Table 1: Demographic and clinical characteristics of recruited patients.

Baseline Characteristics	Cases (N = 33)
Age (years)	56.61 ± 7.87
Gender Male/Female	26 (79%)/7 (21%)
Smoking status Current smokers/Ex-smokers/Passive smokers Smoking index [p/yr (mean ± SD)]	11 (33%)/15 (46%)/7 (21%) 40.25 ± 22.96
Type of smoking Cigarette smoking Water pipe smoking	24 (72.7%) 2 (6%)
Presence of co-morbidities Hypertension Diabetes Mellitus OSA Ischemic heart disease Others	24 (73%) 13 (37%) 7 (21%) 10 (30.3%) 3 (9.1%) 3 (9.1%)
Pulmonary hypertension; mPAP (mmHg)	23 (88.5%); 31.35 ± 6.45
Pulmonary function test: FEV1/ FVC FEV1 (L) FEV1% predicted	53.41 ± 10.45 1.23 ± 0.58 43.7 ± 18.2
History of exacerbation < 3 times/year; previous MN ≥ 3 times/year; previous MV	11 (33%); 3 (9%) 22 (67%); 6 (18%)

OSA: obstructive sleep apnea, p/yr: pack/year, mPAP: mean pulmonary artery pressure, FEV₁: forced expiratory volume in 1^st second, FEV₁/ FVC ratio: the forced expiratory volume in 1^st second / the forced vital capacity.