Development and psychometric properties of a short form of the Illness Denial Questionnaire

Figures & data

Table 1 Characteristics of the samples used in studies 1 and 2

	Study 1			Study 2
Characteristics	Total (201)	Patients (118)	Caregivers (83)	Total (202)	Patients (113)	Caregivers (89)
Sex
Female	112	53	59	117	53	64
Male	89	65	24	85	60	25
Age, mean (SD)	56.14 (12.8)	57.53 (11.28)	54.17 (14.55)	55.93 (13.88)	58.81 (12.90)	52.26 (14.27)
(min–max)	(18–83)	(21–28)	(18–83)	(21–82)	(22–82)	(21–76)
School-education years, mean (SD)	10.58 (3.71)	10.77 (3.88)	10.31 (3.45)	10.99 (4.21)	10.63 (4.14)	11.46 (4.28)
(min–max)	(5–25)	(5–25)	(5–18)	(3–25)	(3–21)	(5–25)
Marital status, n (%)
Married	149 (74.1%)	86 (72.9%)	63 (75.9%)	143 (70.7%)	73 (64.6%)	70 (78.7%)
Divorced	9 (4.5%)	6 (5.1%)	3 (3.6%)	16 (7.9%)	12 (10.6%)	4 (4.5%)
Widowed	10 (4.9%)	7 (5.9%)	3 (3.6%)	11 (5.5%)	10 (8.8%)	1 (1.1%)
Not married	33 (16.4%)	19 (16.1%)	14 (16.9%)	32 (15.8%)	18 (15.9%)	14 (15.7%)
Work status, n (%)
Employed	103 (51.2%)	58 (49.1%)	45 (54.2%)	92 (45.5%)	47 (41.5%)	45 (39.8%)
Unemployed	29 (14.4%)	14 (11.9%)	15 (18.1%)	24 (11.8%)	6 (5.3%)	18 (20.2%)
Retired	69 (34.3%)	46 (39%)	23 (27.7%)	86 (42.5%)	60 (53.1%)	26 (29.2%)
Patient’s illness, n (%)
Cardiac	65 (32.3%)	46 (39%)	19 (22.9%)	58 (28.7%)	40 (35.4%)	18 (20.2%)
Neurological	50 (24.9%)	25 (21.2%)	25 (30.1%)	49 (24.2%)	23 (20.4%)	26 (29.2%)
Oncological	45 (22.4%)	25 (21.2%)	20 (24.1%)	54 (26.7%)	24 (21.2%)	30 (33.7%)
Renal	26 (12.9%)	12 (10.2%)	14 (16.9%)	33 (16.3%)	23 (20.4%)	10 (11.2%)
Respiratory	15 (7.4%)	10 (8.5%)	5 (6%)	8 (3.9%)	3 (2.7%)	5 (5.6%)

Table 2 Factor loadings of the confirmatory factor analysis in Study 1

Denial of negative emotions
Item number	Item	λ	R^2
2.	This disorder/disease has made me more insecure. (R)	0.566	0.320
	Questo disturbo/malattia mi ha reso più insicuro.
6.	I am worried about this disorder/disease. (R)	0.928	0.861
	Sono preoccupato per questo disturbo/malattia.
7.	This disorder/disease frightens me. (R)	0.855	0.731
	Questo disturbo/malattia mi spaventa.
10.	Thinking about this disorder/disease leaves me quite indifferent.	0.641	0.410
	Pensare a questo disturbo/malattia non mi fa “nè caldo nè freddo.”
17.	This disorder/disease makes me feel angry. (R)	0.663	0.440
	Sono arrabbiato a causa di questo disturbo/malattia.
21.	This disorder/disease makes me feel sad. (R)	0.834	0.695
	Sono triste per questo disturbo/malattia.
23.	I am more irritable because of this disorder/disease. (R)	0.509	0.259
	Sono più irritabile per questo disturbo/malattia.
Resistance to change
Item number	Item	λ	R^2
1.	There is no reason to modify my lifestyle on account of this disorder/disease.	0.498	0.248
	Non c’è motivo di modificare abitudini a causa di questo disturbo/malattia.
4.	I am facing everything with serenity.	0.640	0.410
	Sto affrontando tutto con serenità.
5.	I often think about how my life will be from now on. (R)	0.683	0.467
	Penso spesso a come sarà la mia vita da adesso in poi.
11.	Some of my usual habits will have to change. (R)	0.669	0.448
	Alcune mie abitudini dovranno cambiare.
12.	The treatments (medications, exercises, or others) do not in fact change my life.	0.338	0.114
	Le terapie (farmaci, esercizi o altro) non cambiano affatto la mia vita.
13.	This disorder/disease is a heavy trial for me to bear. (R)	0.835	0.697
	Questo disturbo/malattia mi mette a dura prova.
15.	I often think about how things are going to turn out. (R)	0.738	0.544
	Penso a come andranno a finire le cose.
16.	Nothing in my life will change on account of this disorder/disease.	0.527	0.278
	Niente nella mia vita cambierà a causa di questo disturbo/malattia.
22.	I will have to give up some of my usual habits. (R)	0.666	0.444
	Dovrò abbandonare alcune abitudini.

Note: R=item reverse.

Table 3 Selection parameters from Rasch analysis

Denial of negative emotions
Item number	Item	DIF (sex)	DIF (type)	Outfit	Infit	Beta	SF
2.	This disorder/disease has made me more insecure.	–	Yes	3.118	1.157	0.019	✖
6.	I am worried about this disorder/disease.	–	–	−4.512	0.828	1.015	✔
7.	This disorder/disease frightens me.	–	–	−3.649	0.835	−0.01	✔
10.	Thinking about this disorder/disease leaves me quite indifferent.	Yes	–	3.236	1.118	2.059	✖
17.	This disorder/disease makes me feel angry.	-	Yes	0.193	1.022	−0.405	✖
21.	This disorder/disease makes me feel sad.	–	–	−3.122	0.878	0.789	✔
23.	I am more irritable because of this disorder/disease.	–	–	2.964	1.157	−0.314	✔
Resistance to change
Item number	Item	DIF (sex)	DIF (type)	Outfit	Infit	Beta	SF
1.	There is no reason to modify my lifestyle on account of this disorder/disease.	–	–	0.962	0.997	0.428	✖
4.	I am facing everything with serenity.	-	Yes	1.183	1.080	−0.765	✖
5.	I often think about how my life will be from now on.	–	–	0.961	1.008	0.901	✔
11.	Some of my usual habits will have to change.	–	–	0.841	0.916	1.425	✖
12.	The treatments (medications, exercises, or others) do not in fact change my life.	–	–	1.198	1.148	0.646	✔
13.	This disorder/disease is a heavy trial for me to bear.	–	–	0.864	0.925	0.929	✖
15.	I often think about how things are going to turn out.	–	–	1.017	1.049	0.702	✖
16.	Nothing in my life will change on account of this disorder/disease.	–	–	0.861	0.978	1.232	✔
22.	I will have to give up some of my usual habits.	–	–	0.893	0.927	0.702	✔

Notes: DIF = shows if differential item functioning is present; Outfit and Infit = item fit indices; beta = item difficulty or location; SF = Inclusion (✔) or not (✖) in the short-form.

Table 4 Confirmatory factor analysis factor loadings of the Illness Denial Questionnaire-Short Form

Denial of negative emotions
Item Number	Item	λ	R^2
6.	I am worried about this disorder/disease.	0.834	0.696
	Sono preoccupato per questo disturbo/malattia.
7.	This disorder/disease frightens me.	0.785	0.616
	Questo disturbo/malattia mi spaventa.
21.	This disorder/disease makes me feel sad.	0.860	0.740
	Sono triste per questo disturbo/malattia.
23.	I am more irritable because of this disorder/disease.	0.604	0.365
	Sono più irritabile per questo disturbo/malattia.
Resistance to change
Item number	Item	λ	R^2
5.	I often think about how my life will be from now on.	0.667	0.445
	Penso spesso a come sarà la mia vita da adesso in poi.
12.	The treatments (medications, exercises, or others) do not in fact change my life.	0.692	0.478
	Le terapie (farmaci, esercizi o altro) non cambiano affatto la mia vita.
16.	Nothing in my life will change on account of this disorder/disease.	0.684	0.469
	Niente nella mia vita cambierà a causa di questo disturbo/malattia.
22.	I will have to give up some of my usual habits.	0.606	0.367
	Dovrò abbandonare alcune abitudini.

Table 5 Correlations between the Anxiety and Depression Questionnaire-Reduced Form and the Illness Denial Questionnaire-Short Form

	Patients		Caregivers
	Anxiety	Depression	Anxiety	Depression
IDQ-SF	− 0.572***	− 0.482***	− 0.452***	− 0.393***
Denial of negative emotions	− 0.560***	− 0.460***	− 0.476***	− 0.465***
Resistance to change	− 0.401***	− 0.387***	− 0.201*	− 0.173

Notes: *P<0.05; ***P<0.001.

Data availability

The data generated and analyzed in the current study are property of Maugeri Scientific Institutes S.p.A. Restrictions apply to the availability of these data, which were used under license for the current study and so are not publicly available.