In the hospital setting, it is vitally important that patients understand their medication regimen. Patients are often the primary source of information when physicians take a medication history for medication reconciliation. If patients don’t understand their preadmission medication regimen, their risk for errors in inpatient and post-discharge medication orders increases.

“Lower health literacy, impaired cognition, and a higher number of medications can affect the accuracy of patient-reported medication regimens.”

Few studies have examined how well patients understand their preadmission medication regimen and the factors that affect understanding. Low health literacy, advanced age, and impaired cognitive function all have the potential to adversely affect understanding of medication instructions. To address gaps in research, my colleagues and I conducted a study that was published in the November 2011 Journal of Hospital Medicine in which we examined how certain patient factors affected understanding of preadmission medication regimens.

Predictors of Medication Understanding

In our analysis, 790 patients from Vanderbilt University Hospital and Brigham & Women’s Hospital were eligible for the investigation. We found that 21% of participants had marginal or inadequate health literacy. Also, the median number of medications that they were taking was eight. The following were each independently associated with less understanding of the purpose, dose, and/or frequency of their preadmission medication regimen:

Lower health literacy.

Lower cognitive function.

Higher number of medications.

Furthermore, we found that for each increase by one medication, there was a significant decrease in medication understanding. Patients on six medications were about half as likely to understand their medication regimen as patients on only one medication. For patients on 11 medications, the odds of medication understanding were 24% lower than for those of patients on six medications.

Important Implications When Gathering Medication History

It’s important for clinicians to take precautions when gath­ering medication histories from patients who cannot readily provide the purpose, strength, units, and frequency of their medications. We should also strive to validate the informa­tion we get from patients with other sources of data, such as family members, inpatient or outpatient health records, and community pharmacy records.

Our study has other clinical implications. For example, the relationship observed between the number of medications and medication understanding has potential implications for prescribing practices. Patients at high risk for poor medication understanding may warrant more intensive medication reconciliation interventions as well as educa­tional counseling and follow-up to prevent adverse drug events after they’re discharged.


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