Table 3 Exposure to methotrexate and/or an anti-TNF biologic in JIA patients and subsequent risk on malignancy development

Total

344

112^Ϯ

2436

11568

Gender

Female

144

43

1087

5096

0.4849

Male

200

69

1349

6472

Mean age (SD)

11.22 (3.23)

10.54 (3.67)

11.55 (3.46)

10.94 (3.65)

<0.0001

Age group (n)

0 – 5

20

12

201

932

0.0054‡

6 – 10

104

38

557

2796

11 – 15

220

62

1678

7840

Follow-up year, mean (SD)

5.93 (2.08)

3.46 (1.82)

6.60 (1.10)

7.78 (0.59)

<0.0001

Duration of drug exposure in year, mean (SD)

2.97 (2.82)

3.05 (1.75)

NA

NA

0.78

Malignancy

Yes

3

1

29

50

<0.0001

No

341

111

2407

11518

Person-years

2030.08

386.73

16114.16

89156.74

Incidence rate ratio (95% CI)

2.64 (0.65-7.53)

4.61 (0.23-23.61)

3.21 (2.01-5.05)

Ref

Relative Risk (95% CI)

2.02 (0.67-6.04)

2.07 (0.36-11.49)

2.75 (1.75-4.32)*

Ref

Population attributable risk (95% CI)

2.85% (-3.53-9.24)

1.01% (-2.82-4.84)

23.38% (10.56-36.21)

Ref

Leukemia

Yes

2

0

8

6

IRR (95% CI)

-

-

7.38 (2.50-22.75)*

Ref

Lymphoma

Yes

0

0

3

2

IRR (95% CI)

-

-

8.30 (1.23-69.79)*

Ref

Soft tissue sarcoma

Yes

0

0

2

1

IRR (95% CI)

-

-

11.07 (0.84-326.4)

Ref

Primary bone cancer

Yes

0

0

1

1

IRR (95% CI)

-

-

5.53 (0.14-215.8)

Ref

Other malignancy

Yes

1

1

15

40

IRR (95% CI)

-

-

2.08 (1.11-3.71)*

Ref