e-STEPS is an observational, non-interventional, retrospective review study of healthcare medical records conducted in PD units at approximately 12 sites in The Netherlands, Germany, Hungary, Portugal, and the UK. There will be no study drug or any other medical intervention involved. Furthermore, no patient-identifying information will be transferred to the Study Coordinating Centre (SCC) or the sponsor. Medical records of cases with e-SP, BP and NoP who meet the proposed study selection criteria will be selected from approximately 12 study sites identified across the 5 European countries.

Each case identified by site study staff as potentially eligible for enrollment into the study will be entered into the case disposition log (CDL) and will be assigned a unique site-specific study identification number. These cases will be considered the study sampling frame. The SCC will select a preliminary target cohort of subjects from the sampling frame by selecting all e-SP cases and undertaking a random sample of NoP and BP cases within site to ensure 1:1:1 enrollment ratio between the 3 study groups. In the event that a sampling frame at a given site contains less NoP or BP cases when compared to e-SP cases, all NoP or BP cases will be selected for enrollment into the study and additional cases will be randomly selected from another site within the country to make up for the deficit if sampling frames allow. Sampling within site or alternatively within country ensures that NoP cases are matched to e-SP cases by lot of recalled PD solution. Cases within The Netherlands, Portugal and the UK all used the same recalled lot of PD solutions. Therefore, if within site and within country sampling cannot be achieved, across country sampling can be undertaken in these 3 countries. If it is determined that all e-SP and NoP cases in the sampling frame were on CAPD at the time of the index event, any BP cases identified in the sampling frame on APD at the time of index event may be excluded from the selection process (may not be selected to comprise the preliminary target cohort) and would therefore not be enrolled into the study.

Local site study staff will review the medical records of the cases included in the preliminary target cohort to confirm eligibility. Those cases meeting the eligibility criteria will comprise the final study cohort and will be enrolled into the study as subjects.

Pseudonymised data from the subjects' medical records will be abstracted by local site study staff and entered at the site into the secured pass-word protected electronic data capture (EDC) system. No patient-identifying information will be available to non-site staff; (i.e., representatives of the SCC and the study sponsor). Over the course of the study, as data are entered, the case status page within the EDC system will automatically update the study disposition of each case. As the data will be automatically quality controlled at the point of data entry into the EDC system on the basis of programmed validation rules for each of the study variables, quality control and query resolution can be managed remotely. Therefore, site data monitoring visits by the SCC are not envisioned. No patient-identifying information will be entered into the EDC system; as such, neither the SCC nor the study sponsor will be able to identify subjects as actual patients.