BACKGROUND  The Iowa Medicaid Pharmaceutical Case Management (PCM) program was established (October 2000) for individuals thought to be at high risk to experience adverse medication effects.^1,2  Eligible patients (non-nursing home and taking four or more medications) were identified from Medicaid pharmacy claims.

OBJECTIVE  To describe the prevalence of medication safety problems among Medicaid beneficiaries taking four or more medications.

METHODS  There were 3,037 PCM-eligible Medicaid beneficiaries from 117 participating pharmacies during the first year of the program.  PCM eligibles were surveyed by mail before receiving PCM services.  Survey measures included general health status (Medical Outcome Study Short-form 36 (SF36)) and self-reported adverse drug reactions in the past 12 months.  Hospitalizations and emergency room visits in the prior 12 months were identified from Medicaid claims.  A list of drugs (from pharmacy claims) that were considered “active” was generated for the date the patient became eligible for PCM.  Medication safety measures applied to the active drug list included major drug-drug interactions and high-risk medications for those age 65 and over.³  A structured review of 507 PCM participating patient charts recorded ten domains of medication safety problems.⁴ 

RESULTS  The mean (SD) age of PCM-eligible patients was 52.5 (±20.2) years and the mean number of active drugs was 7.3 (±3.7).  Drug-drug interactions were detected among 35% of baseline active drug lists.  Approximately 75% of adults over age 65 who were taking antihypertensive drugs had major potential drug-drug interactions.⁵  The prevalence of high-risk medications among those aged 65 and over was 38.3%.  Medication safety problems were detected for 93% of active drug lists and 48.6% of medications using structured chart review.  The self-reported twelve-month baseline prevalence of adverse drug reactions was 27%.  The mean SF36 physical summary score was 17 points (±10.6) below the mean US population normed score of 50 (SD10) and the mean (SD) SF36 mental summary score was 6.8 points (±11.5) below the population mean.  ER visits were identified for 23.9% of PCM eligibles and hospitalizations for 11.3%.

CONCLUSION  The prevalence of adverse drug reactions was three times that in a population-based sample of elders,⁶  physical health status was substantially below the US population mean, and use of high-risk medications was much higher than community-dwelling and general Medicaid samples.⁷  Nearly all patients had at least one medication safety problem.  High-risk medication use among Medicaid patients taking four or more medications is a public health issue of significant importance.