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Table 1 Baseline demographics of the subjects on the study

From: Evidence for harm reduction in COPD smokers who switch to electronic cigarettes

  COPD Controls COPD E-Cig users Baseline P-value between groups
Agec 65.3 (±5.5) 66.9 (±6.7) 0.350
Sex 21 M, 3 F 20 M, 4 F -
COPD GOLD stage
 Stage 1 3 2 -
 Stage 2 5 6 -
 Stage 3 11 10 -
 Stage 4 5 6 -
post-BD FEV1b (L) 1.47 (1.13, 1.72) 1.25 (0.94, 1.78) 0.298
post-BD FVCb (L) 2.39 (2.1, 2.64) 2.37 (2, 2.65) 0.902
%FEV1/FVCc 56.2 (±10.3) 59.4 (±8.4) 0.244
Pack years of smokingc 51.7 (±9.9) 52.4 (±10.7) 0.365
Cig/dayc 20.5 (±3.3) 21.8 (±4.4) 0.228
CAT scoreb 20.5 (17.8, 24.3) 21.5 (17.8, 25.3) 0.710
COPD Exacerbationsa, c 2.1 (±1.1) 2.3 (±1) 0.440
Co-morbidities
 Respiratory failure 5 6  
 CHF 3 3  
 CHD 2 3  
 Hypertension 9 8  
 Diabetes 4 5  
 OSAS 6 3  
 Chronic Kidney Failure 1 0  
 Liver cirrhosis 1 0  
 Lung cancer 0 1  
 Pulmonary hypertension 0 1  
 GERD 3 2  
 Degenerative joint disease 2 4  
 Osteoporosis 2 1  
 Depression/Anxiety 2 4  
  1. Abbreviations: COPD Chronic obstructive pulmonary disease, M male, F female, BD bronchodilator, L litre, FEV1 forced expiratory volume in 1 s, FVC forced vital capacity, Cig conventional cigarettes, CAT COPD assessment tool, CHF chronic heart failure, CHD coronary heart disease, OSAS obstructive sleep apnoea syndrome, GERD Gastroesophageal reflux disease
  2. a COPD exacerbations in past 12 months
  3. b Median (interquartile range); c Mean (± standard deviation)