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 3 Convergent and Discriminant Correlations Between the cTTP-PEQ Domain Scores and Existing PRO Measures

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

	cTTP-PEQ Domain Score
	Fatigue		Activity Limitation		Headache		Pain/Bruising		Cognitive Impairment		Visual Impairment		Mood		Treatment Burden		Total
	Day 1	Day 14	Day 1	Day 14	Day 1	Day 14	Day 1	Day 14	Day 1	Day 14	Day 1	Day 14	Day 1	Day 14	Day 1	Day 14	Day 1	Day 14
PROMIS-29
Average pain rating	0.23	0.35	0.58	0.55	0.51	0.20	0.59^a	0.74^a	0.43	0.42	0.16	0.12	0.37	0.28	0.41	0.38	0.48	0.54
Social Roles/Activities	– 0.60	– 0.62	– 0.47^a	– 0.61^a	– 0.44	– 0.44	– 0.37	– 0.49	– 0.55	– 0.50	– 0.30	– 0.18	– 0.45	– 0.38	– 0.46^a	– 0.42^a	– 0.61	– 0.60
Anxiety/Fear	0.53	0.34	0.62	0.42	0.45	0.56	0.50	0.50	0.64	0.62	0.28	0.28	0.81^a	0.72^a	0.60	0.49	0.72	0.65
Depression/Sadness	0.55	0.55	0.50	0.44	0.31	0.34	0.51	0.44	0.61	0.69	0.36	0.21	0.79^a	0.64^a	0.54	0.52	0.76	0.67
Fatigue	0.86^a	0.79^a	0.56	0.56	0.45	0.36	0.48	0.45	0.43	0.50	0.28	0.22	0.67	0.51	0.67	0.51	0.78	0.68
Pain Interference	0.31	0.41	0.48	0.56	0.58	0.26	0.68^a	0.69^a	0.60	0.53	0.39	0.16	0.53	0.47	0.59	0.38	0.66	0.59
Physical Function	– 0.35	– 0.32	– 0.57	– 0.73	– 0.33	– 0.49	– 0.52	– 0.50	– 0.33	– 0.44	– 0.38	– 0.41	– 0.42	– 0.56	– 0.32	– 0.48	– 0.52	– 0.59
Sleep Disturbance	0.57	0.33	0.38	0.41	0.19	0.43	0.34	0.36	0.19	0.30	0.24	– 0.02	0.24	0.31	0.47	0.41	0.46	0.44
HIT-6 total score	0.62	0.53	0.47	0.47	0.57^a	0.68^a	0.55	0.65	0.31	0.46	0.28	0.20	0.58	0.41	0.71	0.77	0.70	0.71
MCMDM Bleeding Questionnaire Bruising Subscale: total score	0.21	0.21	– 0.05^b	0.09^b	0.29^b	– 0.08^b	0.32^c	0.53^a	0.16^b	0.22^b	0.19	– 0.04	0.17^b	0.18^b	0.36	0.31	0.26	0.38
PDQ-5: total score	0.22	0.40	0.21	0.37	0.41	0.43	0.47	0.57	0.68^a	0.83^a	0.40	0.39	0.58	0.66	0.44	0.57	0.57	0.74
NEI-VFQ-25
General Vision	– 0.19^b	– 0.38^b	– 0.33	– 0.40	– 0.11	– 0.23	– 0.26^b	– 0.35^b	– 0.35	– 0.45	– 0.56^a	– 0.53^a	– 0.41	– 0.54	– 0.31^b	– 0.43^d	– 0.41	– 0.55
Near Vision	– 0.17^b	– 0.25^b	– 0.31	– 0.54	– 0.40	– 0.31	– 0.42^d	– 0.45^d	– 0.35	– 0.35	– 0.18^c	– 0.35^c	– 0.27	– 0.39	– 0.20^b	– 0.22^b	– 0.34	– 0.43
Distant Vision	– 0.28^b	– 0.50^d	– 0.38	– 0.53	– 0.34	– 0.37	– 0.45^d	– 0.42^d	– 0.35	– 0.42	– 0.44^a	– 0.66^a	– 0.43	– 0.41	– 0.19^b	– 0.48^d	– 0.44	– 0.56
WPAI-GH
Work time missed	– 0.04	– 0.31	0.08	– 0.01	0.25	– 0.25	– 0.18	– 0.23	0.03	– 0.25	– 0.15	0.03	– 0.15	0.04	– 0.34	0.31	– 0.22	– 0.20
Impairment while working	0.20	0.23	0.38^c	0.30^c	0.41	0.33	0.12	0.66	0.29	0.46	0.25	0.32	0.03	0.41	0.46^a	0.88^a	0.21	0.73
Overall work impairment	0.16	0.22	0.34	0.35	0.41	0.30	0.06	0.59	0.26	0.40	0.20	0.32	0.01	0.36	0.31	0.90	0.13	0.65
Activity impairment	0.51	0.61	0.63^a	0.51^a	0.41	0.39	0.38	0.48	0.33	0.44	0.27	0.34	0.43	0.48	0.54^a	0.79^a	0.53	0.68
PGI-S	0.47	0.46	0.40	0.63	0.24	0.38	0.47	0.60	0.40	0.45	0.55	0.60	0.50	0.54	0.58	0.65	0.63	0.70

^aConvergent validity confirmed; ^bDiscriminant validity confirmed; ^cConvergent validity not confirmed; ^dDiscriminant validity not confirmed
Correlation coefficient values ≤ 0.19 were considered “very low,” < 0.3 were considered “low,” between 0.3 and 0.49 were considered “moderate,” > 0.5 were considered “high,” and ≥ 0.7 were considered “very high”
Domains are based on a conceptual model because the small sample size did not allow for domains to be constructed using factor analysis
cTTP-PEQ Congenital Thrombotic Thrombocytopenic Purpura–Patient Experience Questionnaire, HIT-6 Headache Impact Test, MCMDM Condensed Molecular and Clinical Markers for the Diagnosis and Management, NEI-VFQ-25 National Eye Institute Visual Function Questionnaire-25, PDQ-5 Perceived Deficits Questionnaire–5 items, PGI-S Patient Global Impression of Severity, PRO Patient-reported outcome, PROMIS-29 Patient-Reported Outcomes Measurement Information System-29 Profile, WPAI-GH Work Productivity and Activity Impairment Questionnaire

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