STANFORD, Calif., Dec. 14 (UPI) -- The overprescription of opioid painkillers is being driven by a large number of general practitioners, not by specialists or "pill mill" operations as many have suggested, researchers found in a new study.
The study, conducted at Stanford University, contradicts theories and efforts spanning several years to shut down corrupt clinics handing the drugs out to anybody who asks.
A previous 2011 study showed 1 percent of prescribers accounted for about one-third of opioid prescriptions nationally and the top 10 percent made up 80 percent of prescriptions, researchers said.
Efforts since at least that year have been made to reduce the number of prescriptions, such as a law passed in 2010 in Florida -- where millions of pills were being prescribed by doctors who operated pharmacies out of their offices, earning the nickname "pill mills." A study released in October found the law produced a 1.4 percent decrease in opioid prescriptions from 2010 to 2012, showing shutting them down had a modest effect at best.
Stanford researchers said their study shows law enforcement efforts to go after the biggest prescribers are not enough to reduce overprescription, whether they have legitimate treatment goals in mind or not.
"Being a physician myself, I am acutely aware of the emotional angst that can occur when deciding whether to prescribe opioids to a patient who may have simultaneously developed a chronic-pain and substance-dependence problem," said Dr. Jonathan Chen, a professor at Stanford, in a press release. "The public health epidemic of opioid overuse is perhaps not surprising given the tenfold increase in volume over the past 20 years."
Researchers in the Stanford study, published in the Journal of the American Medical Association, analyzed data for all Schedule 2 opioids in 2013, such as hydrocodone and codeine, covering 381,575 prescribers and 56.5 million claims for prescriptions.
They found the top ten percent of opioid prescribers accounted for 57 percent of opioid prescriptions, which resembles the Medicare pattern for all drugs of the top 10 percent accounting for 63 percent of prescriptions.
The most prescriptions came from family practitioners, internal medicine practitioners, nurse practitioners, and physician assistants.
"These findings indicate law enforcement efforts to shut down pill-mill prescribers are insufficient to address the widespread overprescribing of opioids," Chen said. "Efforts to curtail national opioid overprescribing must address a broad swath of prescribers to be effective."