Figures (1)  Tables (4)

    • Figure 1. 

      Flowchart of patient inclusion.

    • Total Never smokers Ever smokers
      < 40 pack-years      		 Ever smokers
      ≥ 40 pack-years      		 p
      N (%) 4,336 1,175 (27.1) 1,527 (35.2) 1,634 (35.7)
      Male (%) 3,399 (78.4) 573 (48.8) 1271 (83.2) 1,555 (95.2) < 0.001
      Age, M (IQR) 72 (64, 79) 75 (67, 82) 72 (64, 79) 69 (63, 77) < 0.001
      Comorbidity, n (%)
      Asthma 618 (14.3) 195 (16.6) 222 (14.5) 201 (12.3) 0.005
      Interstitial lung disease 142 (3.3) 31 (2.6) 484 (3.1) 63 (4.9) 0.190
      Coronary heart disease 1067 (24.6) 301 (25.6) 375 (24.6) 397 (23.9) 0.591
      Congestive heart failure 878 (20.2) 272 (23.1) 300 (19.6) 306 (18.7) 0.012
      Cerebral vascular disease 624 (14.4) 198 (16.9) 216 (14.1) 210 (12.9) 0.011
      Diabetes 819 (18.9) 260 (22.1) 272 (17.8) 287 (17.6) < 0.004
      Cancer 225 (5.2) 35 (3.0) 89 (5.8) 101 (6.2) < 0.001
      Charlson Comorbidity Index, n (%) 0.024
      1 1,736 (40.0) 437 (37.2) 647 (42.4) 652 (39.9)
      ≥ 2 2,600 (60.0) 738 (62.8) 880 (57.6) 982 (60.1)
      AECOPD hospitalization in the past year, n (%) 1,440 (33.2) 332 (27.4) 517 (33.9) 601 (36.8) < 0.001
      Emergency admission, n (%) 551 (12.7) 130 (11.1) 184 (12.0) 237 (14.5) 0.016
      WBC (109/L), M (IQR) 6.9 (5.5, 8.9) 6.6 (5.4, 8.6) 6.9 (5.6, 9.0) 7.1 (5.6, 9.0) 0.001
      Neutrophils (109/L), M (IQR) 4.7 (3.5, 6.6) 4.5 (3.3, 6.5) 4.7 (3.5, 6.8) 4.9 (3.5, 6.6) 0.007
      Lymphocytes (109/L), M (IQR) 1.3 (0.9, 1.8) 1.3 (0.9, 1.9) 1.3 (0.9, 1.8) 1.3 (0.9, 1.8) 0.793
      Neutrophil ratio,% 69.6 (60.7, 79.0) 69.8 (59.4, 79.3) 69.9 (61.5, 79.0) 69.2 (60.7, 79.0) 0.621
      Eosinophils (/μL), M (IQR) 110 (20, 210) 100 (20, 200) 110 (20, 220) 120 (30, 230) <0.001
      Basophils (/μL), M (IQR) 20 (10, 30) 20 (10, 30) 20 (10, 30) 20 (10, 30) < 0.001
      ESR (mm/h) , M (IQR) 11.0 (4.0, 24.0) 13.0 (4.0, 26.0) 11.0 (3.0, 23.0) 10.0 (3.0, 22.0) < 0.001
      Alb (g/L), M (IQR) 36.4 (33.2, 39.1) 35.8 (32.6, 38.6) 36.4 (33.2, 39.0) 36.8 (33.7, 39.4) < 0.001
      Glb (g/L), M (IQR) 26.8 (23.5, 30.7) 27.8 (24.3, 31.7) 26.9 (23.6, 30.8) 26.0 (22.9, 29.9) < 0.001
      ALT (U/L), M (IQR) 16.0 (12.0, 23.0) 16.0 (12.0, 23.0) 17.0 (12.0, 23.0) 16.0 (12.0, 23.0) 0.209
      AST (U/L), M (IQR) 20.0 (16.0, 25.0) 20.0 (16.0, 26.0) 20.0 (16.0, 26.0) 19.0 (16.0, 25.0) 0.012
      Cr (umol/L), M (IQR) 66.7 (55.9, 80.2) 65.0 (54.7, 80.0) 67.1 (56.1, 80.6) 67.2 (56.4, 79.7) 0.064
      BUN (umol/L), M (IQR) 5.8 (4.7, 7.4) 5.8 (4.6, 7.4) 5.8 (4.6, 7.5) 5.9 (4.7, 7.3) 0.566
      AECOPD, acute exacerbation of chronic obstructive pulmonary disease; WBC, white blood cells; ESR, erythrocyte sedimentation rate; Alb, albumin; Glb, globulin; TBIL, total bilirubin; DBIL, direct bilirubin; IBIL, indirect bilirubin; AST, aspartate aminotransferase; ALT, alanine aminotransferase; Cr, creatinine; BUN, blood urea nitrogen.

      Table 1. 

      Baseline characteristics of AECOPD inpatients by different smoking groups.

    • Total Never smokers Ever smokers
      < 40 pack-years      		 Ever smokers
      ≥ 40 pack-years      		 p
      Antibiotics Antibiotics use, n (%) 4,074 (94.0) 1,083 (92.2) 1,445 (94.6) 1,546 (94.6) 0.011
      Antibiotics course (d), M (IQR) 9 (13, 19) 9 (12, 18) 9 (12, 18) 9 (13, 19) 0.125
      Combination of ≥ 2 antibiotics, n (%) 2,233 (51.5) 578 (49.2) 791 (51.8) 864 (52.9) 0.149
      Corticosteroids Corticosteroids use, n (%) 3,338 (77.0) 852 (72.5) 1,197 (78.4) 1,289 (78.9) < 0.001
      Corticosteroids dose (mg), M (IQR) 200 (120, 280) 200 (94, 320) 187 (120, 280) 187 (120, 280) 0.492
      Corticosteroids course (d), M (IQR) 4 (2, 7) 5 (2, 7) 4 (2, 7) 4 (2, 7) 0.714

      Table 2. 

      Characteristics of in-hospital antibiotics and corticosteroids treatment for AECOPD by smoking groups.

    • Never smokers Ever smokers
      < 40 pack-years      		 Ever smokers
      ≥ 40 pack-years
      Number of cases (%) 1,175 (27.1) 1,527 (35.2) 1,634 (36.7)
      Antibiotics use,
      OR (95% CI)      		 Ref 1.84 (1.32−2.57) 1.80 (1.29−2.53)
      Corticosteroids use,
      OR (95% CI)      		 Ref 1.41 (1.17−1.71) 1.46 (1.20−1.78)
      Note: Logistic model adjusted for age (< 65 years = 0, ≥ 65 years = 1), gender (female = 0, male = 1), Charlson Comorbidity Index (score 1 = 0, score ≥ 2 = 1), emergency admission (no= 0, yes = 1), AECOPD hospitalization in the past year (no = 0, yes = 1), complex infection defined as comorbid pneumonia, bronchiectasis, or use mechanical ventilation (no = 0, yes = 1).

      Table 3. 

      The association of smoking history with antibiotics and corticosteroids use in AECOPD inpatients (OR and 95% CIs).

    • Never smokers Ever smokers
      < 40 pack-years      		 Ever smokers
      ≥ 40 pack-years
      Number of cases 1,175 1,527 1,634
      In-hospital mortality
      N (%) 24 (2.0) 29 (1.9) 22 (1.3)
      Multi-adjusted OR (95% CI) Ref 0.98 (0.54−1.76) 0.68 (0.35−1.34)
      30–day AECOPD readmission
      N (%) 76 (6.5) 107 (7.0) 90 (5.5)
      Multi-adjusted OR (95% CI) Ref 0.99 (0.72−1.38) 0.70 (0.49−1.00)
      90–d AECOPD readmission
      N (%) 130 (11.1) 202 (13.2) 234 (14.3)
      Multi-adjusted OR (95% CI) Ref 1.09 (0.85−1.41) 1.13 (0.87−1.47)
      1–year AECOPD readmission
      N (%) 274 (23.0) 444 (29.1) 535 (32.7)
      Multi-adjusted OR (95% CI) Ref 1.24 (1.02−1.51) 1.43 (1.17−1.76)
      Note: Logistic model adjusted for age (< 65 years = 0, ≥ 65 years = 1), gender (female = 0, male = 1), Charlson Comorbidity Index (score 1 = 0, score ≥ 2 = 1), emergency admission (no = 0, yes = 1), AECOPD hospitalization in the past year (no = 0, yes = 1), complex infection defined as comorbid pneumonia, bronchiectasis, or use mechanical ventilation (no = 0, yes = 1), antibiotics use (no = 0, yes = 1), and corticosteroids use (no = 0, yes = 1).

      Table 4. 

      The association of smoking history with in-hospital mortality and AECOPD readmission risk.