Table 2 Cox multivariate analysis for risk of flares in rheumatoid arthritis patients after hospitalization for infection

Age (years)

0.99 (0.98–1.01)

0.53

–

–

–

–

Gender; female vs. male

0.86 (0.57–1.32)

0.50

–

–

–

–

Disease duration (years)

0.99 (0.97–1.01)

0.27

0.99 (0.97–1.01)

0.35

–

–

  ≥ 10 years vs. < 10 years

1.02 (0.69–1.49)

0.93

1.05 (0.71–1.54)

0.82

–

–

Stage III or IV vs. I or II

1.31 (0.84–2.04)

0.23

1.31 (0.84–2.04)

0.23

–

–

Class III or IV vs. I or II

1.35 (0.90–2.03)

0.15

1.39 (0.92–2.09)

0.12

0.96 (0.62–1.50)

0.87

RF positive vs. negative

0.87 (0.50–1.50)

0.61

0.83 (0.48–1.45)

0.51

–

–

ACPA positive vs. negative

1.04 (0.58–1.87)

0.89

1.03 (0.57–1.85)

0.92

–

–

Discontinuation of biologic therapy

2.52 (1.72–3.71)

< 0.01

2.61 (1.76–3.85)

< 0.01

2.75 (1.81–4.18)

< 0.01

MTX use vs. no use

1.23 (0.84–1.81)

0.29

1.23 (0.82–1.83)

0.31

–

–

MTX dose (mg/week)

1.03 (0.99–1.07)

0.20

1.03 (0.98–1.07)

0.23

–

–

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

1.45 (0.98–2.12)

0.06

1.42 (0.96–2.12)

0.08

1.39 (0.92–2.10)

0.12

Oral steroid dose (mg/day)

1.02 (0.98–1.06)

0.40

1.01 (0.97–1.06)

0.51

–

–

Other DMARDs use vs. non use

1.29 (0.86–1.95)

0.23

1.32 (0.87–2.00)

0.19

1.25 (0.82–1.92)

0.30

Chronic lung disease

0.94 (0.64–1.38)

0.75

0.93 (0.60–1.42)

0.73

–

–

Chronic renal dysfunction (eGFR < 60 ml/min)

0.78 (0.51–1.20)

0.25

0.80 (0.50–1.29)

0.36

–

–

Diabetes

0.55 (0.33–0.88)

0.01

0.53 (0.50–1.19)

0.01

0.43 (0.26–0.71)

< 0.01

A history of hospital-acquired infection under biologic therapy

1.45 (0.96–2.20)

0.08

1.48 (0.97–2.25)

0.07

1.74 (1.14–2.67)

0.01