Previous studies have found higher spending on substance use disorder treatments occurring in Medicaid expansion states compared to non-expansion states. Between 2010 and 2017,Medicaid spending on opioid use disorder treatments increased from $190 million to $887 million, according to an analysis released last February by the Urban Institute.
According to the study, Medicaid expansion states were associated with an 11% lower rate of death from heroin and a 10% decreased mortality rate from synthetic opioids such as fentanyl compared to states that opted not to expand the program.
But expansion states were also tied to an 11% higher rate of overdose deaths from methadone, which Cerdá said was likely because Medicaid beneficiaries were more likely to receive methadone as a pain treatment, increasing their exposure to the drug and putting them at greater risk of overdose.
The use of methadone for the treatment of pain made up 1% percent of all short- and long-acting opioid prescriptions in 2014 yet accounted for an average of 35% of long-acting and extended-release opioid prescriptions in Medicaid between 2013 and 2016, according to a 2018 Pew Charitable Trusts analysis.
Methadone prescriptions to treat pain were responsible for 23% of all opioid-related overdose deaths related to prescription drugs in 2014, according to the Pew analysis. The high mortality rate was due to the physiological effects of the drug, such as respiratory depression, which lasted longer than the duration of pain-relief. Patients put themselves at risk by taking additional doses of methadone once the pain subsided before their original dose was fully absorbed.
"As states expand access to Medicaid, thinking carefully about safety concerns associated with the use of methadone to treat pain is important," Cerdá said.
State Medicaid programs have played an essential role in the nationwide effort to address the opioid epidemic, paying for more than one-fifth of substance use disorder treatment services in 2014.
The range of services most state programs offer include inpatient and outpatient detoxification, intensive outpatient and residential rehabilitation programs.
In 2017, nearly 2 million adults in the U.S. had an opioid use disorder, and of those individuals, nearly four in 10 were covered by Medicaid, according to figures from the Kaiser Family Foundation.
A KFF issue brief released last May found Medicaid beneficiaries were nearly twice as likely than those with private insurance to have received substance use disorder treatment in 2017. An estimated 44% of beneficiaries received treatment in 2017 versus 24% of individuals covered by private health plans.