Inpatient medication reconciliation at admission and discharge: A retrospective cohort study of age and other risk factors for medication discrepancies

Background: Medication discrepancies are unintended differences between medication regimens (ie, between a patient's home regimen and medications prescribed on admission to the hospital).

Objective: The goal of this study was to describe the incidence, drug classes, and probable importance of hospital admission medication discrepancies and discharge regimen differences, and to determine whether factors such as age and specific hospital services were associated with greater frequency of medication discrepancies and differences.

Methods: This was a retrospective cohort study of a random sample of adult patients admitted to the general medicine, cardiology, or general surgery services of a tertiary care academic teaching hospital between July 1, 2006, and August 31, 2006. A chart review was performed to collect the following information: patient demographic characteristics, comorbid conditions, number of preadmission medications, discrepant medications identified by the hospital's reconciliation process, reasons for the discrepancies, and discharge medications that differed from the home regimen. Potentially high-risk discrepancies and differences were identified by determining if the medications were included on either the Institute for Safe Medication Practices high-alert list or the North Carolina Narrow Therapeutic Index list. Univariate and multivariate logistic regression analyses were used to identify factors associated with medication discrepancies and differences.

Results: Of the 205 patients (mean age, 59.9 years; 116 men, 89 women; 60% white) included in the study, 27 did not have any medications recorded on admission. Of the 178 patients who did have medications listed, 41 had >or=1 discrepancy identified by the reconciliation process on admission (23%; 95% CI, 17-29); 19% (95% CI, 11-31) of these medications were considered to be potentially high risk. In the multivariate logistic regression model, age (odds ratio [OR] per 5-year increase = 1.16; 95% CI, 1.01-1.33; P = 0.035), presence of high-risk medications on admission (OR = 76.68; 95% CI, 9.13-643.76; P < 0.001), and general surgery service (OR = 3.31; 95% CI, 1.40-7.87; P < 0.007) were associated with a higher proportion of patients with discrepancies on admission. At discharge, 196 patients (96% [95% CI, 93<98]) had >or=1 medication change from their home regimen, with 1102 total differences for 205 patients. Less than half (44% [95% CI, 37-51]) of these patients were explicitly alerted at discharge to new medications or dose changes; 12% (95% CI, 7-18) were given written instructions to stop taking discontinued home medications. Cardiovascular drugs were the most frequent class involved at both admission (31%) and discharge (27%) in medication discrepancies or differences.

Conclusions: Medication discrepancies on admission and medication differences at discharge were prevalent for adult patients admitted to the general medicine, cardiology, and general surgery services in this academic teaching hospital. Medication reconciliation processes have a high potential to identify clinically important discrepancies for all patients.