Table 1

Basic characteristics among patients and controls
Cancer patients Controls
Variable Item n % na %a p-value
total 21460 79331
sex
male 12882 60.0 47621 60.0
female 8578 40.0 31710 40.0
age group
18-64 years old 9072 42.3 33536 42.3
65-100 years old 12388 57.7 45795 57.7
income category
not working 6958 32.4 23361 29.4 <.001
monthly income<= NT$20000 11019 51.3 45805 57.7
monthly income> NT$20000 3483 16.2 10165 12.8
comorbidity in 5 years before index date
Myocardial infarction 486 2.3 1784 2.2 0.888
Congestive heart failure 1864 8.7 5917 7.5 <.001
Peripheral vascular disease 609 2.8 2315 2.9 0.534
Cerebrovascular disease 3724 17.4 13514 17.0 0.273
Dementia 655 3.1 2825 3.6 <.001
Chronic pulmonary disease 7002 32.6 25707 32.4 0.534
Rheumatologic disease 692 3.2 2552 3.2 0.957
Peptic ulcer disease 7974 37.2 21875 27.6 <.001
Mild liver disease 4092 19.1 12302 15.5 <.001
Diabetes 4853 22.6 15049 19.0 <.001
Diabetes with chronic complications 1462 6.8 4589 5.8 <.001
Hemiplegia or paraplegia 416 1.9 1609 2.0 0.408
Renal disease 1833 8.5 5734 7.2 <.001
Moderate or severe liver disease 94 0.4 298 0.4 0.191
selective COX-2 inhibitors
No 18872 87.9 69896 88.1 0.504
Yes 2588 12.1 9435 11.9
Average (±sd) DDD 78.0 (±151.1) 85.5 (±231.7) 0.014b
tNSAID
No 2014 9.4 8517 10.7 <.001
Yes 19446 90.6 70814 89.3
Average (±sd) DDD 87.2 (±145.8) 94.5 (±170.0) 0.001b
preferential COX-2 inhibitors
No 15681 73.1 57451 72.4 0.058
Yes 5779 26.9 21880 27.6
Average (±sd) DDD 61.6 (±121.9) 62.2 (144.6) 0.278b

a: weighted according to the matched sizes of cases.

b: Two-sample t-tests were conducted at the natural logarithm of average DDD.

DDD: define daily dose; NT: new taiwan dollar; sd: standard deviation; tNSAID: traditional NSAID.

Yang et al.

Yang et al. BMC Cancer 2012 12:582   doi:10.1186/1471-2407-12-582

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