WASHINGTON, March 19, 2013 /PRNewswire-USNewswire/ -- Even when supported by patient-centered prescription information and services, a substantial proportion of patients who say that they fill their prescription medicines do not, according to a study published online last Friday in Annals of Emergency Medicine ("The Validity of Self-Reported Primary Adherence Among Medicaid Patients Discharged from the Emergency Department with a Prescription Medication"). (Logo: http://photos.prnewswire.com/prnh/20100616/DC22034LOGO-d) "When patients told us they did not fill their prescription medication, this was likely to be true, regardless of type of drug," said lead study author Melissa McCarthy, ScD., of George Washington University in Washington, D.C. "However, when patients said that they filled their prescription, there was frequently no pharmacy claims record to support this. Among patients who told us they filled their prescription, it is challenging to identify those who actually did not." Researchers analyzed records for 1,026 Medicaid patients who were prescribed at least one medication at discharge from the emergency department. Medication was either by prescription only or over the counter. Although patients reported filling 90 percent of prescribed medications overall, the pharmacy reported that only 74 percent of them were filled. "Some of the discrepancy between self-report and pharmacy claims is likely due to over-the-counter medications being filled without using the pharmacy benefit," said Dr. McCarthy. "We observed a smaller gap between self-report and pharmacy claims for prescription medications (13 percent) than for over-the-counter medications (24 percent)." The relationship between numerous patient and clinical factors and the accuracy of the self-reported prescription filling rates were examined but few factors were associated with patients saying they had filled the prescription when they had not. "One group of patients who were less likely to tell us that they had not filled their prescription were patients with at least one recent ER visit," said Dr. McCarthy. "These patients may be more likely to confuse which prescriptions they filled if they were issued multiple prescriptions by different providers. What is clear from this research is that emergency patients over-report prescription filling."