2.1. Study Design and Data Sources

We conducted a retrospective cohort study using nationwide population-based datasets in Taiwan, with 23 million population, including: (1) inpatient hospitalization discharge data, from which we obtained International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes, dates of admission, and health provider characteristics; (2) a registry of catastrophic illnesses, from which we identified long-term dialysis patients and initiation dates. The two databases were linked using encrypted patient identifiers and all data analysis was completed in 2017–2018. This study was approved by the Institutional Review Board at Kaohsiung Medical University Hospital in Taiwan (KMUHIRB-EXEMPT(II)-20150081). All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the Helsinki declaration and its later amendments or comparable ethical standards.