Table 1 Patient demographic and clinical characteristics

Age (year)

60.8 ± 10.5

Proportion of female

83.0%

Disease duration (year)

10.0 (5.0–17.0)

BMI

22.8 ± 3.4

Average dose of prednisolone (mg)

0.0 (0.0–2.0)

CRP (mg/dL)

0.12 (0.03–0.38)

DAS28-CRP

2.39 (1.62–3.47)

SDAI

6.07 (2.35–14.32)

MHAQ

4.0 (0.0–10.0)

Duration of bDMARDs therapy

4.0 (3.0–6.0)

Type of anti-osteoporosis drugs

PTH: 3.5%

Bisphosphonate: 47.1%

Others: 14.4%

None: 35.3%

Change of lumbar spine BMD/12 months (g/cm²)

0.004 (− 0.080 to 0.018)

Percent of least significant reduction of lumber spine BMD

13.1% (20/153)

Change of femoral neck BMD/12 months (g/cm²)

− 0.001 (− 0.025 to 0.019)

Percent of least significant reduction of femoral neck BMD

34.0% (52/153)