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Table 1 Characteristics of the Study Population

From: Post-inhaled corticosteroid pulmonary tuberculosis and pneumonia increases lung cancer in patients with COPD

  ICS
(N = 8813)
No ICS
(N = 35,252)
P-value
Pulmonary infection combinations (%)    <0.001
 None 7823 (88.7) 32,694 (92.7)  
 Pneumonia 703 (8.0) 1654 (4.7)
 TB 182 (2.1) 678 (1.9)
 TB + pneumonia 105 (1.2) 226 (0.7)
Medications (%)
 OCS 3376 (38.3) 1992 (5.7) <0.001
 LABA 4236 (48.1) 1186 (3.4) <0.001
 SABA 7313 (83.0) 6244 (17.7) <0.001
 Theophylline 8305 (94.2) 19,876 (56.4) <0.001
 Statins 1368 (15.5) 5591 (15.7) 0.437
 Aspirin 2652 (30.1) 12,203 (34.6) <0.001
Sex (%)    1.000
 Men 6078 (69.0) 24,312 (69.0)  
 Women 2735 (31.0) 10,940 (31.0)
Age (years, %)    1.000
 20–39 270 (3.1) 1080 (3.1)  
 40–59 1875 (21.3) 7500 (21.3)
 60–79 5328 (60.4) 21,312 (60.4)
80 1340 (15.2) 5360 (15.2)
Comorbidities (%)
 Diabetes 254 (2.9) 1192 (3.4) 0.019
 Hyperlipidemia 1627 (18.5) 7423 (21.1) <0.001
 Chronic kidney disease 1472 (16.7) 7028 (19.9) <0.001
 Smoking-related cancers 124 (1.4) 656 (1.9) 0.004
 Liver cirrhosis 96 (1.1) 423 (1.2) 0.389
 Autoimmune disease 280 (3.2) 1002 (2.8) 0.095
 Atopic dermatitis 162 (1.8) 734 (2.1) 0.147
 Rhinosinusitis 3955 (44.9) 6739 (19.1) <0.001
No. of outpatient visits for respiratory diseases within 2 years after index date (%)a 24.5 ± 14.5 6.0 ± 9.6 <0.001
  ≤ 15 2054 (23.3) 30,735 (87.2) <0.001
  > 15 6759 (76.7) 4517 (12.8)
No. of inpatient visits for respiratory diseases within 2 years after index date (%)a 0.8 ± 1.7 0.2 ± 0.8 <0.001
 0 5779 (65.6) 30,661 (87.0) <0.001
  ≥ 1 3034 (34.4) 4591 (13.0)
Urbanization (%)    <0.001
 High 4934 (56.0) 18,971 (53.8)  
 Mid 2830 (32.1) 11,441 (32.5)
 Low 1049 (11.9) 4840 (13.7)
Death in 2004–2008 (%) 1118 (12.7) 3590 (10.2) <0.001
Follow-up time (person-months) 4.2 × 105 17.4 × 105  
No. of lung cancer 179 496
Incidence rate (per 105 person months) (95 % C.I.) 42.2 (36.5–48.9) 28.5 (26.1–31.1) <0.001
Histologic type (%)    0.148
 Squamous cell carcinoma 34 (19.0) 128 (25.8)  
 Adenocarcinoma 76 (42.5) 173 (34.9)
 Small cell carcinoma 24 (13.4) 57 (11.5)
 Others 45 (25.1) 138 (27.8)
  1. CI confidence interval, HR hazard ratio, ICS inhaled corticosteroid, LABA long-acting inhaled beta-agonist, OCS oral corticosteroid, SABA short-acting beta-agonist, TB pulmonary tuberculosis
  2. aIndex date was defined as the date of initiation of ICS
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