Data Source

Taiwan launched a single‐payer National Health Insurance (NHI) program on March 1, 1995. The NHI database provides medical information for most of the residents in Taiwan (coverage rate over 98% in 2009), making it one of the largest and most complete population‐based data sets worldwide. The data used in this study came from the Longitudinal Health Insurance Database 2000, a subset of the NHI database containing all claims data from 1996 to 2013 for 1 million beneficiaries randomly selected in 2000. There were no significant differences in age, sex, and healthcare costs between the sample group and all enrollees at that time. The Longitudinal Health Insurance Database 2000 provides encrypted patient identification numbers, sex, date of birth, dates of admission and discharge, the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD‐9‐CM) codes of diagnoses and procedures, details of prescriptions, registry in the Catastrophic Illness Patient Database, and costs covered and paid for by the NHI. The National Health Insurance Research Database has been described in detail in previous studies.18, 19 The accuracy of diagnosis of major diseases in the National Health Insurance Research Database, such as stroke and acute coronary syndrome, has been validated.19 This study was exempt from full review by the institutional review board of Chi‐Mei Hospital (CV code: 10406‐E01).