Polypharmacy as the risk factor of potentially inappropriate medication and medication regimen complexity index in hospitalised elderly patients

Background: The majority of elderly patients often receive complex therapy or polypharmacy due to physiological changes, which can develop into an adverse drug event. Objective: To analyse the risk factors of potentially Inappropriate Medications (PIMs) and medication regimen complexity in elderly patients. Method: This is an observational study with cohort retrospective methods, carried out at the In-patient Unit of Airlangga University Hospital, Surabaya. The inclusion criteria were patients aged >= 60 years old who were admitted between January to December 2019 for at least three days and received at least one drug. PIMs were monitored with Beers Criteria 2019 and therapy complexity was measured with Medication Regimen Complexity Index (MRCI) during admission, hospitalisation, and discharge. Result: Among 357 patients, 60.8% received at least one PIM on admission. Furthermore, the MRCI score decreased from 22.7 at the time of admission to 11.5 on discharge. Patients who received polypharmacy were two to three times more at risk of having PIMs (p < 0.001). The number of medications correlated with the MRCI scores (Correlation Coefficient= 0.815-0.877, p < 0.001). Conclusion: Polypharmacy is one of the risk factors of PIMs and medication regimen complexity, elderly patients who receive polypharmacy must be closely monitored to prevent adverse drug reactions.