Data collection and evaluation procedures
For all patients aged over 65 years old, demographic information (age and gender), clinical history (diseases and comorbidities) and prescription information were included. Age groups were divided into seven 5-year age groups (66–70, 71–75, 76–80, 81–85, 86–90, 91–95 and ≥96). Patients’ diseases and comorbidities were grouped and identified using a widely accepted diagnosis classification system, the International Statistical Classification of Diseases and Related Health Problems, 10th revision (ICD-10).18Each prescription of an individual patient contained the information of the generic names and brand names, duration and route of administration of each medication, as well as the date of the prescription.