Table 4.

Factors influencing development of SI in patients with RA treated with TCZ or TNFIs ^a

Variable	All patients		MTX users
	HR (95% CI) c	P value c	HR (95% CI) d	P value d
Age by decade	1.34 (0.95 to 1.89)	0.093	1.31 (0.86 to 2.00)	0.210
Female	3.27 (0.77 to 13.98)	0.110	2.20 (0.49 to 9.93)	0.305
Comorbidityb	2.20 (0.95 to 5.11)	0.067	2.49 (0.87 to 7.10)	0.088
PSL ≥5 (mg/day)	2.26 (1.02 to 5.01)	0.046	2.04 (0.77 to 5.44)	0.154
Tocilizumab	2.23 (0.93 to 5.37)	0.074	1.93 (0.72 to 5.17)	0.190

^aCox regression hazard models were performed using the independent variables included in the Table; ^bcomorbidity included pulmonary diseases, diabetes mellitus, liver diseases, and kidney diseases; ^cCox regression analysis was applied in all patients; ^dCox regression analysis was applied in patients who were treated with MTX at baseline. CI: confidence interval; HR: hazard ratio; MTX: methotrexate; PSL: prednisolone; RA: rheumatoid arthritis; SI: serious infection; TCZ: tocilizumab; TNFIs: tumor necrosis factor inhibitors.