Table 1 Patient characteristics and types of pleural effusion (N = 59)

Sociodemographic Variables

 Age (in years), mean (SD)

44.39 (20.91)

35.8

(21.4)

53.9

(15.8)

 < 0.001

 Cigarette smoked (pack year), mean (SD)

22.77 (10.1)

18.5

(11.2)

25.8

(8.3)

0.045

 Gender

0.9

  Female

40

(67.8%)

21

(52.5%)

19

(47.5%)

  Male

19

(32.2%)

10

(52.6%)

9

(47.4%)

 Religion

0.09

  Islam

56

(94.9%)

28

(50.0%)

28

(50.0%)

  Other

3

(5.1%)

3

(100.0%)

 Smoking History

0.2

  Non-smoker

28

(47.5%)

18

(64.3%)

10

(35.7%)

  Ex-Smoker

6

(10.2%)

2

(33.3%)

4

(66.7%)

  Smoker

25

(42.4%)

11

(44.0%)

14

(56.0%)

 Residence

0.003

  Rural

30

(50.8%)

10

(33.3%)

20

(66.7%)

  Urban

29

(49.2%)

21

(72.4%)

8

(27.6%)

Clinical Features

 Weight loss

52

(88.1%)

28

90.3

24

85.7

0.585

 Cough

52

(88.1%)

24

77.4

28

100.0

0.007

 Fever

34

(57.6%)

31

100.0

3

10.7

0.001

 Chest pain

34

(57.6%)

10

32.3

24

85.7

0.001

 Hemoptysis

16

(27.1%)

3

9.7

13

46.4

0.002

 Lymphadenopathy

7

(11.9%)

  No

31

100.0

21

75.0

0.012

  Yes

0

0.0

7

25

Laboratory Parameters

 PF WBC total count (cell/cmm), median (IQR)

300.0 (85.0–1400.0)

750.0 (200.0–1850.0)

155.0 (57.5–387.0)

0.008

 Cellular predominance

  Lymphocyte

52

(88.1%)

27

87.1

25

89.3

0.795

  Neutrophil

7

(11.9%)

4

12.9

3

10.7

 PF ADA (U/L), median (IQR)

40.0 (17.2–60.0)

57.0 (43.6–75.0)

17.1 (12.1–22.6)

 < 0.001

 Serum CRP (mg/L), median (IQR)

30.0 (15.7–51.7)

30.0 (18.2–34.7)

34.0 (14.3–64.0)

0.316

 PF ADA to serum CRP ratio, median (IQR)

1.38 (0.49–2.32)

2.16 (1.49–3.35)

0.48 (0.24–1.14)

 < 0.001