Abstract

Potential Inappropriate prescribing (PIP), Drug-Drug interactions (DDI) and polypharmacy are major risk factors for adverse drug reactions among older persons. Although these factors in many cases co-exist in prescriptions to older persons, very few studies have evaluated the inter-relationship between these factors concomitantly. This study aimed to evaluate PIP and DDI and to determine the associations between PIP, DDI, and polypharmacy among Nigerian older persons. This study was a retrospective evaluation of medicine utilization among older persons at Olabisi Onabanjo University Teaching Hospital, Nigeria, using a medical chart review. Older persons aged ≥60 years, with chronic diseases that attended the medical outpatient clinics of the hospital between 1^st January and 31^st December 2016 were included. Eligible patients’ records were randomly sampled. Information including patients’ demographics, medical and medication histories and current medications were extracted with a checklist. PIP and DDI were evaluated using the 2015 updated Beers Criteria. Associations were determined using Chi-squared test and a binary logistic regression. A total of 352 participants, mean age 69.03±7.35 years were evaluated. According to the Beers Criteria, PIP and DDI among the participants were (124/352, 35.2%) and (20/352, 5.7%) respectively. Majority of the participants (192/352, 54.5%) received polypharmacy. A few participants (12/352. 3.4%) received prescriptions containing PIP, DDI, and polypharmacy concomitantly. DDI was significantly associated with PIP in a logistic regression (OR=0.18, 95%CI=0.05-0.68, p=0.01) and with polypharmacy in a Chi-squared test (OR=3.55, 95%CI=1.16-10.83, p=0.02). This study concludes that PIP, DDI and polypharmacy are interrelated and should be considered when prescribing to older persons.

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