A report on opioid use among privately insured Americans has found that diagnoses of opioid addiction increased almost fivefold between 2010 and 2015, ticking up sharply in 2014.

During the same period, the delivery of medication-assisted addiction treatment — the method most likely to result in successful abstinence — grew by just 65 percent.

Exacerbating that gap was a geographic mismatch. The use of treatments that wean people off opiates with drugs such as buprenorphine, naloxone and suboxone was least common in states across the American South and Midwest, where addiction rates were highest. Such treatments were common in states where the opiate addiction epidemic is less severe, including Pennsylvania, New York and New England.

Roughly 30,000 American adults last year died from an opioid drug overdose. That’s on par with the number of Americans killed in motor vehicle crashes each year and more than died from HIV/AIDS at the height of that epidemic. The National Institutes of Health estimate that prescribed opiates were the gateway to addiction for close to three-quarters of new heroin users.

The new report was prepared by Blue Cross Blue Shield, which combed the medical and pharmacy records of 30 million of its members to glean trends in the opiate addiction epidemic. By 2016, Blue Cross Blue Shield reported, nearly 1 percent of its members had been diagnosed with opioid use disorder.

The insurance giant’s records also yielded insights into which patients are most likely to become addicted, and how.

It found that in 2015, roughly one in five privately insured adults in the United States filled at least one prescription for a prescription narcotic painkiller.

Close to half of those patients — 45 percent of those prescribed prescription opioids — received high doses of narcotic painkillers, which were most likely to result in a later diagnosis of addiction disorder.

Pharmacy and medical records showed that the highest rate of addiction disorders was seen in patients who had been prescribed high doses of prescription pain relief medicine for short periods — fewer than 90 days. Fully 6.2 percent of those patients would go on to be diagnosed with an opioid addiction disorder.

Many of those patients got hooked after a physician prescribed a relatively short course of pain medication for appendicitis, osteoarthritis, back or joint pain, or kidney or gallstones.

Right behind them, in terms of addiction risk, were patients who were prescribed high doses of painkillers for more than 90 days, typically for chronic conditions such as arthritis and back pain. Of those patients, 4 percent would eventually be diagnosed with opioid addiction.

Lower doses of opioids, even over a long period, were found to be far less addictive than high doses. But the length of a patient’s treatment with painkillers also escalated the risk of addiction.

The Blue Cross Blue Shield report suggests that the spurt in addiction disorder diagnoses that started in 2014 may have been driven in part by growing recognition of opioid addiction among physicians.

But prescribing practices clearly played a key role. In 2015, the highest density of patients filling prescriptions for opioid narcotics lay in an arc of states spanning Oklahoma, Arkansas, Louisiana, Mississippi and Alabama, with slightly lower rates in Georgia, Tennessee, North and South Carolina, West Virginia and Indiana.

In 2016, physicians in those same states were diagnosing opioid use disorder at extremely high rates.

Blue Cross Blue Shield called opiate addiction “the fifth most impactful condition affecting the health of commercially insured members in the U.S.”

“It will take a collaborative effort of health providers, insurers, communities and all levels of government working together to develop solutions that effectively meet community needs,” the insurance giant said.

The Trump administration has called the opioid epidemic a top priority, and the president has named his former adviser, New Jersey Gov. Chris Christie, to head a commission investigating the matter.

In a June meeting, experts said that Medicaid expansion — a key target of the GOP’s proposed health care revision — is key to the delivery of effective addiction treatment.

Christie’s panel was expected to provide draft recommendations this week. But it has postponed further meetings, and a release of recommendations, until July.