Association of Dialysis Duration with Outcomes after Transplantation in a Japanese Cohort

Abstract

Background and objectives: Evidence regarding the differences in clinical outcomes after preemptive kidney transplantation (PKT) and non-PKT in Japan is lacking.

Design, setting, participants, & measurements: We conducted a retrospective cohort study at a single center in Japan. Consecutive patients ages >18 years old who had received a kidney transplant from a living donor between November of 2001 and December of 2013 at our institution (n=786) were enrolled. The primary study outcome was the occurrence of clinical events before the end of 2014. Clinical events were defined as any of the following: death with functioning graft (DWFG), graft loss, or post-transplant cardiovascular disease (CVD).

Results: The median follow-up period was 61.0 (35.3-94.0) months. PKT was performed in 239 patients (30.4%). Clinical events occurred in 78 (9.9%). In the Cox proportional hazard model for univariate analysis, factors found to be associated with higher risk of clinical events included older age, men, ABO incompatibility, longer dialysis duration, diabetes, pretransplant CVD, and large ventricular mass index. PKT was associated with lower risk. Clinical event rate in patients who received a PKT was 3.3% compared with 10.8%, 11.1%, 10.4%, 10.2%, 16.7%, and 16.2% among patients who were on dialysis for <1, 1 to <2, 2 to <3, 3 to <4, 4 to <5, and ≥5 years before transplant, respectively (P=0.002). The multivariate analysis showed that ABO incompatibility (hazard ratio [HR], 2.98; 95% confidence interval [95% CI], 1.89 to 4.71), duration of dialysis per year (HR, 1.07; 95% CI, 1.03 to 1.11), and diabetes (HR, 3.54; 95% CI, 2.05 to 6.12) were only three independent risk factors for the incidence of clinical events.

Conclusions: Even in Japan, where the long-term outcomes of patients on hemodialysis are excellent, PKT could be beneficial to reduce DWFG, graft loss, and post-transplant CVD.

Keywords: cohort studies; humans; kidney transplantation; living donor; living donors; proportional hazards models; renal dialysis; risk factors.

Figure 1.

Clinical event–free survival stratified according to kidney transplantation type. (A) shows Kaplan–Meier estimates for preemptive kidney transplantation (PKT) and non-PKT groups. (B) shows Kaplan–Meier estimates in patients with and without ABO blood group compatibility. (C) shows Kaplan–Meier estimates in patients with and without diabetes. (D) shows the results of analysis stratified by age. ABOc, ABO compatible; ABOi, ABO incompatible; DM, diabetes mellitus.

Figure 2.

Clinical event rate according to duration of dialysis. White bar shows a clinical event rate of 9.9% in all patients. Black bars show clinical event rates of 3.3%, 10.8%, 11.1%, 10.4%, 10.2%, 16.7%, and 16.2% in patients according to dialysis durations of 0 (patients with preemptive kidney transplantation [PKT]), <1, 1 to <2, 2 to <3, 3 to <4, 4 to <5, and ≥5 years, respectively. A P value of 0.002 was determined by chi-squared test for the difference between patient groups stratified by dialysis duration.