Skip to main content

Table 1 Baseline characteristics of subjects included in versus excluded from the analysis

From: Comparison of the variability of the annual rates of change in FEV1 determined from serial measurements of the pre- versus post-bronchodilator FEV1 over 5 years in mild to moderate COPD: Results of the lung health study

 

Included in this analysis

Study Group

  

SIA

SIP

UC

No. of Subjects

N

457

459

487

 

Y

1504

1503

1477

Subject Characteristics

Gender

    

% Male

N

65.6

64.3

62.6

 

Y

59.3

63.9

64.2

  

p =0.0151

ns

ns

Age, y

    

Mean ± SD

N

48.7 ± 7.1

48.3 ± 6.9

48.6 ± 7.0

 

Y

48.3 ± 6.8

48.6 ± 6.8

48.4 ± 6.8

  

ns

ns

ns

Race

    

% White

N

92.8

94.8

95.3

 

Y

96.9

96.1

95.7

  

p =0.0001

ns

ns

FEV 1 , L – pre (S2)

    

Mean ± SD

N

2.62 ± 0.61

2.62 ± 0.58

2.59 ± 0.57

 

Y

2.62 ± 0.61

2.65 ± 0.60

2.66 ± 0.60

  

ns

ns

p =0.0178

FEV 1 , L– post (S2)

    

Mean ± SD

N

2.73 ± 0.63

2.73 ± 0.60

2.70 ± 0.59

 

Y

2.73 ± 0.64

2.76 ± 0.63

2.78 ± 0.63

  

ns

ns

p =0.0155

BMI, kg/ht 2

    

Mean ± SD

N

26.0 ± 4.1

25.7 ± 3.9

25.5 ± 4.1

 

Y

25.3 ± 3.9

25.7 ± 3.9

25.6 ± 3.9

  

p =0.002

ns

ns

Cigarettes/Day

    

Mean ± SD

N

32.6 ± 13.4

32.8 ± 12.8

31.8 ± 12.6

 

Y

30.8 ± 13.1

31.1 ± 12.5

30.9 ± 12.9

  

p =0.006

p =0.007

ns

Pack/Years

    

Mean ± SD

N

42.6 ± 21.7

41.9 ± 19.9

41.7 ± 20.6

 

Y

39.8 ± 19.0

39.9 ± 18.5

40.2 ± 18.3

  

p =0.027

ns

ns

O’Connor slope

    

Mean ± SD

N

−14.4 ± 28.1

−12.2 ± 24.1

−12.6 ± 21.6

 

Y

−13.2 ± 23.2

−12.0 ± 21.3

−12.9 ± 24.6

  

ns

ns

ns

  1. SIA = Special Intervention Anticholinergic; SIP = Special Intervention Placebo; UC = Usual Care; S2 = second screening visit.
  2. Differences for each measure between participants included versus not included in the analysis were tested using the t-test (for age, FEV1 and BMI), Chi-square (for gender and race) and Wilcoxon rank sum test (for cigarettes/day, pack-years and O’Connor slope).