OBJECTIVE: To evaluate the potentially inappropriate medications（PIM） in elderly inpatients in the Aerospace Center Hospital

and probe into the work pattern of PIM pharmaceutical intervention conducted by clinical pharmacists

so as to provide theoretical and practical basis for ensuring rational medication in elder patients. METHODS: Through a single center cohort study

the elder patients hospitalized in the Aerospace Center Hospital from Jan. to Jun. 2021 were selected as research objects. These patients were divided into intervention group and control group based on whether the clinical pharmacists carried out pharmaceutical intervention. The Criteria of Potentially Inappropriate Medications for Older Adults in China（2017 version）（hereinafter referred to as the Criteria） was applied to evaluate the PIM of both groups and analyze the effect of PIM improvements by clinical pharmacists. RESULTS: A total of 455 patients who met the inclusion and exclusion criteria were enrolled in the research

including 214 patients in the intervention group and 241 patients in the control group. To eliminate the effect of confounding factors between two groups

propensity score was used to balance the between-group differences. After matching

there were 164 cases in the intervention group and 164 cases in the control group

a total of 328 patients. By applying the Criteria

257 patients（78.35%） had at least 1 PIM

with 1（1 to 2） PIM per capita. In terms of effectiveness

the incidence of PIM（P=0.023）

PIM per capita（P=0.024） and 90 d all-cause readmission rate（P=0.032） were significantly lower in the intervention group compared with the control group

with statistically significant differences; in terms of economy

the average treatment cost of patients in the intervention group was significantly lower compared with the control group

with statistically significant difference（P=0.022）. CONCLUSIONS: Pharmaceutical intervention on elderly inpatients by clinical pharmacists can not only reduce the incidence of PIM

per capita PIM and 90 d all-cause readmission rate

but also reduce the treatment cost of patients and improves the rationality of clinical medication in elderly patients.