Prescription data and sample selection
This retrospective study focused on elderly patients who were hospitalized from January 2017 to December 2017 in seventy-six hospitals in China. Elderly patients were defined as patients over 65 years of age before or during their hospitalization.
Prescription data were obtained from Hospital Prescription Analysis Cooperation Project. This project was launched in 1997 by a renowned pharmacist in China named Dakui Li. It allowed for the creation of a database that contains anonymized prescription information from seventy-six hospitals located in six cities in China: Beijing, Tianjin, Shanghai, Hangzhou, Guangzhou, and Chengdu. The participating hospitals must follow the ‘recording guidelines’ that require them to strictly control and monitor their own prescription information and each participating hospital has open access to the prescription information database. So far, there is considerable amount of patient prescription information in the database, allowing us to retrospectively evaluate the inappropriate pharmaceutical treatments.17