Table 4.

Measurement properties of the included instruments

	Internal consistency	Test-retest reliability	Interviews/focus groups	Pilot test	Convergent/divergent	Discriminant validity	Measurement error	Criterion validity	Responsiveness
For paediatrics
IMPACT	0.96	ICC: 0.90	(1) Interview with 82 patients (2) Based on IBDQ (3) Item generation, reduction, and selection procedure	Pilot study, wording of question	Correlation with (1) Current disease activity: −0.54 (2) Colitis symptom score: −0.40 (3) PCDAI: −0.63 (4) Disease activity pattern: −0.43	Higher scores for the patients with quiescent disease (P < 0.005)	Test-retest coefficients were calculated.	Correlation with (1) Piers-Harris Happy domain: 0.61 (2) CHQ-87: 0.67	NA
IMPACT-II	0.57 to 0.86	ICC: 0.67 to 0.91	Based on IMPACT	Pilot studies	NA	Higher scores in the patient with severe, moderate symptoms (P < 0.05)	Test-retest coefficients were calculated.	Correlations with Tacqol (1) Item: 0.44 to 0.63 (2) Domain: 0.46 to 0.72	NA
IMPACT-III	(1) Factor analysis conducted; (2) 0.74 to 0.88	ICC: 0.66 to 0.84	Based on IMPACT	Pilot study (20 patients)	Paper and computer versions were comparable	Lower scores in the patient with severe, moderate symptom (P < 0.05)	Test-retest coefficients were calculated.	Correlations with domain of CHQ-87: 0.47 to 0.72	NA
For adults
IBDQ-32	0.70	ICC: 0.90 to 0.99	(1) Interview with 97 patients (2) The most frequent and important items	NA	Correlated with CDAI (r = −0.67)	Lower scores in patients who required surgery (P < 0.05)	Standard deviations of the score changes were of similar magnitude	Correlation of changes in IBDQ and other measures were similar (P < 0.05)	Sensitivity to change for the improved or deteriorated patients (P < 0.05)
SIBDQ	(1) 0.78 (2) 92% and 90% of the variance in CD and UC were explained	r: 0.65	Based on IBDQ-32	NA	Correlation with (1) SCCAI: −0.42 to −0.85 (2) Seo index: −0.41 to −0.64	Lower scores in the patients with moderate-severe relapse (P < 0.05)	Those with unchanged disease status showed no significant difference.	Correlation with the IBDQ-32 (P < 0.05)	(1) Sensitivity to change (P < 0.05) (2) decreased by −0.93 for the relapsed patients
IBDQ-36	NA	NA	Based on interviewer-administered measure	NA	NA	Lower score for IBD patients than the control (P < 0.05)	NA	NA	NA
IBDQ-9	(1) Rasch analysis conducted; (2) UC: 0.95; CD: 0.91	(1) r: 0.76 for UC, 0.86 for CD (2) ICC: 0.82 for UC, 0.84 for CD	Based on IBDQ-36	Pilot test	(1) Item-total correlation: 0.59 to 0.85 (2) Correlation with clinical indices of activity: UC (r = 0.70) and CD (r = 0.70)	Lower scores in the patients with moderate-severe relapse (P < 0.01)	Scores of the first and second questionnaires correlated significantly	Correlation with IBDQ-36: 0.91	(1) Sensitivity to change (P < 0.01) (2) effect size: UC = −2.67, CD = −5.29
RFIPC	(1) Factor analysis conducted; (2) 0.79 to 0.91	(1) r* (instrument): 0.87 (2) r (item): 0.47 to 0.79	(1) 45-min interview (2) items expressed by IBD patients	Add 3 items using pilot study	Associated with greater disease severity, female gender, and lower educational status.	Worse scores for the patients with lower educational status, greater disease severity, female patients and UC patients (P < 0.05)	Test-retest coefficients were calculated.	Associated with SCL-90 (P < 0.05)	NA
CCQIBD	NA	r: 0.75 to 0.95	(1) Based on other instruments (2) Review of the literature and professional experience	NA	NA	Lower scores for Crohn’s surgical patients (P < 0.05)	NA	Associated with sickness impact profile (P < 0.05)	NA
PIBDQL	NA	NA	Comprehensive definition of the patients’ health	NA	PIBDQL scores had relationship with daily stools and CDAI score (P < 0.05)	(1) Higher scores for the surgical patients (P < 0.05) (2) Lower scores for patients than healthy people (P < 0.05)	NA	NA	NA
CGQL	0.866	NA	Structured interview	NA	NA	Lower scores in the patients with 0 ~ 5 years after surgery (P < 0.05)	NA	Correlation with SF-36: 0.31 to 0.74 (P < 0.05)	Sensitivity to change (P < 0.001)
SHS	NA	r: 0.71 to 0.91	Theoretic model was presented.	NA	Correlation with PGWB: −0.51 to −0.78	Higher scores for the patients in relapse (P < 0.001)	Test-retest coefficients were calculated.	Correlation with (1) IBDQ: −0.41 to −0.78 (2) RFIPC: 0.50 to 0.78	Change in SHS was related with change in disease activity P < 0.05)
EIBDQ	(1) Factor analysis conducted (2) Variance extracted: 63% (3) 0.55 to 0.86	NA	Comprehensive review of the IBD literature	Pilot study	Correlation with CDAI (1) CD: 0.52 (2) UC: 0.30	NA	NA	Correlation with SF-36 (1) CD: 0.48 (2) UC: 0.32	NA
CLIQ	0.91–0.93 Rasch analysis conducted, Unidimensional	Reproducibility: 0.91	Literature review, qualitative interviews	Pilot study	Correlation with (1) NHP: 0.53–0.80 (2) U-FIS: 0.79	The QOL in different disease severity patients were significant	Test-retest coefficients were calculated.	Significant differences in CLIQ scores were observed	NA
CUCQ	0.88	ICC: 0.94	Review the literature, consultation with patients and experts	Pilot study (20 patients)	Correlation with (1) HBI: 0.38 (2) SCCAI: 0.35	NA	Test-retest coefficients were calculated.	Correlations with EQ5D (r = 0.58), SF-12 (0.63 and 0.65)	(1) Sensitivity to change (P < 0.05) (2)Responsiveness ratio: 0.64 (3) standardized response mean: 0.89

*r: correlation coefficients; ICC: intraclass correlation coefficient; NA: not available

CDAI: Crohns disease activity index; CHQ-87: Child Health Questionnaire–Child Form 87; EQ5D: EuroQol 5 dimensions; HBI: Harvey Bradshaw index; NHP: Nottingham Health Profile; PCDAI: paediatric Crohn’s disease activity index; PGWB: psychological general wellbeing; SCCAI: simple clinical colitis activity index; SCL-90: The Symptom Check-List-90; SF-12: The 12-item short-form health survey; SF-36: The 36-item short-form health survey; Tacqol: TNO-AZL Children’s Quality of life questionnaire; U-FIS: Unidimensional Fatigue Impact Scale