Overdose Deaths Involving Prescription Opioids Among Medicaid Enrollees

During 1999–2006, the number of poisoning deaths in the United States nearly doubled, from approximately 20,000 to 37,000, largely because of overdose deaths involving prescription opioid painkillers (1). This increase coincided with a nearly fourfold increase in the use of prescription opioids nationally (2). In Washington, in 2006, the rate of poisoning involving opioid painkillers was significantly higher than the national rate (1). To better characterize the prescription opioids associated with these deaths and to reexamine previously published results indicating higher drug overdose rates in lower-income populations (3), health and human services agencies in Washington analyzed overdose deaths involving prescription opioids during 2004–2007. This report describes the results of that analysis, which found that 1,668 persons died from prescription opioid-related overdoses during the period (6.4 deaths per 100,000 per year); 58.9% of decedents were male, the highest percentage of deaths (34.4%) was among persons aged 45–54 years and 45.4% of deaths were among persons enrolled in Medicaid. The age-adjusted rate of death was 30.8 per 100,000 in the Medicaid-enrolled population, compared with 4.0 per 100,000 in the non-Medicaid population, an age-adjusted relative risk of 5.7. Methadone, oxycodone, and hydrocodone were involved in 64.0%, 22.9%, and 13.9% of deaths, respectively. These findings highlight the prominence of methadone in prescription opioid-related overdose deaths and indicate that the Medicaid population is at high risk. Efforts to minimize this risk should focus on assessing the patterns of opioid prescribing to Medicaid enrollees and intervening with Medicaid enrollees who appear to be misusing these drugs.

For this analysis, the Washington State Department of Health defined an overdose death involving prescription opioids as a death in Washington during 2004–2007 of a state resident whose death certificate had 1) a manner of death of “accidental” or “natural”; 2) one or more contributing causes coded to “poisoning by narcotics” or a “mental and behavioral disorder due to use of opioids” (based on International Classification of Diseases, 10th Revision codes T40.0–T40.6 and F11*); 3) specific words compatible with an acute drug intoxication recorded in any of the cause of death fields (e.g., “overdose”); and 4) a prescription opioid term in any of the cause of death fields. Examples of prescription opioid terms sought on manual review of the certificates were “oxycodone,” “methadone,” and “hydrocodone.” Although morphine is a prescription opioid painkiller, it is also a metabolite of heroin. Therefore, mention of morphine on a death certificate was only accepted as evidence that death was prescription opioid-related when the certificate specified that the morphine was a prescription drug. As a result, 82 deaths involving morphine and no other opioids (36.6% of all deaths in which morphine was mentioned) were excluded from this analysis.

The Washington State Health and Recovery Services Administration (WSHRSA), which operates Medicaid and several associated medical-assistance programs, determined which deaths occurred among persons who were enrolled in Medicaid at some time during the year of their death. During 2004–2007, the Medicaid-enrolled population (5,109,363 person-years) represented 20.2% of the Washington population (25,287,800 person-years). WSHRSA also linked the deaths from prescription opioids to records of clients in the Medicaid Patient Review and Coordination (PRC) program, a special state program for clients who overuse or inappropriately use medical services. PRC program members (5,858 person-years) represented 0.1% of the Medicaid population during 2004–2007. Rates were age-adjusted because the Medicaid population was younger than the non-Medicaid population.

During 2004–2007, a total of 2,282 deaths in Washington met the manner and cause of death case definition criteria. Of these, 2,194 (96.1%) had a death certificate that included a term indicating acute drug intoxication. Of these 2,194, a total of 1,668 (76.0%) had a death certificate that included a prescription opioid term and were included in this analysis. The age-adjusted prescription opioid overdose rate was 6.4 per 100,000 per year (Table 1). The male mortality rate was 1.4 times the female rate. Rates increased with age to a peak of 15.0 per 100,000 in the 45–54 years age group and then declined.

Among all decedents, 758 (45.4%) were enrolled in Medicaid at some point during the year of their death. Medicaid-enrolled decedents had an age distribution comparable with that of decedents statewide. However, the percentage of females was greater among Medicaid-enrolled decedents (52.2%) than among decedents statewide (41.1%). A total of 34 Medicaid-enrolled decedents were in the PRC program, representing 4.5% of all Medicaid-enrolled decedents.

The risk for prescription opioid overdose death varied substantially by Medicaid status (Table 2). The crude annual risk for prescription opioid overdose death was approximately one in 6,757 in the Medicaid-enrolled population and one in 172 in the Medicaid-enrolled PRC program population.

Medical examiners and coroners recorded methadone on death certificates nearly three times more often than the next most common opioid, oxycodone (Table 3). At least one nonopioid prescription drug was reported in 54.6% of the deaths. A benzodiazepine was listed on the death certificate in 20.9% of the deaths, and an antidepressant in 31.7%. An illegal drug was reported in 21.8% of the deaths. Cocaine was involved in 15.7%, methamphetamine in 5.5%, heroin in 2.4%, and alcohol in 17.1% of the deaths. More than one drug was listed for 72.3% of decedents. The mean and median numbers of drugs per death were 2.7 and 2.0, respectively.

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