Depression and anxiety in patients with rheumatoid arthritis: prevalence rates based on a comparison of the Depression, Anxiety and Stress Scale (DASS) and the hospital, Anxiety and Depression Scale (HADS)

Table 2 Fit of the DASS-Anxiety and HADS-Anxiety items to the Rasch model

Analysis	Subscale	Item Fit Residual		Person Fit Residual		Chi-Square Interaction			PSI	Uni-dimensionality
		Mean	SD	Mean	SD	Value	DF	P		% tests	CI
Anxiety
1	DASS-A	-0.464	1.385	-0.308	0.945	48.21	28	0.010	0.863	6.63	3.3-9.9
2	DASS-A	-0.371	1.352	-0.272	0.970	36.90	28	0.121	0.860	5.42	2.1-8.7
3	DASS-A	-0.219	0.790	-0.267	1.016	16.48	20	0.686	0.839	1.81	-1.5-5.1
4	HADS-A	-0.026	1.509	-0.296	1.088	23.09	14	0.588	0.838	2.41	-0.1-5.7
Anxiety Combined
5	D+H-A	-0.301	1.418	-0.287	1.067	79.648	42	0.0004	0.892	8.38	5.1-11.7
6	D+H-A	-0.152	1.084	-0.296	1.107	42.17	34	0.158	0.880	9.58	6.3-12.9
7	D+H-A	-0.218	1.019	-0.305	1.046	37.11	32	0.245	0.871	4.79	1.5-8.1
Ideal Fit		0.0	1.0	0.0	1.0			> 0.05*	> 0.7	< 5.0	Lower CI below 5

ISSN: 1471-244X