Short summary

Renal transplant patients are at increased risk of developing cardiovascular events compared to the background population. Urinary salt excretion has proven a predictor of cardiovascular events in broader population studies. However, the association has not been well studied among renal transplant recipients and is therefore the aim of this study. Results from this study may impact future guidelines and observation levels of renal transplant patients in Denmark as well as internationally.

Rationale

Kidney transplantation is the optimal treatment for end-stage renal failure in terms of quality of life and overall survival. The transplanted kidney (the kidney graft) is estimated to have a median lifespan of 10-15 years, after which eligible patients need a new transplantation or transition to dialysis. The demand for kidney transplantation is high, with 388 Danes currently on the waiting list, facing an average waiting time of 40 months. This emphasizes the importance of focusing on factors that improve the long-term prognosis for the kidney graft as well as the patients.

While kidney transplant recipients have a reduced risk of cardiovascular diseases compared to dialysis patients, they still face a significantly increased risk compared to the general population. Cardiovascular disease is the leading cause of death among kidney transplant patients, with hypertension being a significant risk factor. Moreover, hypertension is a substantial risk factor for graft kidney function loss.

It is well-known that high salt intake is a modifiable risk factor for hypertension in the general population, but this relationship has not been previously studied among kidney transplant recipients. Currently, guidelines regarding salt intake for kidney transplant patients are extrapolated from data on the general population, but these data may not be directly applicable due to the already increased risk of cardiovascular disease among the kidney transplant recipients.

Therefore, we aim to investigate specific risk factors for cardiovascular disease among kidney transplant recipients, such as salt intake, with the goal of optimizing preventive measures against cardiovascular disease, cardiac death, and early kidney graft rejection.

Description of the cohort

The cohort will consist of patients that have undergone kidney transplantation at Odense University Hospital from 1995 to 2021, identified by ICD10 code DZ940 by journal data extraction.

Data and biological material

The project is conducted as an observational study based on routinely collected clinical and paraclinical journal data (urine samples, blood pressure, etc.) linked with data from national healthcare registries (Central Person Register, National Patient Register, Cause of Death Register, Prescriptions Register).