When just numbers aren't enough
By Mark Dantos
Numbers may not lie, but they don't always tell the whole story. So before caregivers rely on prescription refill rates to identify mental- health patients at risk of relapse, they should consider all the facts, says a DMS study in the June issue of Psychiatric Services.
Other studies have shown that as many as 40% of those with serious mental illness may sometimes fail to take their prescribed medications. And as such patients' adherence to their antipsychotic regimens declines, their risk of hospitalization rises. But using pharmacy data to assess adherence "is not exactly as perfect as one would think," says the study's lead author, Emily Woltmann, M.S.W. "We wanted to see how imperfect it is."
Charts: Woltmann, a DMS graduate student in health policy and clinical practice, led a team that identified, from electronic medical records, 1,712 veterans with schizophrenia or bipolar disorder whose refill rates fell below a certain threshold. Then the researchers examined the same patients' charts. And they found that in 17% of cases, refill rates were low not because patients had neglected their prescriptions but for less obvious reasons. A doctor may have discontinued a medication by making a chart notation, but without changing the official prescription record, Woltmann explains. Or patients may have moved or transferred their care elsewhere.
While the data for the study was collected in Michigan, the analysis was completed at Dartmouth, she notes. The patients included in the study all had refill rates—known as medication possession ratios (MPRs)—that fell below 80%; candidates with MPRs above 80% were judged "adherent" and not included in the 1,712 cases analyzed.
MPRs can be useful in the aggregate, though. For example, the paper notes that pharmacy data may be a good first screen to identify patients who need help with medication adherence. But it's still important, says Woltmann, to get the patient and the caregiver "in the same room" to get all the facts. Not just the numbers.
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