Failure to replicate the internal structure of Greek-specific thalassemia quality of life instrument in adult thalassemia patients in Sabah

Figures & data

Table 1 Demographic data of the participants (n=82)

	Frequency (%)	Mean (SD)
Age (years)		23.4 (4.2)
Sex
Male	42 (51.2)
Female	40 (48.8)
Iron chelation
Oral pill only	21 (25.6)
Subcutaneous only	3 (3.7)
Combination	58 (70.7)
Level of educationa
No formal education	8 (9.8)
Primary	13 (15.9)
Secondary	49 (59.8)
Tertiary	12 (14.8)
Residence
Inside Kota Kinabalu	21 (25.6)
Outside Kota Kinabalu	61 (74.4)

Note:

a Primary is years 7–12, secondary is years 13–17, tertiary is university program.

Abbreviation: SD, standard deviation.

Table 2 Exploratory factor analysis with varimax rotation for the 40 items

Factor label	Item	Description	EFA
			Component
			1	2	3	4	5	6	7	8	9	10	11	12
ICP impact	q7	I cannot sleep well because of the ICP	0.790
	q29	Iron chelation procedure is painful to me	0.729
	q51	The ICP troubles me	0.727
	q25	The body imprints (eg black spots in the belly from the iron chelation machine or the color on the skin) makes me feel uncomfortable	0.682
	q28	The intake of iron chelation drugs causes me painful abdominal discomforts	0.681
	q8	QoL is affected by the time required by the iron chelation therapy with ICP	0.667
	q6	I lost valuable time to prepare the ICP	0.506
Transfusion impact	q43	The lack of blood units for my transfusion regime affects my emotional status negatively		0.688
	q45	The distance between my home and the thalassemia center creates a problem in my daily life		0.638
	q17	I am treated differently (negatively) in my workplace when they are aware about my disease		0.621
	q44	I experience reactions from the blood transfusion, which affects the general state of my health		0.620
Time spent on treatment and its effect on work and social life	q46	The time that I miss for the transfusion affects my life			0.764
	q47	The time that I miss for the tests affects the quality of my life			0.713
	q20	The disease limits my professional activities (work or school)			0.532
	q19	I cannot go out with my friends as much as I would like to because of the disease			0.494
	q50	I am energetic			0.466
	q16	The time schedule of the intake of ICT affects my social life			0.458
Sex life	q39	My sexual life is affected negatively because of the disease				0.867
	q38	My sexual life is affected negatively because of the iron chelation therapy				0.809
	q36	Splenectomy affects me negatively				0.703
Side effects of treatment	q9	The per os chelation therapy causes me other side-effects					0.769
	q34	I feel somnolence because of the iron chelation					0.654
	q30	I suffer from arthralgias					0.527
Cardiovascular problems	q35	I have arrhythmias because of the disease						0.840
	q32	I have cardiological problems because of the disease						0.607
	q33	I feel fatigue when I have low hemoglobin						0.531
Not interpretable	q31	I have osteoporosis problems because of the disease							0.725
	q23	Some features in my appearance have been changed, a fact that bothers me							0.513
	q15	My social relationships are affected by the ICP							0.447
Psychology	q2	My emotional status restricts my everyday life								0.764
	q48	I feel calm and peaceful								0.723
	q49	I feel hopeless and depressed								0.436
Iron chelation pill impact	q12	The amount of tablets for iron chelation troubles me									0.731
	q14	The way of administration of ICT affects my nutrition									0.709
Not interpretable	q41	Disease complications affect QoL										0.828
	q13	The disease affects my ability to eat or drink whatever I want										0.421
Not interpretable	q42	The origin of the blood (if it is substantially checked) that I will receive causes me anxiety and fear											0.640
	q37	I entered puberty late due to the disease, which affects me negatively											0.533
Not interpretable	q24	I prefer that others not know about my disease												0.742
	q40	I feel tired because of the disease												0.468
		Eigenvalue	9.685	3.231	2.303	2.206	1.948	1.648	1.581	1.519	1.426	1.224	1.085	1.031
		Cumulative %	24.21	32.39	38.05	43.56	48.43	52.55	56.51	60.31	63.87	66.93	69.64	72.22

Abbreviations: EFA, exploratory factor analysis; ICP, iron chelation pump; ICT, iron chelation tablet; QoL, quality of life.

Table 3 Internal structure of the Greek STQOLI

Factor label	Item	Description	EFA
			Component
			1	2	3	4	5	6	7	8	9	10	11
Chelation impact ICP	q51	The ICP troubles me	0.961
	q6	I lose valuable time to prepare the ICP	0.955
	q8	QoL is affected by the time required by the iron chelation therapy with ICP	0.945
	q7	I cannot sleep well because of the ICP	0.926
	q15	My social relationships are affected by the ICP	0.924
Disease effect in mobility and social relations	q41	Disease complications affect QoL		0.732
	q40	I feel tired because of the disease		0.731
	q20	The disease limits my professional activities (work or school)		0.616
	q19	I cannot go out with my friends as much as l would like to because of the disease		0.588
	q30	I suffer from arthralgias		0.544
	q49	I feel hopeless and depressed		0.521
	q31	I have osteoporosis problems because of the disease		0.503
Chelation impact ICT	q12	The amount of tablets for iron chelation troubles me			0.811
	q14	The way of administration of ICT affects my nutrition			0.772
	q9	The per os chelation therapy causes me other side-effects			0.746
	q16	The time schedule of the intake of ICT affects my social life			0.728
Daily activity time	q46	The time that I miss for the transfusion affects my life				0.861
	q47	The time that I miss for the tests affects the quality of my life				0.775
	q45	The distance between my home and the thalassemia center creates a problem in my daily life				0.703
Psychological quality	q50	I am energetic					0.875
	q2	My emotional status restricts my everyday life					0.788
	q48	Feel calm and peaceful					0.747
Effect of chronicity	q35	I have arrhythmias because of the disease						0.709
	q23	Some features in my appearance have been changed, a fact that bothers me						0.617
	q32	I have cardiological problems because of the disease						0.608
	q13	The disease affects my ability to eat or drink whatever I want						0.498
Effect in sexual life	q38	My sexual life is affected negatively because of the iron chelation therapy							0.757
	q39	My sexual life is affected negatively because of the disease							0.740
	q37	I entered puberty late due to the disease, which affects me negatively							0.684
Pain and fatigue	q33	I feel fatigue when I have low hemoglobin								0.752
	q28	The intake of iron chelation drugs causes me painful abdominal discomforts								0.648
	q29	Iron chelation procedure is painful to me								0.513
Transfusion impact	q44	I experience reactions from the blood transfusion, which affects the general state of my health									0.306
	q43	The lack of blood units for my transfusion regime affects my emotional status negatively									0.872
	q42	The origin of the blood (if it is substantially checked) that I will receive causes me anxiety and fear									0.532
Body image	q24	I prefer that others not know about my disease										0.728
	q17	I am treated differently (negatively) in my workplace when they are aware about my disease										0.582
	q25	The body imprints (eg, black spots in the belly from the iron chelation machine or the color on the skin) makes me feel uncomfortable										0.416
	q36	Splenectomy that affects me											0.787
	q34	I feel somnolence because of the iron chelation											−0.529

Note: Copyright ©2012. Dove Medical Press. Adapted from Lyrakos G, Vini D, Aslani H, Drosou-Servou M. Psychometric properties of the specific thalassemia quality of life instrument for adults. Patient Prefer Adherence. 2012;6:477–497.¹¹

Abbreviations: EFA, exploratory factor analysis; ICP, iron chelation pump; ICT, iron chelation tablet; QoL, quality of life; STQOLI, Specific Thalassemia Quality of Life Instrument.

LyrakosGViniDAslaniHDrosou-ServouMPsychometric properties of the specific thalassemia quality of life instrument for adultsPatient Prefer Adherence2012647749722848151

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