Consequences of screening in abdominal aortic aneurysm: development and dimensionality of a questionnaire

Journal of Patient-Reported Outcomes

Table 2 Fit statistics and reliability (Cronbach’s alpha) of the dimensions of the COS-AAA

Dimensions (Number of items)	CLR-χ²	Degrees of freedom	P	Cronbach’s alpha
Anxiety (7)	21.71	16	0.1528	0.789
Behavioural (7)	24.54	19	0.1761	0.804
Behavioural (6) minus item 9	10.00	16	0,8667	0.804
Sense of dejection (6)	37.24	16	0.0019^d	0.830
Sense of dejection (6)^c	24.24	26	0.5622	0.830
Sleep (4)	51.19	11	< 0.0001^d	0.807
Sleep (3), minus item 23	6.55	8	0.5853	0.840
Uncertainty about the result of the ultra sound examination (3)^b	10.13	7	0.1812	0.343
Change in body perception (8)	21.45	19	0.3124	0.838
Guilt (2)^b	0.00	4	1.0000	0.594
Fear and powerlessness (7)	6.30	19	0.9971	0.849
Negative experiences from the examination (2)	4.93	4	0.2948	0.592
Emotional reactions (3)	2.38	6	0.8820	0.790
Change in lifestyle (2)	0	5	1.0000	0.600
Better not knowing (2)^b	1.22	4	0.8753	0.704
Fear of rupture (4)	7.08	9	0.6286	0.779
Sexuality (3)^b	1.8	8	0.9865	0.820
Information (3)^b	24.77	8	0.0017^d	0.595
Information (2), minus item 65	0	3	1.0000	0.937
Stigmatised (4)^a	5.23	11	0.9193	0.873
Self-blame for smoking (3)^a	5.24	8	0.7312	0.914
Still regretful smoking (6)^a	4.92	5	0.4262	0.890
Existential values (6)	24.66	10	0.0061^d	0.832
Relaxed/calm (3), item 3 possess DIF in relation to diagnosis	3.11	5	0.6831	0.727
Relaxed/calm (2), minus item 3	1.65	3	0.6474	0.716
Social network (3)	8.80	4	0.0662	0.766
Impulsivity (6)	4.83	11	0.9389	0.830
Empathy (3)	6.31	5	0.2776	0.619

^aScales only relevant to former and current smokers
^bOnly for those men diagnosed with screening-detected AAA
^cGraphical log-linear Rasch model where two super items were included: item 1 & item 9 and item 1 & item 15
^dMisfit after a correction by the Benjamini-Hochberg procedure [38]