Table 3 Cox multivariate analysis for risk of subsequent hospitalization for infection in rheumatoid arthritis patients

Age (years)

1.00 (0.99–1.02)

0.63

–

–

–

–

Gender; female vs. male

0.86 (0.56–1.42)

0.56

–

–

–

–

Disease duration (years)

1.00 (0.99–1.02)

0.65

1.00 (0.99–1.02)

0.67

–

–

  ≥ 10 years vs. < 10 years

1.03 (0.67–1.62)

0.86

1.03 (0.66–1.62)

0.90

–

–

Stage III or IV vs. I or II

1.05 (0.64–1.72)

0.85

1.05 (0.64–1.72)

0.90

–

–

Class III or IV vs. I or II

1.36 (0.84–2.19)

0.21

1.37 (0.85–2.23)

0.20

–

–

RF positive vs. negative

1.57 (0.72–3.40)

0.26

1.57 (0.72–3.44)

0.26

–

–

ACPA positive vs. negative

1.47 (0.65–3.28)

0.35

1.47 (0.65–3.31)

0.36

–

–

Biologics use vs. no use

0.81 (0.51–1.29)

0.37

0.83 (0.51–1.33)

0.43

–

–

MTX use vs. no use

0.67 (0.42–1.06)

0.09

0.68 (0.42–1.09)

0.11

0.96 (0.57–1.61)

0.88

MTX dose (mg/week)

0.98 (0.92–1.03)

0.38

0.98 (0.92–1.04)

0.44

–

–

Oral steroid, > 5 mg/day vs. ≤5 mg/day

2.45 (1.54–3.89)

< 0.01

2.50 (1.56–4.01)

< 0.01

2.25 (1.37–3.67)

< 0.01

Oral steroid dose (mg/day)

1.05 (1.01–1.08)

0.02

1.04 (1.01–1.09)

0.02

–

–

Other DMARDs use vs. no use

1.40 (0.87–2.26)

0.16

1.38 (0.86–2.23)

0.18

1.13 (0.68–1.88)

0.64

Chronic lung disease

1.44 (0.92–2.24)

0.11

1.42 (0.88–2.29)

0.15

1.26 (0.77–2.06)

0.36

Chronic renal dysfunction (eGFR < 60 ml/min)

1.79 (1.15–2.80)

0.01

1.96 (1.19–3.24)

< 0.01

1.69 (1.01–2.83)

0.04

Diabetes

1.42 (0.89–2.28)

0.14

1.39 (0.86–2.25)

0.18

1.09 (0.66–1.81)

0.73

A history of hospital-acquired infection in the prior biologic therapy

1.38 (0.85–2.25)

0.19

1.37 (0.84–2.23)

0.21

-

-