Table 2.

Fracture-free survival of patients with and without bDMARD treatment

Covariate	Categories	Fractures/ subjects, n	Person-years, n	Univariate		Multivariate*
			bDMARD	HR (95% CI)	P value	HR (95% CI)	P value
Treatment
	Control	44/1352	17	1.00 (Ref)		1.00 (Ref)
	bDMARD	47/1352	6166	1.05 (0.70 to 1.59)	0.804	1.00 (0.66 to 1.51)	0.999
Gender
	Female	16/973	2050	1.00 (Ref)		1.00 (Ref)
	Male	75/1731	4133	2.54 (1.48 to 4.36)	<0.001	2.40 (1.40 to 4.13)	0.002
CCI score
	Low (1–3)	51/1981	4481	1.00 (Ref)		1.00 (Ref)
	Moderate (4–5)	28/585	1430	1.68 (1.05 to 2.66)	0.028	1.61 (1.02 to 2.56)	0.043
	High (6–7)	7/94	194	2.70 (1.22 to 5.95)	0.014	2.55 (1.16 to 5.63)	0.020
	Very high (≥8)	5/44	78	4.44 (1.77 to 11.12)	0.001	3.91 (1.55 to 9.82)	0.004

Results of univariate and multivariate Cox proportional hazards regression are presented with 95% CI.

*r²=0.009 (likelihood ratio test P<0.001, Wald test P<0.001, score (log-rank) test P<0.001).

bDMARD, biological disease-modifying antirheumatic drugs; CCI, Charlson Comorbidity Index; Ref, reference category.