One of the causes of preventable adverse drug events (EAM) in the older adult population is the inappropriate prescription (PIM), i.e. that prescription where risks outweigh clinical benefits. The aim of this study is to determine the incidence of PIM with Beers criteria and Screening Tool of older person's prescriptions (STOPP), Potentially Prescribing Omissions (PPO) with Screening Tool to alert doctors to Right Treatments (START), and the average costs of hospitalization. This is an incidence study on a sample of patients over 64 years hospitalized, from January to July 2014 at a university hospital. According to Beers criteria, PIM incidence was 61.4%, 65.4% with STOPP and 27.6% PPO with START. The EAM rate calculated was 15.2/100 admissions and 18.6 EAM / 1000 patient days. The OR of EAM with PIM according to Beers and STOPP was 1.49 (IC95% 1.68-4.66) and 1.17 (IC95% 0.62-2.24) respectively. The average cost of hospitalization in patients with EAM were higher than without EAM (p = 0.020). PIM results are in line with most of the studies cited, but slightly higher for Beers and STOPP and lower for START, and the rate of EAM is lower than the data found by Kanaan (18.7% vs. 15.2%). PIM contributes to the appearance of EAM. The costs of hospitalizations with EAM are higher than those without EAM, achieving level of significance.
Keywords: adverse drug events; costs; elderly; hospitalization; inappropriate prescription; omitted prescription.