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  • Publication # 13-RA012

Automated tool to determine medication regimen complexity may help identify patients at high risk of adverse events

Patient Safety and Quality

Poor adherence to recommended medication treatment plans has been associated with adverse consequences for patients and higher costs. A contributing factor to poor adherence is the complexity of a medication regimen, according to a number of studies. 

Use of a medication regimen complexity index (MRCI), a tool for quantifying multiple features of drug regimen complexity, together with a medication database, could help to identify patients who are at higher risk of adverse events, suggests a new study. To reliably quantify medication regimen complexity, the MRCI extracts information found in patient charts and prescriptions, and assigns weights to dosage forms, dosing frequencies, and additional instructions.

Image of Pill BottleThe authors describe the process of adapting an MRCI, previously developed by other researchers, for use at the Visiting Nurse Service of New York (VNSNY), the largest non-profit Medicare/Medicaid-certified home health organization in the United States. 

In the first phase, the researchers abstracted medication data from 89,645 electronic health records to line up with the MRCI’s components: dosage form, dosing frequency, and additional instructions. A committee reviewed output to assign index weights and determine necessary adaptations. In the second phase, the authors examined the face validity of the modified MRCI through analysis of automatic tabulations and descriptive statistics. The MRCI tool was then translated for use within the VNSNY’s electronic health record system.

The result was the first comprehensive quantitative data on medication regimen complexity in a large population of post-acute care patients characterized by multiple conditions and medical complexity. The researchers found that most patients (55 percent) were taking medications in only one route/form (tablet or capsule), although 16 percent had regimens with three or more medications with different routes or forms. The biggest contributor to the MRCI score was dosing frequency. Over 36 percent of patients needed to remember two or more special instructions (e.g., take on alternate days, dissolve). 

The researchers anticipate that, at some point, automated MRCI scores can be linked to patient outcome data to determine risk thresholds for adverse events. This study was supported by AHRQ (HS17837).

See "Automating the medication regimen complexity index," by Margaret V. McDonald, M.S.W., Timothy R. Peng, Ph.D., Sridevi Sridharan, M.S., and others in the May 1, 2013, Journal of the American Medical Informatics Association 20(3), pp. 499-505.


Page last reviewed September 2013
Internet Citation: Automated tool to determine medication regimen complexity may help identify patients at high risk of adverse events: Patient Safety and Quality. September 2013. Agency for Healthcare Research and Quality, Rockville, MD.


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