GI-SPECIFIC PATIENT-REPORTED OUTCOME INSTRUMENTS DIFFERENTIATE BETWEEN RENAL TRANSPLANT PATIENTS WITH OR WITHOUT GI COMPLICATIONS

Abstract

P872 Background: Gastrointestinal (GI) complications such as diarrhea, vomiting and dyspepsia associated with immunosuppressant use are frequently reported by patients post-renal transplant. Mycophenolic acid (MPA) has been associated with an increased incidence of GI side effects. Studies also show that GI complications can lead to MPA dose reduction/discontinuation and may affect patient Quality of Life (QoL). The purpose of this study was to assess the discriminant validity of 2 GI-specific and 2 generic patient-reported outcome (PRO) instruments for use in future research on the effect of immunosuppressive regimens. Methods: By cross-sectional study design, the discriminant validity of the Gastrointestinal Symptom Rating Scale (GSRS) and Gastrointestinal Quality of Life Index (GIQLI) was assessed in renal transplant recipients (with or without GI complications) recruited from 5 clinical centers in 4 countries. Patients were required to be receiving therapy which included a calcineurin inhibitor and mycophenolate mofetil. Patients completed the GSRS and GIQLI and two generic instruments, the Psychological General Well-Being Index (PGWB) and EQ-5D. t-tests and ANOVAs were used to examine differences between patients with and without GI complaints, among differing levels of severity, and between patients reporting presence/absence of specific GI side effects. Results: Of 96 patients recruited (mean age: 47.4 ± 12.3 years; male: 56%; mean duration since transplant: 3.6 ± 3.6 years), 41 (42%) had none, 35 (39%) mild, 12 (13%) moderate, and 6 (6%) severe GI symptoms (clinician ratings). Patients with GI complaints had worse scores on all questionnaires than those without GI complaints. All 5 GSRS subscales and the GIQLI total and 5 subscale scores significantly differentiated between patients with and without GI complications (p<0.05). The PGWB total score, self-control, general health, and vitality subscales and the EQ-5D significantly differentiated between the two patient groups (p<0.05). Generic instruments were unable to discriminate between severity level, while disease specific instruments were able to discriminate among some levels, e.g., GSRS abdominal pain subscale discriminated between patients at all levels of severity (p<0.05). Other GSRS subscales discriminated between some but not all severity levels. The GIQLI symptoms subscale was the best discriminator, as it differentiated between patients with no symptoms and those with mild or moderate or severe symptoms–although it did not discriminate among severity levels. The GSRS diarrhea subscale was able to significantly discriminate between patients who reported diarrhea as a side effect and those who did not (p<0.0001). Conclusions: The GSRS and GIQLI differentiated between patients with/without GI side-effects and by symptom severity better than generic instruments, demonstrating excellent discriminant ability in the renal transplant population. They can be used for further research to investigate effects on QoL caused by GI complications due to immunosuppressant therapies.