Table 3 Disease and demographic characteristics of patients based on the status of protective antibody levels at 1

Age (years); mean (SD) (range)

51.7 (13) (24-79)

60.1 (11) (30-85)

P < 0.001 ^a

Patient age ≥65 years (%)

16%

37%

P < 0.001 ^b

Gender (female %)

58%

72%

P = 0.01 ^b

Disease duration (years); mean (SD) (range)

13.8 (10) (0-45)

16.7 (11) (0-46)

P = 0.039 ^a

DAS at vaccination; mean (SD) (range)

3.0 (1.3) (0-5.6)

3.5 (1) (0-6.4)

P = 0.001 ^a

HAQ at vaccination; mean (SD) (range)

0.6 (0.5) (0-2)

0.9 (0.7) (0-3)

P < 0.001 ^a

RA (yes, %)

38/62

66/34

P < 0.001 ^b

Ongoing MTX (yes, %)

44%

61%

P < 0.001 ^b

Ongoing anti-TNF treatment (yes, %)

60%

72%

P = 0.029 ^b

Positive antibody response for 6B and 23F at 4 to 6 weeks of follow-up (yes, %)

37.1%

25%

P = 0.027 ^b

Protective antibody levels for both 6B and 23F serotypes at vaccination (%)

72%

20.6%

P < 0.001 ^b