Table 3.

Coefficient signs of the covariates present in the survival submodels fitted with a Cox regression for data sets A, B, C, and D.

Variable		Data set
		A	B	C	D
Sex
	Female (ref)
	Male				–
Year of disease beginning				+
Year of start of the first biologic therapy		+	+
Age at start of the first biologic therapy		–
Disease years until start of the first biologic therapy					–
HLA-B27a				–
Years of education		+	+		+
Baseline CRPb					+
Baseline BASFIc		+	+	+	+

^aHLA-B27: human leukocyte antigen B27.

^bCRP: C-reactive protein.

^cBASFI: disease-modifying antirheumatic drug.