Table 2 Cancer incidence among dermatomyositis and polymyositis patients by age, gender and years of follow-up

Total

95

18.58

5.11 (5.01 to 5.22)

33

15.36

2.15 (2.08 to 2.22)

Age

   <20 years

1

0.13

7.86 (6.26 to 9.36)

0

0.02

-

   20 to 39 years

8

1.11

7.20 (6.72 to 7.72)

7

0.65

10.69 (9.99 to 11.60)

   40 to 59 years

55

6.67

8.25 (8.03 to 8.47)

13

4.98

2.61 (2.47 to 2.76)

   60 to 79 years

29

5.40

5.37 (5.18 to 5.57)

13

6.80

1.91 (1.81 to 2.02)

   ≥ 80 years

2

0.24

8.47 (7.22 to 9.57)

0

0.52

-

Gender

   Male

39

7.16

5.44 (5.28 to 5.62)

12

6.51

1.84 (1.74 to 1.95)

   Female

56

10.99

5.10 (4.96 to 5.23)

21

8.89

2.36 (2.26 to 2.47)

Follow-up

   <1 years

64

3.00

21.30 (20.81 to 21.86)

18

2.67

6.75 (6.43 to 7.06)

   1 to 2 years

12

2.36

5.08 (4.80 to 5.38)

3

2.30

1.31 (1.16 to 1.46)

   2 to 5 years

13

5.16

2.52 (2.38 to 2.66)

5

4.93

1.01 (0.93 to 1.11)

   >5 years

6

4.39

1.37 (1.26 to 1.48)

7

3.51

1.99 (1.85 to 2.15)