The purpose of this study was to verify the parent-proxy IMPACT-III (IMPACT-III-P) in a group of adolescents with inflammatory bowel disease (IBD). Parent-proxy report measures are used in paediatric psychosocial evaluation, and the IMPACT-III-P will give a more comprehensive picture of HRQOL. Analyses of reliability and validity were out. Parents of children aged 8 to 17 with IBD reported on their child’s HRQOL and depression (BASC-2); children reported on their HRQOL, pain interference (PROMIS Pain Interference), and illness symptoms; and clinicians completed disease activity assessments. The IMPACT-III-P was highly, favourably linked with the PedsQL, establishing criterion validity. Higher IMPACT-III-P scores were linked with reduced pain interference and lower depression, indicating convergent validity. Higher IMPACT-III-P scores were linked with reduced child-reported symptoms, but scores did not change according to inactive, mild, or moderate/severe disease activity groups as evaluated by clinicians. Internal consistency, parent-child agreement, and item-level studies all indicated a high level of dependability. 

The IMPACT-III-P was shown to have high validity and reliability. HRQOL was reported similarly by parents and children, with parents ranking child HRQOL somewhat lower. The findings suggest the use of the IMPACT-III-P for youth aged 8 to 17 in conjunction with the child IMPACT-III to offer useful information on HRQOL in youth with IBD.