Image Credit: Shutterstock

VANCOUVER - The number of people using prescription opioids long-term in British Columbia was growing at a "silent but steady" rate for years before the current overdose crisis erupted, a new study has found.

Researchers at the University of British Columbia show that between 2005 and 2012, there was a steady increase in the use of prescription opioids for treatment periods lasting three months or longer, excluding cancer treatment or end-of-life care.

Kate Smolina, a medical researcher and the study's primary author, said the percentage of long-term opioid users in B.C. jumped from two per cent of the total population to 2.4 per cent within that eight-year period. That's a jump of only 0.4 percentage points, but a relative spike of 19 per cent.

"Two per cent may sound like it's not very much, but it's actually quite a bit. In B.C., it translates to about 100,000," Smolina said.

Opioid use became a major concern in B.C. this year, as 755 people died from illicit drug overdoses between January and the end of November. The BC Coroners Service has said the powerful opioid fentanyl was detected in about 60 per cent of the deaths.

Smolina's study aimed to understand the numbers, patterns and frequencies of long-term prescription opioid use in B.C. It revealed that while the number of new users every year is stable, the total number of people using prescription opioids is growing.

For every 19 people who began long-term use of opioids, 16 existing users stopped therapy, Smolina said.

"To provide some context, the number of new users is generally comparable to the number of people who are newly diagnosed with diabetes every year in B.C., or about three times the number of people hospitalized for stroke or heart attack," said Smolina, who now works for the B.C. Center for Disease Control.

The research also showed that 10 per cent of patients using the drugs long-term — excluding those in palliative care or who are suffering from cancer — account for 67 per cent of all opioid prescriptions, or 87 per cent of what Smolina referred to as "morphine equivalents." The unit is used to standardize the various types of opioid drugs for comparison.

The research found that about a quarter of everyday users consume at least 200 morphine equivalents of opioids per day.

The amount exceeds the 120 morphine equivalents recommended as a "watchful dose" in the prescription guidelines of the United States Centre for Disease Control and the B.C. College of Physicians and Surgeons.

"Two-hundred is very high ... multiple times over what the starting dose would be," Smolina said. "You don't want to go there. And if you are there, you try to taper (a patient) from that."

Opioids are effective short-term pain management, but the absence of evidence for their effectiveness as long-term pain treatment — and evidence of long-term harm — suggests the government needs to invest in alternative treatments, she said.

"The lesson here is that we have the acute problem of overdoses on the streets, but I also want to bring light to the fact that there's also this silent but steady other problem that's growing, which are these patients who are dependent on opioids," Smolina said.

"It's becoming more and more of them — and invariably some will turn to (the street)."

— Follow @gwomand on Twitter

News from © The Canadian Press, 2016