Clinical Research Directory

Inclusion Criteria: CKD patients will be defined as those meeting any of the following criteria during the observation period: 1. diagnosis of CKD (e.g., "%chronic kidney disease%", "%chronic nephropathy%", "%renal failure%", "%nephritis%" for complete ICD-9/10 code mapping\*) 2. record of hemodialysis (HD) or peritoneal dialysis (PD) (refer to Attachment 2 for dialysis identification algorithms) 3. ≥2 eGFR measurements \<60 mL/min/1.73m² (calculated using CKD-EPI equation) with ≥3-month interval (excluding acute kidney injury) Exclusion Criteria: 1. Non-renal anemia due to trauma, traffic accidents, major hemorrhage, or other confirmed etiologies (e.g., acute hemorrhagic anemia, nutritional deficiency anemia, hemolytic anemia); 2. Diagnosis of acute kidney disease (AKD) without chronic kidney disease (CKD) comorbidity; 3. Incomplete critical data elements (including age, sex, or visit dates).