First-of-its-kind research at the Minneapolis VA has found no long-term benefits for patients taking opioid medications for chronic pain — a finding that is likely to strengthen the case for reducing use of the addictive medications that have been responsible for a sharp rise in drug overdoses and deaths.

Focusing on patients who suffer from chronic back pain or arthritic knees and hips, the study compared 120 who didn’t receive opioids with 120 who did as part of their pain management. After a year, pain levels dropped by the same amount in both groups, and pain intensity decreased more in those who didn’t receive opioids such as hydrocodone or oxycodone.

Meanwhile, treatment-related complications were more common in the opioid group.

“The data don’t support opioids’ reputation as painkillers,” said Dr. Erin Krebs, who led the study, called Strategies for Prescribing Analgesics Comparative Effectiveness (SPACE). She presented the findings Wednesday at the annual research day at the Minneapolis VA Medical Center, and in April to the Society of General Internal Medicine.

Krebs’ findings could influence state and federal policies on opioid prescribing. A Minnesota task force has debated over the past year whether to discourage the use of opioids for patients with chronic pain, largely because of the relative lack of evidence that the drugs work for such patients.

“This is a valuable reinforcer of what our group is moving to,” said Dr. Chris Johnson, a member of the opioid task force and a leading critic of opioid prescribing. “And if pain doctors still think these medicines are effective, then they have a lot of explaining to do, and their competence and professionalism deserve to be challenged.”

Attitudes about opioid medications and their addictive hazards evolved so rapidly over the five years of the study that Krebs said she isn’t sure a follow-up study would receive ethical clearance today — to keep one group of chronic pain patients on opioids. It wasn’t always so. At first, critics raised the opposite question: the ethics of denying half the study group access to opioids.

“This was an incredibly challenging trial to execute,” Krebs said, noting that at the outset 37 percent of the patients placed in the non-opioid group actually wanted those drugs for their pain.

Attitudes changed in part because of a startling increase in overdose deaths from prescription opioids or illicit versions such as heroin. Even in Minnesota, where doctors have long been more conservative in their opioid prescribing, the number of deaths rose from 56 in 2000 to 336 in 2015, according to a Star Tribune analysis of state death certificate data.

Deaths and inpatient treatment admissions for opioid addiction started to increase in the United States after 1999 — shortly after the American Pain Society deemed pain to be the fifth “vital sign” that required medical management. The rising rate of deaths tracks uniformly with the increase in U.S. opioid prescriptions — which Johnson said was promoted by drugmaker Purdue Pharma through its “pain management education program.”

‘Shocking’ prescriptions

Krebs said she laments that her research didn’t take place two decades ago, before the broader use of opioids. Around that time, she had completed her residency at the University of Minnesota and the Minneapolis VA, and taken a fellowship in North Carolina.

She said she was struck by the more aggressive use of opioids in that state, and the relative lack of evidence at the time over their effectiveness.

“It was actually shocking,” she said.

That lack of evidence — and the disparity in prescribing across states — inspired her career-long research interest in pain management. Now, Krebs said, there is a particular need for studies to determine which non-opioid forms of pain management work best.

“We have to move on that parallel track of actually improving pain care,” she said. “Perhaps yoga works, but who should teach it? How many classes should you have” for maximum pain control?

Opioid medications are still considered effective for acute pain after injuries or surgeries. The state opioid prescribing work group, though, has advised that doctors prescribe only three-day supplies or 20 pills at a time. It also advises doctors to check a state monitoring database to make sure patients don’t have histories of drug abuse or of shopping among doctors for opioid prescriptions.

Opioids remain some of the most commonly prescribed drugs in the state, according to the Drug Abuse Trends Report by local substance abuse expert Carol Falkowski.

However, the number of prescriptions in Minnesota is dropping. In December 2014, pharmacists dispensed 113,656 prescriptions of hydrocodone paired with acetaminophen, compared with 87,962 prescriptions last December.