Expected and actual adverse drug-drug interactions in elderly patients accessing the emergency department: data from the ANCESTRAL-ED study

ABSTRACT

Objective: This study was aimed at evaluating the frequency and describing the adverse drug-drug interactions (DDIs) recorded among elderly patients accessing the emergency department (ED).

Methods: Patients aged ≥65 years, accessing the ED of Pisa University Hospital (Italy) from 1 January 2015 to 31 December 2015 within the ANCESTRAL-ED program, were included in this study. ‘Expected’ DDIs were assessed using Thomson Micromedex®. Each ED admission (discharge diagnosis) consistent with the signs and symptoms of an expected DDI for each patient was classified as an ‘actual’ DDI.

Results: Throughout the study period, 3473 patients (3812 ED admissions, 58% females, mean age: 80.3) were recorded. The total number of expected DDIs was 12,578 (67 contraindicated; 3334 major; 8878 moderate; 299 minor) detected in 2147 (62%) patients. Overall 464 expected DDIs were found to be consistent with the ED admission in 194 patients (representing 9% of patients with expected DDIs).

Conclusions: More than one half of elderly patients admitted to ED presented at least one expected DDI at the time of ED presentation. However, 9% of the expected DDIs were identified as actual DDIs, based on the consistency of the expected event with the ED discharge diagnosis.

KEYWORDS:

• Elderly patients
• emergency department
• drug-drug interactions
• adverse drug reactions

Acknowledgements

The manuscript has not been previously published in full or simultaneously submitted for publication. However, preliminary results have been presented at the 13th Annual Meeting of ISoP as poster and the abstract published on the abstract book (A. Capogrosso-Sansone, C. Blandizzi, S. Montagnani, E. Ruggiero, S. Mantarro, A. Saporiti, S. Felici, A. Marino, G. Pasqualetti, F. Monzani, M. Santini, M. Tuccori. Drug-drug interactions in elderly patients: a 1-year prospective survey in an emergency department; Drug safety.2013:36:913-914) and at the 15th Annual Meeting of International Society of Pharmacovigilance (ISoP) as poster and the abstract published on the abstract book (A. Marino, A. Capogrosso-Sansone, C. Blandizzi, S. Mantarro, I. Convertino, S. Montagnani, A. Saporiti,G. Bini, R. Sieli, G. Pasqualetti, F. Monzani, M. Santini, M. Tuccori. Potential and actual drug-drug interactions in elderly patients admitted to an emergency department: data from the ANCESTRAL-ED study. Drug safety.2015:38:1000-1001).

Declaration of interest

The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Additional information

Funding

The study was funded by the Tuscan Region Authority with a grant for drug safety active surveillance programs issued by the Italian Drug Agency (Agenzia Italiana del Farmaco, AIFA). This paper is part of a supplemental issue funded by the Second University of Naples.