Table 3.

Multivariable linear regression of the entire cohort on the outcome of femoral neck bone mineral density (g/cm²) (N = 135, r² = 0.32).

Variables	β	95% CI	p-Value
Age	−0.003	−0.005 to −0.001	0.001
Female sex	−0.067	−0.125 to −0.008	0.027
High positive anti-CCPa	−0.049	−0.090 to −0.008	0.019
Disease duration (years)	−0.001	−0.003 to 0.001	0.303
BMIb	0.007	0.003 to 0.010	<0.0001
Frailtyc
Robust	Ref	–	–
Pre-frail	−0.074	−0.129 to −0.020	0.008
Frail	−0.092	−0.177 to −0.006	0.035

All variables included in the multivariate model are shown in table.

CCP: cyclic citrullinated peptide antibody; BMI: body mass index.

^aHigh positive anti-CCP defined as level three times the upper limit of normal (>60 units) based on the 2010 EULAR/ACR RA classification criteria (Aletaha et al., 2010). This threshold was used to minimize heterogeneity of this group.

^bBMI calculated as weight (kg) divided by height (m²).

^cCategories based on Fried Frailty Index (Fried et al., 2001) (score of 0 = robust; 1–2 = pre-frail; 3+ = frail).