Table 2

Characteristics of ever-smokers and never-smokers after propensity score matching

Ever-smokersNever-smokersStandardised difference
N155 593155 593
Index date (days from the origination date)1677.8±634.51675.4±640.60.004
Male gender119 343 (76.7)119 325 (76.7)0.000
Age65.8±13.965.5±15.20.021
Patients in hospitals with <500 beds93 174 (59.9)98 727 (63.5)
Brinkman Index677.6±553.40
Target organ of the elective surgery
 Skin or subcutaneous tissues21 982 (14.1)20 855 (13.4)
 Muscle, bone, limb or trunk24 027 (15.4)24 629 (15.8)
 Nervous system, head or CNS3217 (2.1)3477 (2.2)
 Eyes4941 (3.2)6444 (4.1)
 Ear, nose or throat7006 (4.5)6576 (4.2)
 Face, mouth or neck3344 (2.1)3097 (2.0)
 Chest13 549 (8.7)9673 (6.2)
 Cardiovascular23 719 (15.2)20 189 (13.0)
 Abdomen48 845 (31.4)50 787 (32.6)
 Urological system or adrenal gland11 981 (7.7)11 767 (7.6)
 Genital16 473 (10.6)19 765 (12.7)
Comorbidity
 Heart failure21 118 (13.6)20 308 (13.1)−0.016
 Coronary artery disease25 494 (16.4)25 342 (16.3)−0.003
 Peripheral artery disease11 723 (7.5)9631 (6.2)
 Myocardial infarction4449 (2.9)3808 (2.4)
 Stroke/TIA/SE12 867 (8.3)12 303 (7.9)
 Renal dysfunction10 429 (6.7)10 357 (6.7)−0.002
 Hepatic dysfunction25 439 (16.3)24 293 (15.6)
 Hypertension62 624 (40.2)59 316 (38.1)−0.044
 Diabetes mellitus49 380 (31.7)46 383 (29.8)−0.043
 Cancer83 974 (54.0)84 357 (54.2)0.005
 Infectious disease23 598 (15.2)23 218 (14.9)
 COPD11 332 (7.3)8630 (5.5)−0.072
  • N (per cent) or mean±SD. Standardised difference was calculated only for variables used for the calculation of propensity score.

  • CNS, central nervous system; COPD, chronic obstructive pulmonary disease; SE, systemic embolism; TIA, transient ischaemic attack.