There has been considerable attention placed on adverse drug events (ADEs) and their effects on readmission rates worldwide. Several studies have tried to identify the drugs most commonly responsible for ADEs, high-risk patient populations, and the causes of these ADEs. Some of the causes that have been postulated include the aging population, increasing number of drugs on the market, and a troubling upward trend in polypharmacy. The reported rates of ADE-related hospitalizations have varied from study to study. Kongkaew et al. estimated around 5% of all hospital admissions are the result of an adverse drug reaction (ADR), which is a subtype of ADEs. Meanwhile, Shehab et al. estimated approximately 27.3% of emergency department (ED) visits for ADEs result in hospitalization.

Unfortunately, practitioners may exacerbate the problem by prescribing additional pharmacotherapy for conditions caused by an unrecognized ADE. Such circumstances can lead to additional cost and harm to patients. However, pharmacists are uniquely qualified to recognize and address potential ADEs through pharmacist-led medication reconciliation (PLMR). PLMR is the process in which a pharmacist produces an accurate list of medications a patient is taking and compares that list against the patient's documented admission, transfer, and/or discharge orders. Several years of education and training to learn the pharmacokinetic and pharmacokinetic characteristics of a wide variety of medications, as well as any potential side effects, have given pharmacists the skills to detect, assess, and understand ADEs. Many institutions have implemented PLMRs within specific hospital units, such as the ED, in an effort to increase cost savings to the patient and the health care institution.

A meta-analysis of patients with preventable ADEs found that as much as 52% of ADEs, present at the time of hospitalization or an emergency visit, were preventable (8). This highlights the need to produce a tool to predict patients at risk for ADE-related hospitalizations. There have been several ADE risk prediction initiatives developed to identify high risk patients (9-17). Many of these risk prediction tools, such as the Prediction of Hospitalization due to ADRs in Elderly Community-Dwelling Patients (PADR-EC) score and the Brighton Adverse Drug Reactions Risk (BADRI) model, focused on older patients, hospitalized patients, or both. A focus on prediction tools in older adults is reasonable due to ADE-related hospitalization rates among adults 65 years or older, being seven times higher than adults younger than 65 years old (6). However, there is limited information in risk scoring tools for the general public who present to the ED and are at high risk of an ADE. In 2017, a Transitions of Care pharmacy resident at Methodist Dallas Medical Center (MDMC) developed a risk scoring tool to help identify patients in the ED who were at high risk for an ADE-related hospitalization. The scoring tool, which was named the ADE-RED score, took into account the patient's age, presence of polypharmacy, specific high- risk medications, number of previous ED visits, comorbidities, and the reason for their current visit. A score of 12 or more alerted ED pharmacists to perform a PLMR and to make necessary interventions and recommendations to medical staff. Therefore the ADE-RED program has the opportunity to fill a gap in the care for patients who may be hospitalized or return to the ED due to a preventable ADE.

This study will be conducted to determine whether the ADE-RED score can reduce the incidence of ADE- related readmissions compared to the incidence of such readmissions as observed from sister facilities within the Methodist Health System (MHS) and to determine whether the ADE-RED score can predict patients at risk of readmission.