Our study found that between one and two out of three older patients has at least one PIP among the treatment prescribed at hospital discharge, depending on the tool used for detection. The high frequency of PIPs suggests the urgent need for interventions to reduce them.

Our results suggest that the strategies used for PIP reduction in co-morbid older patients should focus on the management of polypharmacy. Medication review at hospital discharge is highly recommended for patients taking more than six drugs.

A very high frequency of PIP at discharge was observed. By intervening in five drug groups, about 80 % of PIP might be avoided according to either of the two criteria.