Higher mortality risk among kidney transplant recipients than among estimated glomerular filtration rate–matched patients with CKD—preliminary results

Abstract Background Although kidney transplantation prolongs survival relative to dialysis, it is associated with a higher death rate than in the general population. The objective of the present study was to assess and compare the risk of mortality and frequency of non-lethal cardiovascular (CV) events in kidney transplant recipients (KTRs) beyond 1 year after successful transplantation versus patients with chronic kidney disease (CKD) using propensity score–matched analysis of estimated glomerular filtration rate (eGFR) and other parameters. Methods After propensity score matching, we studied 340 KTRs from the French Données Informatisées et Validées en Transplantation cohort and 605 non-transplant patients with CKD (CKDps) from the French Chronic Kidney Disease–Renal Epidemiology and Information Network cohort. The mean ± standard deviation eGFR was 42 ± 13 and 41 ± 12 mL/min/ 1.73 m2, respectively (P = 0.649). Descriptive data were completed by a survival analysis with Cox regression models. Results After a median follow-up period of 2.8 years (KTRs 2.0 years, CKDp 2.9 years), 71 deaths were recorded (31 and 40 in the KTR and CKD groups, respectively). Univariate analysis showed that KTRs had a significantly greater risk of mortality than CKDps. In multivariable analysis, KTRs were found to have a 2.7-fold greater risk of mortality [hazard ratio 2.7 (95% confidence interval 1.6–4.7); P = 0.005]. There was no between-group difference concerning the risk of CV events (P = 0.448). CV death rates in KTRs (29.0%) approximated those of CKDps (22.5%), whereas death rates due to infections were higher in KTRs (19.4% versus 10.0%). Conclusion Beyond 1 year after transplantation, KTRs, who possibly had a longer CKD history, had a significantly greater mortality risk than eGFR-matched CKDps. The excess risk was not associated with CV events.