Adverse drug events are a primary cause of hospitalization in the elderly. Nearly 70% of the $177.4 billion dollars spent on drug related morbidity and mortality in the U.S. is due to hospitalizations. Polypharmacy, inappropriate medications or medication regimen complexity have all been implicated as precursors to adverse drug events and as indicators of high risk medication regimens. Understanding the relationship between medication regimens and readmission is important when evaluating potential errors in administration, risk-benefit ratios, and readmission risk. However, due to definitional and measurement issues, the high risk medication regimen remains an elusive concept. This study characterizes medication regimens, defines high risk medication regimens, and determines if high risk medication regimens predict re-hospitalization in home healthcare clients over age 65
