Objectives: The objectives of this study were to perform an initial validation of the Gastrointestinal Symptom Scale for Kids (GISSK) in children with juvenile rheumatoid arthritis (JRA); and too evaluate the relationship between gastrointestinal (GI) symptoms and health-related quality of life (HRQOL) in JRA.
Methods: A convenience sample of 77 children (median age, 10 years; range, 2-18 years) with JRA requiring second-line agents and one of their parents were interviewed. GI symptoms during the preceding 1 week were measured using the GISSK, which consists of 2 components, a visual analog scale of GI symptom severity (GISSK-VAS) and an 8-item questionnaire (GISSK-Q; score 0-8; 0= no GI symptoms). Information on medications, joint involvement with arthritis, and a physician rating of disease activity were obtained. Patient-centered outcomes included the Childhood Health Assessment Questionnaire (CHAQ) to assess disability and discomfort. HRQOL was measured by the Pediatric Quality of Life Generic Core Scale (PedsQL-GC) and the Rheumatology Module (PedsQL-RM), as well as a visual analog scale (VAS-health). To determine test-retest reliability, the GISSK was completed by 40 parents twice within a 1- to 2-week period. To determine the quality of parent proxy-reporting, parent ratings were compared with those of their children aged 8 years or older.
Results: GI symptoms were present in the majority of the patients with JRA (58%). Compared with other patients with JRA, those with a GISSK-Q score of > or =2 had significantly lower HRQOL (PedsQL-GC: P < 0.04; PedsQL-RM: P < 0.05; VAS-health: P < 0.02) and more disability (CHAQ: P < 0.002), despite similar disease activity and joint findings. Similar relationships were observed for the GISSK-VAS with traditional outcomes and HRQOL. The test-retest reliability of the GISSK was good (ICCGISSK-Q = 0.60; ICCGISSK-VAS = 0.67). The quality of parent proxy-reporting was fair to good (ICCGISSK-Q = 0.47; ICCGISSK-VAS = 0.66).
Conclusion: GI symptoms are frequent among children with JRA requiring advanced therapies and, if moderate or severe, are associated with significantly lower HRQOL. The GISSK is a reliable and valid measure of GI symptoms and their severity in JRA. This self-administered measure can be used to screen for GI symptoms in clinical practice and may be useful to assess the effects of medication changes on the perceived GI side effects in children with JRA.