Using GI-specific patient outcome measures in renal transplant patients: validation of the GSRS and GIQLI

Gastrointestinal (GI) side-effects occur frequently as a result of immunosuppressant regimens used in renal transplant patients. Little effort has been made to quantify the impact of these side-effects on patients' health-related quality of life and symptom severity.

To assess the psychometric characteristics of two GI-specific outcome instruments (the Gastrointestinal Rating Scale (GSRS) and the Gastrointestinal Quality of Life Index (GIQLI)) for use in post-renal transplant patients.

Cross-sectional study conducted at 5 clinical centers in 4 countries. Patients were required to be on mycophenolate mofetil and a calcineurin inhibitor. Patients completed the GSRS, GIQLI and two generic instruments (the Psychological General Well-Being Index and the EQ-5D) at one timepoint. Reliability, construct and known groups validity were assessed.

In general the GSRS and the GIQLI demonstrated Cronbach's alphas higher than 0.70. The GIQLI was moderately to highly correlated with the PGWB and EQ-5D. Correlations among the GSRS and generic instruments were slightly lower. The GSRS and GIQLI both distinguished between patients with and without GI complaints (all p<0.05).

The GSRS and the GIQLI are appropriate for use in a post-renal transplant population. Scores on both instruments demonstrated significant differences between renal transplant patients with GI complications and without GI complications.