Psychometric evaluation of a patient-reported outcomes instrument for congenital thrombotic thrombocytopenic purpura

Oladapo, Abiola; Ito, Diane; Rodriguez, Ana María; Philpott, Stephanie; Krupnick, Robert; Allen, Veleka; Hibbard, Christopher; Scully, Marie; Ewenstein, Bruce

doi:10.1186/s41687-023-00592-w

Journal of Patient-Reported Outcomes

Table 2 Descriptive Statistics for the cTTP-PEQ Items, Domain Score, and Total Score

From: Psychometric evaluation of a patient-reported outcomes instrument for congenital thrombotic thrombocytopenic purpura

cTTP-PEQ Item (Score Range) or Domain	N = 36						Change from Baseline (SD)^b
	Baseline			Day 14
	Missing, n	Mean (SD) or n (%)^a	Range	Missing, n	Mean (SD) or n (%)^a	Range
Item 1. Fatigue (0–10)	1	4.37 (3.04)	0–10	5	3.55 (2.71)	0–9	– 0.87 (2.49)
Item 2. Joint pain (0–10)	1	2.14 (2.42)	0–8	4	2.19 (2.33)	0–7	0.09 (1.67)
Item 3. Muscle pain (0–10)	1	1.71 (2.49)	0–10	4	1.78 (2.39)	0–8	– 0.03 (1.53)
Item 4. Abdominal pain (0–10)	1	1.63 (2.84)	0–9	4	1.63 (2.71)	0–10	– 0.09 (1.65)
Item 5. Chest pain (0–10)	1	0.60 (1.54)	0–6	4	0.53 (1.32)	0–5	– 0.13 (1.79)
Item 6. Forgetfulness	1			4			0.00 (0.72)
None of the time		8 (22.9)			9 (28.1)
A little of the time		10 (28.6)			9 (28.1)
Some of the time		9 (25.7)			5 (15.6)
A good bit of the time		8 (22.9)			7 (21.9)
Most of the time		0			2 (6.3)
All of the time		0			0
Item 7. Confusion	1			4			– 0.13 (0.49)
None of the time		20 (57.1)			19 (59.4)
A little of the time		6 (17.1)			7 (21.9)
Some of the time		5 (14.3)			3 (9.4)
A good bit of the time		4 (11.4)			3 (9.4)
Most of the time		0			0
All of the time		0			0
Item 8. Difficulty communicating	1			4			– 0.25 (0.76)
None of the time		11 (31.4)			12 (37.5)
A little of the time		11 (31.4)			11 (34.4)
Some of the time		6 (17.1)			5 (15.6)
A good bit of the time		6 (17.1)			3 (9.4)
Most of the time		0			1 (3.1)
All of the time		1 (2.9)			0
Item 9. Blurry vision	1			4			– 0.03 (0.93)
None of the time		18 (51.4)			18 (56.3)
A little of the time		12 (34.3)			7 (21.9)
Some of the time		1 (2.9)			3 (9.4)
A good bit of the time		1 (2.9)			2 (6.3)
Most of the time		2 (5.7)			1 (3.1)
All of the time		1 (2.9)			1 (3.1)
Item 10. Experiencing blind spots	1			4			0.13 (0.55)
None of the time		23 (65.7)			23 (71.9)
A little of the time		7 (20.0)			6 (18.8)
Some of the time		2 (5.7)			0
A good bit of the time		1 (2.9)			1 (3.1)
Most of the time		0			0
All of the time		2 (5.7)			2 (6.3)
Item 11. Headache	1			4			– 0.03 (0.70)
None of the time		12 (34.3)			12 (37.5)
A little of the time		12 (34.3)			9 (28.1)
Some of the time		6 (17.1)			6 (18.8)
A good bit of the time		1 (2.9)			3 (9.4)
Most of the time		3 (8.6)			1 (3.1)
All of the time		1 (2.9)			1 (3.1)
Item 12. Bruising (0–10)	1	1.49 (2.22)	0–9	4	1.63 (2.41)	0–8	0.09 (1.28)
Item 13. Feeling depressed	2			4			– 0.13 (0.89)
None of the time		16 (47.1)			12 (37.5)
A little of the time		8 (23.5)			14 (43.8)
Some of the time		6 (17.6)			2 (6.3)
A good bit of the time		2 (5.9)			2 (6.3)
Most of the time		2 (5.9)			1 (3.1)
All of the time		0			1 (3.1)
Item 14. Anger	1			5			– 0.03 (1.05)
None of the time		12 (34.3)			13 (41.9)
A little of the time		13 (37.1)			11 (35.5)
Some of the time		9 (25.7)			3 (9.7)
A good bit of the time		1 (2.9)			3 (9.7)
Most of the time		0			1 (3.2)
All of the time		0			0
Item 15. Irritable	1			5			0.03 (0.91)
None of the time		5 (14.3)			5 (16.1)
A little of the time		15 (42.9)			15 (48.4)
Some of the time		10 (28.6)			5 (16.1)
A good bit of the time		5 (14.3)			5 (16.1)
Most of the time		0			1 (3.2)
All of the time		0			0
Item 16. Frustrated	2			4			0.16 (1.05)
None of the time		9 (26.5)			8 (25.0)
A little of the time		12 (35.3)			11 (34.4)
Some of the time		8 (23.5)			5 (15.6)
A good bit of the time		4 (11.8)			7 (21.9)
Most of the time		0			0
All of the time		1 (2.9)			1 (3.1)
Item 17. Anxiety	1			4			– 0.50 (0.916)
None of the time		12 (34.3)			13 (40.6)
A little of the time		5 (14.3)			8 (25.0)
Some of the time		7 (20.0)			6 (18.8)
A good bit of the time		7 (20.0)			4 (12.5)
Most of the time		4 (11.4)			1 (3.1)
All of the time		0			0
Item 18. Mood swings	1			4			– 0.13 (1.01)
None of the time		13 (37.1)			16 (50.0)
A little of the time		12 (34.3)			8 (25.0)
Some of the time		5 (14.3)			3 (9.4)
A good bit of the time		4 (11.4)			4 (12.5)
Most of the time		1 (2.9)			0
All of the time		0			1 (3.1)
Item 19. Activity limitation	3			13			– 0.13 (0.78)
Not at all		16 (48.5)			14 (60.9)
A little bit		11 (33.3)			4 (17.4)
Moderately		2 (6.1)			2 (8.7)
Quite a bit		4 (12.1)			3 (13.0)
Extremely		0			0
Item 20. TTP treatment	2			5			NC
No		7 (20.6)			8 (25.8)
Yes		27 (79.4)			23 (74.2)
Item 21. Treatment worry	10			13			0.09 (0.53)
Not at all		18 (69.2)			14 (60.9)
A little bit		3 (11.5)			4 (17.4)
Moderately		1 (3.8)			2 (8.7)
Quite a bit		3 (11.5)			3 (13.0)
Extremely		1 (3.8)			0
Item 22. Allergic reaction to treatment (0–10)	9	0.78 (1.60)	0–5	13	0.43 (1.20)	0–5	– 0.13 (1.58)
Item 23. Drowsiness due to treatment (0–10)	9	3.26 (3.30)	0–8	13	2.74 (2.97)	0–8	– 0.26 (1.63)
Item 24. Treatment pain (0–10)	9	1.85 (2.46)	0–9	13	2.00 (2.71)	0–20	0.17 (1.37)
Item 25a. Work/school missed for treatment-related reason?	1			4			NC
No		23 (65.7)			20 (62.5)
Yes		12 (34.3)			12 (37.5)
Item 25b. Work outside of the home/attend school?	1			4			NC
No		24 (68.6)			25 (78.1)
Yes		11 (31.4)			7 (21.9)
Item 25c. Hours of work/school missed in past 2 weeks	9	1.78 (3.25)	0–12	13	1.61 (2.71)	0–8	– 0.30 (2.55)
Item 26. Travel burden	9			13			0.00 (0.85)
Not at all		12 (44.4)			9 (39.1)
A little bit		6 (22.2)			6 (26.1)
Moderately		4 (14.8)			6 (26.1)
Quite a bit		3 (11.1)			1 (4.3)
Extremely		2 (7.4)			1 (4.3)
Domain score
Fatigue (Item 1)	1	4.37 (3.04)	0–10	5	3.55 (2.71)	0–9	– 0.87 (2.49)
Headache (Item 11)	1	1.26 (1.36)	0–5	4	1.22 (1.31)	0–5	– 0.03 (0.70)
Activity Limitation (Item 19)	3	0.82 (1.01)	0–3	4	0.75 (1.16)	0–4	– 0.13 (0.78)
Pain/Bruising (Items 2, 3, 4, 5, and 12; score range 0–45)	1	8.83 (8.81)	0–34	4	8.97 (8.99)	0–34	– 0.09 (4.06)
Cognitive Impairment (Items 6, 7, and 8; score range 0–15)	1	3.60 (2.80)	0–11	4	3.25 (3.05)	0–11	– 0.38 (1.19)
Visual Impairment (Items 9 and 10; score range 0–10)	1	1.54 (2.50)	0–10	4	1.47 (2.41)	0–10	– 0.16 (1.20)
Mood (Items 13, 14, 15, 16, 17, and 18; score range 0–30)	1	7.46 (5.19)	0–16	4	7.00 (5.96)	0–24	– 0.52 (4.08)
Treatment Burden (Items 21, 22, 23, 24, and 26; score range 0–38)	9	7.81 (7.08)	0–25	13	7.00 (6.35)	0–25	– 0.17 (3.23)
Total score (0–152)	1	33.94 (24.56)	0–99.4		30.95 (23.45)	2.3–92.0	– 3.15 (8.68)

^aMean (SD) and range are presented for numerical variables. Frequency of responses (n, [%]) are presented for categorical variables
^bTo quantify change from baseline, the categorical response options were given a numerical score ranging from 0 to 6
Domains are based on a conceptual model because the small sample size did not allow for domains to be constructed using factor analysis
cTTP Congenital thrombotic thrombocytopenic purpura, cTTP-PEQ Congenital Thrombotic Thrombocytopenic Purpura–Patient Experience Questionnaire, NC Not calculated, PRO Patient-reported outcome, SD Standard deviation, TTP Thrombotic thrombocytopenic purpura

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