

88 (20.5)/338 (78.8)/3 (0.7)

14 (3.6)/374 (96.4)/0 (0)Total hospitalization, median (IQR), days

14 (4-234)

13 (0-136)

Outcome at discharge
home/transferred to other hospital/death<0.0001

0.0056<0.0001387 (90.2)/32 (7.5)/10 (2.3)

303 (78.1)/53 (13.7)/32 (8.2)

SSP: secondary spontaneous pneumothorax, Hb: hemoglobin, IQR: interquartile range, BMI: body mass index, CRP: c-reactive protein