Table 3.

Hierarchical multivariate analysis of demographic, medical, and psychological variables in relation to BASDAI. All ß-weights, confidence intervals, and p values for individual variables are estimates in the context of the full model (i.e., with all 3 conceptual blocks entered into the equation). R-square is overall-r-square (%) after the addition of each conceptual block and accompanying p value for the test of the overall R-square. R-square value in last column is the incremental R-square change due to the addition of the conceptual block and accompanying p value for the test of the incremental R-Square change.

Step	Predictors	ß Weights	95% CI	p	R² (%) (p+)	ΔR² (%) (p+)
1	Demographics				13.8 (< 0.001)
	Age	0.15	−0.06 to 0.36	0.157
	Employment	−0.13	−0.26 to 0.01	0.061
	Sex	−0.08	−0.20 to 0.04	0.186
	Marital	0.06	−0.06 to 0.19	0.330
	Education	−0.03	−0.16 to 0.09	0.597
	Smoking	0.02	−0.10 to 0.14	0.748
	Student	−0.03	−0.18 to 0.12	0.737
	Ethnicity	−0.13	−0.25 to −0.01	0.034
2	Medical variables				18.1 (< 0.001)	4.3 (0.814)
	NSAID therapy	0.11	−0.01 to 0.23	0.076
	BASRI	0.01	−0.13 to 0.14	0.901
	Biologic therapy	−0.02	−0.14 to 0.09	0.726
	No. medical comorbidities	−0.08	−0.21 to 0.05	0.203
	CRP	−0.07	−0.19 to 0.05	0.236
	Disease duration	−0.02	−0.21 to 0.17	0.811
3	Psychological variables				51.4 (< 0.001)	33.3 (< 0.001)
	Arthritis internality	−0.19	−0.32 to −0.06	0.005
	Arthritis helplessness	0.16	0.02 to 0.31	0.029
	BRCS	0.08	−0.04 to 0.19	0.203
	Depression (PHQ-9)	0.34	0.19 to 0.49	< 0.0001
	Active coping	0.11	−0.01 to 0.24	0.072
	Passive coping	0.16	0.02 to 0.29	0.027

BASDAI: Bath Ankylosing Spondylitis Disease Activity Index; PHQ: Patient Health Questionnaire; BASRI: Bath Ankylosing Spondylitis Radiographic Index; CRP: C-reactive protein; BRCS: Brief Resilient Coping Scale; PHQ: Patient Health Questionnaire.