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Table 3 Baseline characteristics for the base case study population (categories based on Swanney prediction equations [6])

From: Lung function decline in relation to diagnostic criteria for airflow obstruction in respiratory symptomatic subjects

 

Total cohort

(n = 3,324)

Non-obstructed

(n = 2,406)

Discordant

(n = 389)

Obstructed

(n = 529)

p value

  

LLN*-Fixed-

LLN*-Fixed+

LLN* + Fixed+

 

Follow-up time, years (SD)

3.4 (1.4)

3.4 (1.4)

3.2 (1.4)

3.4 (1.5)

0.592

Males, n (%)

1,500 (45)

894 (37)

245 (63)

361 (68)

< 0.001

Age, mean (SD)

58.1 (11.0)

56.2 (10.5)

67.0 (10.1)

60.3 (10.2)

< 0.001

   40-49, n (%)

918 (28)

798 (33)

30 (8)

90 (17)

 

   50-59, n (%)

1,003 (30)

758 (31)

66 (17)

179 (34)

 

   60-69, n (%)

827 (25)

553 (23)

118 (30)

156 (29)

 

   70-79, n (%)

512 (15)

277 (12)

144 (37)

91 (17)

 

   > 80, n (%)

64 (2)

20 (1)

31 (8)

13 (3)

< 0.001

Height, m

1.69 (0.1)

1.68 (0.1)

1.73 (0.1)

1.70 (0.1)

< 0.001

BMI, kg/m [2] (SD)

27.5 (5.0)

28.2 (5.2)

27.0 (4.2)

25.0 (4.0)

< 0.001

Smoking status, n (%)

   Never

956 (29)

864 (36)

59 (15)

33 (6)

 

   Former

1,360 (41)

964 (40)

192 (49)

204 (39)

 

   Current

1,008 (30)

578 (24)

138 (36)

292 (55)

< 0.001

Respiratory medication use, n (%)

   Short-acting bronchodilators

1,436 (43)

1,061 (44)

147 (38)

228 (43)

0.066

   Long-acting bronchodilators

1,174 (35)

841 (35)

144 (37)

189 (36)

0.715

   Inhaled corticosteroids

1,972 (59)

1,550 (64)

185 (48)

237 (45)

< 0.001

FEV1

   Prebronchodilator, liters (SD)

2.28 (0.74)

2.46 (0.71)

2.02 (0.65)

1.64 (0.51)

< 0.001

as % predicted* (SD)

74.6 (17.9)

81.1 (14.5)

65.3 (12.1)

51.7 (12.8)

< 0.001

   Postbronchodilator, liters (SD)

2.46 (0.77)

2.63 (0.74)

2.21 (0.68)

1.85 (0.56)

< 0.001

as % predicted* (SD)

80.2 (17.4)

86.5 (14.1)

71.7 (12.3)

58.1 (13.2)

< 0.001

FVC

   Prebronchodilator, liters (SD)

3.23 (0.95)

3.22 (0.95)

3.24 (1.03)

3.26 (0.91)

0.708

   Postbronchodilator, liters (SD)

3.35 (0.96)

3.30 (0.95)

3.43 (1.03)

3.53 (0.92)

< 0.001

FEV1/FVC

   Prebronchodilator (SD)

0.71 (0.12)

0.77 (0.07)

0.63 (0.05)

0.51 (0.08)

< 0.001

   Postbronchodilator (SD)

0.74 (0.12)

0.80 (0.05)

0.65 (0.03)

0.52 (0.08)

< 0.001

  1. BMI: body mass index; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; LNN: lower limit of normal; SD: standard deviation
  2. * based on Swanney prediction equations [6]