Table 1 Baseline characteristics according to the aetiology of pleural effusion

Height (cm)

164.9 ± 10.0

161.5 ± 9.6

161.4 ± 17.2

161.0 ± 9.0

164.5 ± 6.5

< 0.001

Body weight (kg)

61.0 ± 12.2

59.9 ± 10.8

60.5 ± 11.2

57.5 ± 11.9

60.0 ± 10.1

0.054

Age (years)

66.1 ± 14.4

65.9 ± 12.3

61.3 ± 18.0

74.0 ± 11.9

63.0 ± 14.6

< 0.001

Sex

< 0.001

Male

269 (77.5%)

622 (54.6%)

129 (56.3%)

70 (51.5%)

136 (74.3%)

Female

68 (19.6%)

448 (39.3%)

63 (27.5%)

53 (39.0%)

38 (20.8%)

Laboratory findings (CBC)

WBC (10³/uL)

12.9 ± 6.8

8.9 ± 4.4

7.1 ± 2.4

8.0 ± 4.5

9.7 ± 16.4

< 0.001

Haemoglobin (g/dL)

11.4 ± 2.0

12.6 ± 1.9

12.6 ± 2.0

11.2 ± 2.2

12.3 ± 2.3

< 0.001

MCV (fl.)

91.5 ± 6.6

91.6 ± 5.4

90.4 ± 6.3

93.7 ± 6.6

90.8 ± 6.4

< 0.001

MCH (pg)

30.2 ± 2.6

30.3 ± 2.1

30.0 ± 2.4

30.7 ± 2.6

30.0 ± 2.6

0.013

PDW (fl.)

10.7 ± 2.5

10.6 ± 1.9

10.4 ± 2.4

11.7 ± 3.1

10.6 ± 1.7

< 0.001

Haematocrit (%)

34.4 ± 5.7

37.9 ± 5.4

37.9 ± 5.4

34.1 ± 6.4

37.3 ± 6.7

< 0.001

Platelet (10³/uL)

305.3 ± 136.1

295.2 ± 108.3

302.6 ± 103.8

197.4 ± 103.8

265.0 ± 110.3

< 0.001

Laboratory findings (Chemical)

ALT¹

28.5 ± 28.2

23.4 ± 38.0

25.0 ± 31.6

36.6 ± 81.8

26.5 ± 48.1

0.006

AST¹

32.1 ± 26.3

29.2 ± 51.4

28.1 ± 22.8

44.9 ± 58.1

30.2 ± 38.1

0.003

Alkaline phosphatase¹

117.6 ± 74.3

109.5 ± 160.0

90.4 ± 50.4

103.2 ± 68.8

109.2 ± 220.7

0.264

Total bilirubin (mg/dL)

0.9 ± 1.2

0.6 ± 0.4

0.6 ± 0.3

1.1 ± 1.5

0.6 ± 0.6

< 0.001

Glucose (mg/dL)

145.0 ± 62.4

133.5 ± 54.7

126.9 ± 58.6

141.2 ± 71.1

128.7 ± 48.6

0.001

Albumin (g/dL)

2.6 ± 0.6

3.1 ± 0.6

3.2 ± 0.5

2.9 ± 0.6

3.1 ± 0.7

< 0.001

Total protein (g/dL)

6.3 ± 0.9

6.5 ± 0.7

6.8 ± 0.8

6.3 ± 1.0

6.5 ± 0.9

< 0.001

Creatinine (mg/dL)

1.2 ± 1.5

0.9 ± 0.8

0.9 ± 0.5

1.5 ± 1.6

1.1 ± 1.3

< 0.001

BUN (mg/dL)

18.3 ± 12.7

15.8 ± 9.4

14.0 ± 8.3

23.3 ± 15.0

16.0 ± 8.8

< 0.001

LD¹

222.8 ± 81.1

309.5 ± 366.5

220.4 ± 78.8

288.8 ± 108.9

240.1 ± 113.0

< 0.001

CRP (mg/dL)

14.7 ± 9.8

4.3 ± 5.9

6.3 ± 6.0

3.1 ± 4.9

4.9 ± 6.3

< 0.001

Procalcitonin (ng/mL)

3.3 ± 10.3

1.1 ± 5.8

0.3 ± 0.8

1.3 ± 3.2

0.7 ± 3.0

0.002

Calcium (mg/dL)

8.4 ± 0.6

8.9 ± 0.7

8.7 ± 0.6

8.5 ± 0.7

8.6 ± 0.7

< 0.001

Sodium (mmol/L)

136.2 ± 4.5

137.8 ± 4.2

137.1 ± 3.8

136.9 ± 4.8

137.8 ± 3.7

< 0.001

Chloride (mmol/L)

99.9 ± 5.2

100.9 ± 4.5

101.2 ± 4.2

101.1 ± 6.6

101.5 ± 3.9

0.001

Potassium (mmol/L)

4.2 ± 0.6

4.3 ± 0.5

4.2 ± 0.4

4.2 ± 0.6

4.3 ± 0.5

0.01

Phosphorus (mg/dL)

3.2 ± 0.9

3.5 ± 0.7

3.3 ± 0.6

3.4 ± 0.9

3.4 ± 0.9

< 0.001

D-dimer (ug/ml)

4.4 ± 6.2

4.6 ± 6.3

4.2 ± 4.2

4.4 ± 6.7

3.0 ± 4.4

0.324

BNP (pg/mL)

251.3 ± 455.4

138.4 ± 318.5

193.8 ± 421.6

845.4 ± 1253.9

222.1 ± 764.5

< 0.001

Pleural fluid chemical

ADA¹

90.7 ± 141.5

28.6 ± 50.9

88.3 ± 54.4

11.8 ± 8.8

34.4 ± 29.1

< 0.001

LD¹

4919.5 ± 10686.8

1074.2 ± 5184.3

727.1 ± 1864.9

149.1 ± 309.0

802.7 ± 1257.3

< 0.001

Albumin (g/dL)

2.0 ± 0.8

2.6 ± 0.7

2.7 ± 0.6

1.4 ± 0.6

2.3 ± 0.7

< 0.001

Total protein (g/dL)

4.1 ± 1.3

4.4 ± 1.0

4.9 ± 1.0

2.5 ± 1.0

4.3 ± 1.2

< 0.001

Glucose (mg/dL)

89.2 ± 80.8

109.9 ± 54.9

101.5 ± 48.8

156.8 ± 63.3

106.6 ± 57.1

< 0.001

pH

7.2 ± 0.3

7.3 ± 0.2

7.3 ± 0.2

7.4 ± 0.1

7.3 ± 0.2

< 0.001

Pleural fluid cell count

Nucleated cells (/uL)

31.90 ± 85.5

6.20 ± 4.12

6.73 ± 22.40

1.12 ± 2.31

6.10 ± 15.82

< 0.001

RBC (/uL)

59.61 ± 261.43

70.82 ± 270.61

48.34 ± 322.84

40.37 ± 282.84

255.62 ± 694.30

< 0.001

Histiocyte (%)

14.3 ± 15.8

27.9 ± 19.5

18.2 ± 14.5

44.0 ± 21.4

25.0 ± 20.6

< 0.001

Neutrophil (%)

65.2 ± 33.0

18.2 ± 24.4

18.5 ± 23.8

15.4 ± 21.6

30.6 ± 30.3

< 0.001

Lymphocyte (%)

19.3 ± 22.8

39.2 ± 25.5

63.3 ± 25.7

37.5 ± 21.7

34.5 ± 28.3

< 0.001

Eosinophil (%)

3.9 ± 6.0

5.4 ± 8.0

5.8 ± 9.6

7.5 ± 15.0

17.1 ± 24.7

< 0.001

Basophil (%)

1.5 ± 1.1

1.5 ± 1.1

1.5 ± 1.4

1.9 ± 1.8

1.7 ± 1.3

0.473

Mesothelial cell (%)

4.5 ± 6.0

4.0 ± 4.7

2.8 ± 2.9

3.7 ± 4.5

4.1 ± 5.1

0.087

Complicated pleural effusion

< 0.001

False

276 (79.5%)

1100 (96.6%)

223 (97.4%)

136 (100.0%)

176 (96.2%)

True

71 (20.5%)

39 (3.4%)

6 (2.6%)

0 (0.0%)

7 (3.8%)