What is already known about this topic and why is it important?

Patients with end stage renal disease (ESRD) who are on renal replacement therapy (RRT; dialysis or kidney transplantation) have a high risk of death. Analyses of registry data support that survival of RRT patients has increased over the last decades (1,2). However, it is unclear to what extent this better survival can be explained by the overall increase in survival in the general population.

Foster et al. applied time-dependent relative survival models to examine trends over time in the excess risk of death in RRT patients in the USA (3). Excess mortality risk was defined as the mortality risk in the RRT population minus the expected mortality risk in the matched general population. This study has shown that the excess risk of all-cause mortality among RRT patients has significantly decreased between 1995 and 2013 (3).

The results of this study may however not be generalizable to Europe, due to differences in patient case-mix, RRT outcomes and general population life expectancy (4-5). Hence a new study is needed in Europe.

How will you carry out your study?

The ERA-EDTA Registry data will be used to calculate mortality rates for the RRT population, whereas the mortality rates of the general population will be obtained from the WHO database.

We will calculate both the absolute excess RRT-related mortality rate and the relative excess RRT-related mortality risk. The absolute excess of RRT-related mortality rates in each calendar year will be calculated by subtracting the general population mortality rates from the observed mortality rates in the RRT population. To estimate the trend in relative excess of RRT-related mortality risk, time-dependent relative survival models with time-varying covariates will be used. All statistical analyses will be performed using SAS.

How will you decide which patients are included in your study?

Renal registries sending individual patient data to the ERA-EDTA Registry from 2002 onwards will be included in this study. We will include adult patients (=>20 years) who commenced RRT between 2002 and 2015. Patients who indicated that their data shouldn’t be used for research will be excluded.

How many patients do you anticipate including?

We will include about 250.000 ESRD patients starting RRT between 2002 and 2015 from the participating national and regional renal registries in Europe.

For how long will you follow up these patients?

Data will be included from the start of RRT till death occurs or the study ends (31 December 2016).

What new information will your study generate and how will this benefit patients?

To our knowledge this will be the first study to determine the trends in excess RRT-related mortality risk in the European adult population.