Ascertainment of Diseases and Comorbidities

Our study retrieved data from NHIRD, using ICD-9-CM and ICD-10 disease coding with diagnoses defined as discharge diagnosis or at least two consecutive clinic visits. The accuracy of the diagnosis of has been confirmed and validated in previous studies ^15-17. In addition, Catastrophic Illnesses Registry, which all confirmed cancer patients are required to be registered, enhances the accuracy and completeness of data retrieval of patients with malignancy. The positive predictive value (PPV) of all cancers are 93.64% and the selected cancers are: cervical cancer, PPV 81.73%; colorectal cancer, 94.38%; esophageal cancer, PPV 94.45%; female breast cancer, PPV 91.86%; gastric cancer 91.84%; liver and intrahepatic ducts cancer, PPV 93.03%; lung cancer, PPV 94.90%; oral cavity, oropharyngeal, and hypopharyngeal cancer, PPV 94.40%; prostate cancer, 93.29%; pancreatic cancer, PPV 90.39% ¹⁶. In addition, the PPV of selected comorbidities are: diabetes, PPV 92%; hypertension, PPV 88.5%; hyperlipidemia, PPV 89.5%; heart failure, PPV 97.6%; myocardial infarction, PPV 92.0%; ischemic stroke, PPV 97.9% ¹⁷.