An Exploratory Comparison of Medication Lists at Hospital Admission with Administrative Database Records

BACKGROUND: Medication reconciliation is recognized as important, but no one method has been recommended. Research has shown that the most common medication reconciliation errors are attributable to omitted medications and doses. The pharmacy claims aggregator used in this evaluation is a private company that gathers pharmacy claims data from disparate pharmacy benefit managers into a secure repository (hereafter referred to as the claims database) under contracts with public and private health plans. A web interface for the repository can be used by subscribing health systems and health care providers to view patient-level pharmacy claims data to support patient care. At the time of this study, the claims database contained information from 5 public and private health insurance programs covering approximately 500,000 enrollees in Arizona. OBJECTIVES: To compare current medication lists (medication name and strength) collected by patient interview upon admission at a medical center with those collected by a company that aggregates pharmacy claims data. METHODS: This study was a retrospective chart review. A list of 300 patients was produced by a medical center using random number generation for patients who were (a) admitted to the medical center from January 1, 2007, through June 30, 2007; (b) aged 18 years or older; and (c) enrollees of health plans that send pharmacy claims data to the claims database. The first 100 patients on this list who were found in the claims database were included in the study sample. Patient-reported current medication information recorded on the medical center's admission medication reconciliation form was compared with the current medication information in the claims database at the time of admission. Medications, including prescription drugs, over-the-counter (OTC) products, supplements, and herbals, were considered current in the medication reconciliation form based on patient reports of medications still being taken upon admission to the medical center. Medications were considered current in the claims database if the most recent fill date plus days supply was equal to or greater than the hospital admission date. Data were collected by an investigator on a standardized data collection form designed for this evaluation. The investigator gathered information from the medical center for each study patient and then queried each patient in the claims database to record data. These 2 medication lists were matched, and discrepancies were noted both at the patient-drug level and at the patient level. Rates of omissions and discrepancies were calculated for each information source, and the McNemar chi-square test for binomial proportions in matched-pair data was used to assess the statistical significance of differences between information sources. RESULTS: Of the 100 patients, a total of 78 patients had medication reconciliation records in their medical center charts that could be compared with claims data. A total of 280 medications were listed for these 78 patients, with 196 medications recorded in the claims database and 131 recorded on the medication reconciliation form. At the patient-drug level, significantly more medications and strengths were listed in the claims database than in the medication reconciliation form (medications: 70.0% of 280 vs. 46.8% of 280, respectively; strengths: 100.0% of 196 vs. 71.8% of 131, respectively; both comparisons P less than 0.001). One-half of the medications omitted in the claims database (42 of 84) were OTC medications. On a patient level, there was no significant between-source difference in the proportion of patients who had at least 1 missing medication (44.9% claims vs. 52.6% medication reconciliation form, P=0.337), but there was a significant difference in the proportion of patients for whom at least 1 strength was missing (0.0% claims vs. 23.1% medication reconciliation form, P less than 0.001). All medications a