Table 3 Prevalence, sensitivity, specificity and OR of numbers of RF isotypes, alone and in combination with the three most frequent ACPA specificities, anti-CCP2 antibodies and anti-carbamylated protein antibodies in pre-symptomatic individuals and population control subjects

1 RF

123

39

20.6 (17.5–24)

92.1 (89.3–94.2)

3 (2.1–4.4)

2 RF

56

7

9.4 (7.3–12)

98.6 (97–99.4)

7.2 (3.2–15.9)

3 RF

58

1

9.7 (7.6–12.4)

99.8 (98.7–100)

52.7 (7.3–382.2)

≥1 RF

237

47

39.6 (35.8–43.6)

90.4 (87.5–92.7)

6.2 (4.4–8.8)

≥2 RF

114

8

19.1 (16.1–22.4)

98.4 (96.7–99.2)

14.2 (6.9–29.5)

3 RF

58

1

9.7 (7.6–12.4)

99.8 (98.7–100)

52.7 (7.3–382.2)

CCP2 + ≥1 RF

124

3

20.7 (17.7–24.2)

99.4 (98.1–99.9)

42.6 (13.5–135)

CCP2+ ≥2 RF

83

2

13.9 (11.3–16.9)

99.6 (98.4–100)

39.5 (9.7–161.4)

CCP2 + 3 RF

50

1

8.4 (6.4–10.9)

99.8 (98.7–100)

44.8 (6.2–325.5)

CCP2 + ≥1 RF + CarP

35

0

6.1 (4.4–8.4)

100 (99–100)

–

CCP2+ ≥2 RF+ CarP

30

0

5.1 (3.6–7.3)

100 (99–100)

–

CCP2 + 3 RF+ CarP

22

0

3.7 (2.5–5.6)

100 (99–100)

–

CEP-1 + ≥1 RF

96

6

16.3 (13.5–19.5)

98.8 (97.2–99.5)

15.5 (6.7–35.7)

CEP-1+ ≥2 RF

64

3

10.8 (8.6–13.6)

99.4 (98.1–99.9)

19.5 (6.1–62.5)

CEP-1+ 3 RF

38

1

6.4 (4.7–8.7)

99.8 (98.7–100)

33.2 (4.5–243.1)

CEP-1 + ≥1 RF + CarP

28

0

4.9 (3.4–7)

100 (99–100)

–

CEP-1+ ≥2 RF + CarP

25

0

4.3 (2.9–6.3)

100 (99–100)

–

CEP-1+ 3 RF + CarP

17

0

2.9 (1.8–4.7)

100 (99–100)

–

Fibβ_36–52 + ≥1 RF

91

6

15.4 (12.7–18.6)

98.8 (97.2–99.5)

14.5 (6.3–33.5)

Fibβ_36–52 + ≥2 RF

57

2

9.7 (7.5–12.3)

99.6 (98.4–100)

25.8 (6.3–106.1)

Fibβ_36–52 + 3 RF

35

1

5.9 (4.3–8.2)

99.8 (98.7–100)

30.5 (4.2–223.2)

Fibβ_36–52 + ≥1 RF + CarP

23

0

4 (2.7–6)

100 (99–100)

–

Fibβ_36–52 + ≥2 RF + CarP

20

0

3.4 (2.2–5.3)

100 (99–100)

–

Fibβ_36–52 + 3 RF + CarP

14

0

2.4 (1.4–4)

100 (99–100)

–

Filaggrin + ≥1 RF

85

3

14.4 (11.8–17.5)

99.4 (98.1–99.9)

27 (8.5–85.9)

Filaggrin + ≥2 RF

56

2

9.5 (7.4–12.2)

99.6 (98.4–100)

25.3 (6.1–104.1)

Filaggrin + 3 RF

34

1

5.8 (4.1–8)

99.8 (98.7–100)

29.5 (4–216.6)

Filaggrin + ≥1 RF + CarP

23

0

4 (2.7–6)

100 (99–100)

–

Filaggrin + ≥2 RF+ CarP

20

0

3.4 (2.2–5.3)

100 (99–100)

–

Filaggrin + 3 RF + CarP

14

0

2.4 (1.4–4)

100 (99–100)

–

CEP-1 + Fibβ_36–52 + Filaggrin + ≥1 RF

37

1

6.3 (4.6–8.6)

99.8 (98.7–100)

32.3 (4.4–236.4)

CEP-1 + Fibβ_36–52 + Filaggrin + ≥2 RF

28

1

4.7 (3.3–6.8)

99.8 (98.7–100)

24.1 (3.3–177.5)

CEP-1 + Fibβ_36–52 + Filaggrin + 3 RF

20

1

3.4 (2.2–5.2)

99.8 (98.7–100)

16.9 (2.3–126.7)

CEP-1 + Fibβ_36–52 + Filaggrin + ≥1 RF + CarP

13

0

2.2 (1.3–3.8)

100 (99–100)

–

CEP-1 + Fibβ_36–52 + Filaggrin + ≥2 RF + CarP

12

0

2 (1.1–3.6)

100 (99–100)

–

CEP-1 + Fibβ_36–52 + Filaggrin + 3 RF + CarP

10

0

1.7 (0.9–3.2)

100 (99–100)

–