Risk of drug interactions and prescription appropriateness in elderly patients

In Europe, adverse drug reactions and drug interactions are the cause of considerable morbidity and mortality. In over 75s, hospital access due to adverse drug reactions can be as high as 1 in every 3.

To assess the quality of the prescribed polytherapies in the territory, in terms of the risk of drug interactions and of prescription appropriateness, in over 75s.

Randomly selected patients, over 75s, were analysed among the patients of 3 general practitioners. Their data were analysed with the INTERCheck® software. This software provided the list of drug interactions deriving from the chronic therapies. The program also provided the Beers criteria and the STOPP criteria related to the drugs, highlighting potentially inappropriate drugs.

A total of 188 patients were included in the study. A total of 216 serious or very serious drug interactions have been identified. A total of 92 patients (48.9%) were at risk of at least one serious or very serious interaction. The cut-off of the correlation between the number of drugs taken and the risk of incurring a serious or very serious interaction was found to be 5 (AUC = 0.833, sensitivity = 87%, p < 0.001). Patients on ≥ 4 drugs were at risk of prescriptive inappropriateness with a sensitivity of 84% (AUC = 0.781, p < 0.0001).

Focusing on patients with at least 4 drugs in therapy is the right strategy to reduce the risks associated with polypharmacy.