Multi-State Survival Analysis in Renal Transplantation Recipients

BACKGROUND Renal transplantation is a therapy for end-stage renal disease. During the study of recipients' survival after renal transplantation, there are some events as intermediate events that not only affect the recipients' survival but also events which are affected by various factors. The aim of this study was to handle these intermediate events in order to identify factors that affect recipients' survival by using multi-state models. METHODS This retrospective cohort study included 405 renal transplant patients from Afzalipour Hospital, Kerman, Iran, from 2004 to 2010. The survival time of these recipients was determined after transplantation and the effect of various factors on the death hazard with and without renal allograft failure and hazard of renal allograft failure was studied by using multi-state models. RESULTS During 4.06 years (median) of follow-up; 28 (6.9%) recipients died and allograft failure occurred in 51 (12.6%) recipients. Based on the results of multi-state model, receiving a living kidney transplantation decreased the hazard of renal allograft failure (HR=0.38; 95% CI: 0.17- 0.87), pre-transplant hypertension (HR=2.94; 95% CI: 1.54- 5.63) and serum creatinine levels >1.6 upon discharge from the hospital (HR=7.38; 95% CI: 3.87- 7.08) increased the hazard of renal allograft failure. Receiving living kidney transplantation decreased the hazard of death directly (HR=0.18; 95% CI: 0.04- 0.93). CONCLUSION It was concluded that the effect of donor type, pre-transplant hypertension and having serum creatinine >1.6 upon discharge from the hospital was significant on hazard of renal allograft failure. The only variable that had a direct significant effect on hazard of death was donor type.