Validation of the psychometrics properties of a French quality of life ă questionnaire among a cohort of renal transplant recipients less than ă one year

Background Renal transplantation is considered as the treatment of ă choice for patients with end-stage renal disease. Health-related quality ă of life (HRQoL) of renal transplant recipients (RTR) is very important ă to assess, especially during the first year after transplantation. To ă provide new evidence about the suitability of HRQoL measures in RTR ă during the first post-transplant year, we explored the internal ă structure, reliability and external validity of a French specific HRQoL ă instrument, the Renal Transplant Quality of life Questionnaire Second ă Version (RTQ V2). ă Methods The data were issued from the French multicenter cohort of renal ă transplant patients followed during 4 years (EPIGREN). The HRQoL of RTR ă was assessed five times (at 1, 3, 6, 9 and 12 months after ă transplantation) with the RTQ V2, a specific instrument consisting of 32 ă items describing five dimensions. Socio-demographic information, ă clinical characteristics and HRQoL (i.e., RTQ V2 and SF-36) were ă collected. For the five times, psychometric properties of the RTQ V2 ă were compared to those reported from the reference population assessed ă in the validation study. ă Results Three hundred and thirty-four patients were enrolled. The ă proportions of well-projected items, item-internal consistency, ă item-discriminant validity, floor and ceiling effects, Cronbach's alpha ă coefficients and item goodness-of-fit statistics were satisfactory for ă each dimension at the five times of the study. The suitability indices ă of construct validity were higher than 90 % for each time ă (minimum-maximum: 90.8-97.4 %). The external validity was less ă satisfactory, with a suitability indices ranged from 46.7 % at M1 to ă 66.7 % at M12. However, the discrepancies with the reference population ă (mainly for the gender) appeared logical considering the scientific ă literature on HRQoL of RTR during the first post-transplant year and may ă not compromise the external validity. ă Conclusion These results support the validity and reliability of the RTQ ă V2 for evaluating HRQoL in RTR during the first post-transplant year, ă and confirm that the RTQ V2 is a useful tool to assess the HRQoL ă precociously after transplant.