Investigation of measurement invariance in longitudinal health-related quality of life in preemptive or previously dialyzed kidney transplant recipients.

PURPOSE: Kidney transplantation (KT) can impact patients' evaluation of health-related quality of life (HRQoL) as they adapt to their new life with a graft and its changes. Patients may adapt to KT in a different way, depending on whether they were on dialysis prior to transplantation or not (i.e. preemptive group). This may result in lack of measurement invariance between these patients' groups and/or over time (i.e. response shift, RS) which may invalidate the between-group comparison of HRQoL change scores. The aim of this study was to investigate and compare RS before and after KT between these two patients' groups. Measurement invariance was investigated between groups and over time with three measurement occasions. METHODS: Adult patients completed the SF-36 at the last visit before KT, and 3, 6 months after. A structural equation model-based procedure was used to (i) detect and take into account measurement non-invariance between groups and RS, if appropriate, (ii) identify the period of occurrence of RS, (iii) study the heterogeneity of RS between the two groups. RESULTS: Before KT (i.e. baseline), measurement invariance was not rejected between dialyzed (n = 196) and preemptive (n = 178) patients' groups. Between baseline and 3 months after KT, similar uniform recalibration was detected on the general health domain in both groups. Uniform recalibration was found between 3- and 6 months after KT on the vitality domain for preemptive patients only. CONCLUSION: HRQoL, adjusted for RS, increased overall for preemptive and dialyzed kidney transplant patients after transplantation. RS may reflect differing adaptation processes following KT.

Comparison of longitudinal quality of life outcomes in preemptive and dialyzed patients on waiting list for kidney transplantation.

PURPOSE: The waiting list period for kidney transplantation can be lengthy and associated with a deteriorated health-related quality of life (HRQoL). It might also be experienced differently depending on the experience of renal replacement therapy (preemptive or dialyzed patients), and the type of dialysis. The main objective of this study is to measure and compare HRQoL changes in preemptive, hemodialysis (HD), and peritoneal dialysis (PD) patients during the waiting list period for kidney transplantation. METHODS: A sample of adult patients on kidney transplant waiting list from three French University Hospital centers was recruited. HRQoL was measured using the SF-36 and a specific questionnaire (ReTransQol), which were collected every 6 months before transplantation in preemptive, HD, and PD patients. Mixed-effects models taking into account time and possible confounding factors were used to compare HRQoL changes between the three groups. RESULTS: Preemptive (n = 230), HD (n = 177), and PD patients (n = 39) were enrolled. The renal replacement therapy modalities, time (time on waiting list and age at registration), and gender were associated with HRQoL changes. The HD and PD patients had a significantly lower perceived HRQoL on Role Physical, Social Functioning, and Role Emotional dimensions than the preemptive patients, with lower scores for PD compared to HD patients. The HRQoL scores of all patients were lower compared to the French general population for all dimensions. CONCLUSIONS: A better understanding of pre-transplantation patients' experience can help improving patient care with adapted educational programs and psychological support depending on the type of renal replacement therapy.