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Table 1 Demographic characteristics of matched study cohorts

From: The risk of cancer in patients with rheumatoid arthritis taking tumor necrosis factor antagonists: a nationwide cohort study

Characteristics Biologics nbDMARDs P -value
(n =4,426) (n =17,704)
Age, y, mean (SD) 53.88 (13.08) 53.89 (13.09) 0.97
Female gender, n (%) 3813 (86.20) 15252 (86.20) 1.00
Disease duration before index date, y, median (Q1, Q3) 9.21 (6.84, 11.23) 9.20 (6.81, 11.20) 0.70
Follow-up duration, y, median (Q1, Q3) 3.30 (2.00, 5.39) 3.25 (1.95, 5.29) 0.14
Outcome    
  Cancer, n (%) 89 (2.00) 486 (2.70) 0.001
  Death before outcome, n (%) 192 (4.30) 933 (5.30) <0.001
  Overall observation person-years 16650.63 65587.93  
  Cancer, incidence rates (95% CI) per 1000 person-years 5.35 (4.23, 6.46) 7.41 (6.75, 8.07) <0.005
Number of visits per year during follow ups, median (Q1, Q3) 13.33 (11.61, 14.81) 6.04 (3.15, 9.3) <0.001
Co-morbidities, n (%)    
  Hypertension 1418 (32.0) 5672 (32.0) 1.00
  Chronic liver disease 813 (18.4) 3252 (18.4) 1.00
  Ischemic heart disease 496 (11.2) 1984 (11.2) 1.00
  Diabetes 388 (8.8) 1552 (8.8) 1.00
  Cerebrovascular disease 96 (2.2) 384 (2.2) 1.00
Prior drug use, n (%)1    
  Methotrexate 4125 (93.2) 8659 (48.9) <0.001
  Sulfasalazine 3276 (74.0) 8531 (48.2) <0.001
  Hydroxychloroquine 3515 (79.4) 10976 (62.0) <0.001
  Glucocorticosteroids 4003 (90.4) 12875 (72.7) <0.001
Other systemic drugs use, n (%)2    
  Statin 433 (9.8) 2069 (11.7) <0.001
  Metformin 264 (6.0) 1096 (6.2) 0.60
  NSAID 4349 (98.3) 17041 (96.3) <0.001
  Beta-blockers 1115 (25.2) 4337 (24.5) 0.35
Average dosage of certain DMARDs during follow up, each user, mean (SD)3    
  Methotrexate 9.1(4.32) 6.25 (4.31) <0.001
  Sulfasalazine 822.11(652.64) 720.69 (575.53) <0.001
  Hydroxychloroquine 194.71(137.37) 187.2 (123.95) <0.001
  Glucocorticosteroids 4.42 (3.6) 3.02 (3.21) <0.001
  1. 1Drug users indicate patients using drugs within one year prior to the index date. 2Use of drugs at least once per month on average during follow up. 3The average dosage is depicted as mg/day for all these drugs, except methotrexate (mg/week). DMARDs, disease modifying anti-rheumatic drugs; N, number; NSAID, non-steroidal anti-inflammatory drugs including aspirin and Cox-2 inhibitors; Q, quartile.