654 OCTOBER 2016 www.ajmc.com MANAGERIAL D isruptions to, and changes in, a patient’s outpatient medica- tion regimen occur frequently during hospitalization. This often results in discrepancies between drugs prescribed at dis- charge and the medications outpatient providers believe that patients should be on. 1 Although the majority of such discrepancies do not have clinically important efects, their consequences can be profound. These events are defned as preventable adverse drug events (ADEs) because they are caused by medication discrepancies that could have been avoided. It is estimated that 2.4% to 4.1% of all hospital admissions are directly related to ADEs, and up to 69% of those ADEs are preventable. 2-5 There are other circumstances in which the presence of a medication discrepancy has not yet resulted in an ADE, but may still be costly and/ or may expose patients to the risks of additional testing or monitoring. 6 Medication reconciliation by pharmacists at hospital discharge is a possible strategy to reduce medication discrepancies and sub- sequent ADEs. Several systematic reviews have found that medi- cation reconciliation signifcantly reduces the risk of medication discrepancies. 7-9 Despite this, not all studies evaluating the impact of medication reconciliation on health resource utilization (HRU) have found benefcial efects. 10-19 These fndings naturally raise ques- tions about the economic value of this intervention and how the balance between the costs and benefts of the intervention could be optimized by, for example, selectively targeting high-risk patients. Accordingly, we conducted a simulation-based cost-beneft analysis to estimate and compare the economic value of 3 strategies at hospital discharge: a) usual care (no intervention), b) nontar- geted medication reconciliation for all patients, and c) targeted medication reconciliation that uses a screening tool to identify patients at high risk of postdischarge ADEs. METHODS Overall Approach We developed a 2-part discrete-event simulation to prospectively model the sequence of events that occur within the 30 days after Economic Value of Pharmacist-Led Medication Reconciliation for Reducing Medication Errors After Hospital Discharge Mehdi Najafzadeh, PhD; Jeffrey L. Schnipper, MD, MPH; William H. Shrank, MD, MSHS; Steven Kymes, PhD; Troyen A. Brennan, MD, JD, MPH; and Niteesh K. Choudhry, MD, PhD ABSTRACT OBJECTIVES: Medication discrepancies at the time of hospital discharge are common and can harm patients. Medication reconciliation by pharmacists has been shown to prevent such discrepancies and the adverse drug events (ADEs) that can result from them. Our objective was to estimate the economic value of nontargeted and targeted medication reconciliation conducted by pharmacists and pharmacy technicians at hospital discharge versus usual care. STUDY DESIGN: Discrete-event simulation model. METHODS: We developed a discrete-event simulation model to prospectively model the incidence of drug-related events from a hospital payer’s perspective. The model assumptions were based on data published in the peer- reviewed literature. Incidences of medication discrepancies, preventable ADEs, emergency department visits, rehospitalizations, costs, and net benefit were estimated. RESULTS: The expected total cost of preventable ADEs was estimated to be $472 (95% credible interval [CI], $247-$778) per patient with usual care. Under the base-case assumption that medication reconciliation could reduce medication discrepancies by 52%, the cost of preventable ADEs could be reduced to $266 (95% CI, $150-$423), resulting in a net benefit of $206 (95% CI, $73-$373) per patient, after accounting for intervention costs. A medication reconciliation intervention that reduces medication discrepancies by at least 10% could cover the initial cost of intervention. Targeting medication reconciliation to high-risk individuals would achieve a higher net benefit than a nontargeted intervention only if the sensitivity and specificity of a screening tool were at least 90% and 70%, respectively. CONCLUSIONS: Our study suggests that implementing a pharmacist-led medication reconciliation intervention at hospital discharge could be cost saving compared with usual care. Am J Manag Care. 2016;22(10):654-661