Databases that track prescriptions can keep people from obtaining opioids from multiple physicians. But they will only work if more doctors use them.

One of the best tools to keep people from visiting multiple doctors to obtain prescription opioids would work a whole lot better … if more doctors simply used the system.

New research suggests that so-called “doctor shopping” by Medicare enrollees decreased in states that require doctors to check their patients’ previous prescriptions.

Nearly every state has a Prescription Drug Monitoring Program (PDMP) that tracks all prescriptions for opioids like OxyContin, Percocet, and Vicodin.

This allows doctors and pharmacists to look for signs that patients may be abusing opioids or passing the drugs onto others.

But states vary on how strict their laws are — and that affects how well the databases work.

“The key difference between a PDMP that’s effective vs. one that is not is whether you actually get the provider to engage with it,” said study author Colleen Carey, PhD, assistant professor of policy analysis and management in the College of Human Ecology at Cornell University.

The study, by Carey and co-author Thomas Buchmueller, PhD, professor of business economics and public policy at the University of Michigan, will be published in the American Economic Journal: Economic Policy.

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Telling doctors and pharmacists about the benefits of using a PDMP can encourage them to log in.

But what may work even better are “must access” laws that require prescribers to check a patient’s prescription history in the database.

In Kentucky, prescriber logins jumped from 30 percent to 95 percent two months after a “must access” law was passed.

These laws may also reduce potential opioid misuse.

Carey and Buchmueller looked at Medicare opioid prescription data for 10 states. After they started the study, several more states passed PDMP laws.

In states with “must access” laws, the percentage of Medicare enrollees who obtained prescriptions from five or more doctors was 8 percent lower, compared with other states. The percentage of people getting opioids from five or more pharmacies was 15 percent lower.

States with a “must access” database also saw a decline in the number of Medicare enrollees filling opioid prescriptions before the previous one had run out, or obtaining more than a seven-month supply of opioids in a half-year period.

These states also saw a 15 percent reduction in the number of Medicare enrollees with four or more new patient visits in six months.

Researchers estimate that if every state had a “must access” database, it would save Medicare $348 million annually just in unnecessary new patient visits.

According to the National Conference of State Legislatures (NCSL), 49 states currently have PDMPs, but rules vary on when prescribers have to check them. Some states require that only certain providers check the database under certain circumstances, such as when they suspect opioid abuse or diversion.

Carey and Buchmueller found, though, that PDMPs had the biggest effect in states with the strictest laws, requiring all prescribers to check the opioid history of “every patient, every time.”

A proposal to create a PDMP in Missouri — the lone hold-out — recently stalled in the state’s legislature.

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The Medicare population in the study included both adults over age 65 and younger people on Social Security Disability Insurance (SSDI).

The researchers found that the majority of the effects of “must access” laws were driven by the disabled Medicare population, particularly people who were disabled and had low incomes.

Researchers think this group is representative of the general population.

“The SSDI population is demographically similar to the population that we usually think of as opioid abusers — middle-aged, white, lower education, rural,” said Carey.

Also an estimated 1 in 4 opioid deaths nationally in 2008 were Medicare enrollees, according to a study in the New England Journal of Medicine.

Other studies have seen similar benefits of PDMPs in different populations.

A 2017 study in Health Affairs found that laws requiring doctors to register for, or use the state’s PDMP, resulted in a 9 to 10 percent drop in opioid prescriptions among Medicaid recipients and spending on those prescriptions.

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A 2016 study in Health Affairs saw a drop in opioid-related overdose deaths the year after states implemented a PDMP.

The authors of this study estimate that if Missouri instituted a database and other states enhanced their programs, 600 fewer people would die each year from prescription opioids.

Carey and Buchmueller also found that in states with “must access” laws, opioid poisonings decreased somewhat, but it wasn’t statistically significant.

They suspect this may be because Medicare enrollees that are misusing opioids are finding another source after their state institutes a “must access” database.

They may buy prescription opioids or heroin on the street. Or shop out of state.

“We actually do find some evidence that the rate of people [in a “must access” state] obtaining opioids from an out-of-state prescriber or out-of-state pharmacy goes up,” said Carey.

Neighboring states may have less restrictive PDMP laws, which allows people to go unnoticed.

But a bigger issue is that each state has its own database, so prescriptions filled in one state aren’t always reported in a person’s home state.

“It was a state-based solution to a problem that definitely had an interstate dimension almost from the beginning,” said Carey.

More states are starting to share data between PDMPs, which is cutting down on out-of-state “doctor shopping.” But even the number of people going out of state pales in comparison to the benefits of these databases.

“I think the amount of circumvention was small, relative to the kinds of improvements that we see from these ‘must access’ PDMPs,” said Carey.

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