# Impact of Comorbidities on the Long-Term Survival Rate of Patients Aged 60 Years and Older Undergoing Deceased Donor Kidney Transplantation Versus Continued Waitlisting

## TL;DR

This study finds that kidney transplantation in elderly patients may not improve survival and could be harmful for those with heart disease.

## Contribution

The study identifies a significant interaction between kidney transplantation and cardiovascular disease in determining survival outcomes.

## Key findings

- Kidney transplantation was not significantly associated with overall survival after correcting for immortal time bias.
- Transplant recipients with cardiovascular disease had worse survival compared to dialysis patients.
- A significant interaction between kidney transplantation and cardiovascular disease was found in mortality risk.

## Abstract

Background: The survival benefits of kidney transplantation (KT) versus dialysis in elderly end-stage renal disease (ESRD) patients, particularly those with cardiovascular disease (CVD), remain uncertain. Methods: This retrospective single-center study included 1060 patients aged ≥60 years: 165 KT recipients and 895 dialysis patients. Propensity score matching using five covariates (age, sex, cardiac disease, cerebrovascular accident, and hemodialysis duration) created balanced cohorts of 123 patients per group. Kaplan–Meier analysis and multivariate Cox regression were performed in the matched cohort, and a time-dependent Cox model was additionally applied to the full cohort to address immortal time bias. Results: In the propensity score-matched cohort, KT (HR = 2.72, p = 0.009), age (HR = 1.13, p < 0.001), and CVD morbidity (HR = 3.84, p < 0.001) were independent predictors of mortality. In the time-dependent Cox analysis, KT was not significantly associated with overall survival (HR = 0.94, p = 0.837), but a significant KT × CVD interaction was identified (HR = 3.34, p = 0.025): KT was associated with reduced mortality in patients without CVD (HR = 0.47, p = 0.121) and increased mortality in those with CVD (HR = 1.67, p = 0.174). In patients aged ≥65 years with CVD, KT recipients demonstrated significantly worse survival than dialysis patients (p = 0.004). Conclusions: After correcting for immortal time bias, KT was not significantly associated with overall survival in elderly patients. However, the significant KT × CVD interaction suggests that CVD status is a critical determinant of transplant outcomes.