Gastointestinal-Specific Patient-Reported Outcome Instruments Differentiate Between Renal Transplant Patients With or Without GI Complications

Abstract

Background Gastrointestinal (GI) complications are frequently reported postrenal transplant and are often associated with immunosuppressant regimens including mycophenolate mofetil (MMF). This study evaluated the ability of two GI-specific patient-reported outcome (PRO) instruments to differentiate between patients with and without GI complaints. Methods Discriminant validity of the Gastrointestinal Symptom Rating Scale (GSRS) and Gastrointestinal Quality of Life Index (GIQLI), as well as two generic instruments (Psychological General Well-Being Index (PGWB) and EQ-5D, was assessed in a multinational study of renal transplant recipients. Patients received therapy that included a calcineurin inhibitor and MMF. Both t-tests and ANOVAs were used to examine differences between patients with and without GI complaints, among levels of severity, and between patients reporting presence/absence of specific GI side effects. Results Of 96 patients recruited (56% male), 43% had none, 39% mild, 13% moderate, and 6% severe GI symptoms. All GSRS subscales and the GIQLI total and four of the five subscale scores significantly differentiated between patients with/without GI complications ( P < .05). The PGWB total score and three subscales, the EQ-5D significantly differentiated between the two groups ( P < .05). Only GI-specific instruments discriminated between some severity levels; for example, the GSRS abdominal pain subscale discriminated between patients at all levels of severity ( P < .05). The GIQLI total score and symptoms subscale differentiated between patients with no symptoms and those with mild or moderate or severe symptoms ( P < .05). Conclusions The GSRS and GIQLI differentiated between patients with/without GI side effects and by symptom severity better than did generic instruments, demonstrating excellent discriminant ability in this population.