Examining a national database of health insurance claims, researchers found that 91 percent of patients who suffered a nonfatal overdose of prescription opioid painkillers continued getting prescriptions for opioids following the overdose. And, the researchers found, overdose survivors who kept taking high dosages of an opioid—including morphine, oxycodone, and hydrocodone—were twice as likely to have another overdose within two years.

The findings, published in the Annals of Internal Medicine, follow news earlier this month from the Centers for Disease Control and Prevention that drug overdoses, opioid overdoses in particular, have reached epidemic levels. The fact that patients surviving opioid overdoses are still being prescribed opioids is “highly concerning,” the authors of the new study wrote.

In a press release, lead author Marc LaRochelle of Boston Medical Center said that "[t]he intent of this study is not to point fingers but rather use the results to motivate physicians, policy makers and researchers to improve how we identify and treat patients at risk of opioid-related harms before they occur."

From 2000 to 2014, the rate of overdose deaths involving opioids (including prescription opioids and heroin) increased by 200 percent, the CDC reported. Although there’s been a recent surge in deaths from heroin overdose, deaths from prescription opioid painkillers make up the lion’s share of opioid deaths. In fact, opioid painkillers were involved in more overdose deaths than any other opioids. In 2013, 16,235 people died of overdoses of opioid prescription painkillers.

In the new study, researchers examined insurance claim data on 50 million people filed between 1999 and 2010. The researchers picked out information from nearly 3,000 patients who were prescribed an opioid for chronic pain and were, at some point in the 12-year period, treated for a nonfatal opioid overdose.

In claims from follow-up treatment, the researchers found that nearly all—91 percent—of the overdose survivors continued to receive opioid painkiller prescriptions. And for 70 percent of overdose survivors that stayed on opioids, those continued prescriptions were written by the same doctor who prescribed opioids before their first overdose.

It’s unclear from the data why doctors would keep prescribing opioids after an overdose. According to the authors, it may be because doctors don’t know about a patient’s overdose, or doctors may have weighed the risks and benefits and decided continued opioid use was appropriate. It’s also possible that some doctors are not equipped to treat opioid-addiction or prescribe opioids in error.

The authors discuss introducing procedures or notification systems to make sure that doctors know if their patient has suffered an overdose, as well as using prescription-monitoring services and making overdose reports to a central health office mandatory.

This month, the CDC issued a draft guidance urging physicians to cut back on opioid prescriptions. Instead, the agency recommends prescribing physical therapy and non-opioid painkillers, as well as periodic urine tests of patients receiving opioid painkillers to make sure they're not abusing prescriptions or illegal opioids.

Annals of Internal Medicine, 2015. DOI: 10.7326/M15-0038 (About DOIs).