The “iatrogenic triad”: polypharmacy, drug–drug interactions, and potentially inappropriate medications in older adults

• Published in: International journal of clinical pharmacy Vol. 39; no. 4; pp. 818 - 825
• Main Authors: Novaes, Priscila Horta, da Cruz, Danielle Teles, Lucchetti, Alessandra Lamas Granero, Leite, Isabel Cristina Gonçalves, Lucchetti, Giancarlo
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-08-2017
• Subjects: Aged; Aged, 80 and over; Brazil - epidemiology; Cross-Sectional Studies; Drug Interactions - physiology; Female; Humans; Iatrogenic Disease - epidemiology; Iatrogenic Disease - prevention & control; Inappropriate Prescribing - prevention & control; Inappropriate Prescribing - trends; Independent Living - trends; Internal Medicine; Male; Medicine; Medicine & Public Health; Pharmacy; Polypharmacy; Potentially Inappropriate Medication List - trends; Research Article; Risk Factors; Surveys and Questionnaires; Brazil; Polypharmacy; Drug interactions; Inappropriate prescribing
• ISSN: 2210-7703; 2210-7711
• DOI: 10.1007/s11096-017-0470-2

Background
The elderly population is often in continuous use of several medications and is more subject to the “iatrogenic triad” of polypharmacy, potentially inappropriate medication use and drug–drug interactions. However, few studies have investigated these three factors concomitantly.
Purpose
To assess the prevalence and inter-relationship of potentially inappropriate medication (PIM) use, polypharmacy and drug–drug interactions in older adults, together with their associated factors.
Setting
city of Juiz de Fora, Brazil.
Methods
a cross-sectional, observational and door-to-door epidemiologic study in community-dwelling older adults was conducted.
Main outcome measure
The primary outcomes were polypharmacy, inappropriate medication use (2012 Beers and 2015 STOPP criteria) and drug–drug interactions. Associated factors were also investigated using bivariate and multivariate analyses.
Results
a total of 368 (92%) older adults were in continuous use of at least one drug. There was a high prevalence of polypharmacy (44.6%), drug–drug interaction (72.3%) and PIMs by Beers (42.1%) and PIMs by STOPP (46.2%). Analysis of the inter-relationship of the criteria (polypharmacy, PIMs STOPP and drug–drug interactions) revealed that 108 (29.3%) of the older adults had all three criteria concomitantly and multivariate analysis showed that frailty and having a caregiver were associated with this “iatrogenic triad”.
Conclusion
A high prevalence of iatrogenic effects from drugs was found in the older adults assessed. One in every three elderly participants of the study had all three iatrogenic criteria concomitantly, highlighting the major public health impact of this problem. The results of this study can serve to inform new preventive and educational strategies for health professionals.