Aussie researchers followed more than 1500 people with pain over five years… what did they find?
Contrary to predominant thinking in pain management, there is considerable fluidity in opioid use over time among many patients with chronic non-cancer pain who use opioids, according to new research published in JAMA Network Open.
Led by the National Drug and Alcohol Research Centre (NDARC) based in UNSW, Sydney, the prospective cohort study included 1514 adults who were prescribed opioids for chronic non-cancer pain.
This cohort was interviewed several times between 2012 and 2018: at baseline, at three months, and annual interviews thereafter for five years.
Participants were aged 18 years or older, living with pain lasting longer than three months, and were taking prescribed S8 opioids including morphine, oxycodone, buprenorphine, methadone and hydromorphone for chronic non-cancer pain for more than six weeks.
Participants reported living with pain condition for a median (IQR) of 10.00 (4.54-20.00) years and had a median (IQR) of 2.00 (1.00-3.00) chronic non-cancer pain conditions in the past 12 months.
The most common pain conditions were back or neck problems followed by arthritis.
Researchers from NDARC uncovered some interesting findings.
The data revealed some cohort members who had not engaged in problematic opioid behaviors at one interview reported doing so at the next interview, while some who had engaged in a particular behaviour in an earlier interview had ceased in the following interview.
Approximately one in eight individuals (from 10.98% to 14.73%) were taking 200 oral morphine equivalent (OME) mg/d or more at each interview.
At any given interview, comparatively more (from 8.46% to 23.77%), had requested an increase in dose at least once in the past three months.
Meanwhile fewer asked for an early prescription renewal (from 4.61% to 13.97%) at each interview.
Having ceased taking opioids at a given interview increased across interviews, from 9.15% in the first year to 20.02% in year five.
Prevalence of tampering or diversion was very low in the cohort; in any given interview, between 3.06% and 7.86% of respondents reported tampering at least once in the past three months, and between 0.47% and 1.39% of respondents reported diversion at least once in the past three months.
“Again, there was substantial variation over time in which individuals engaged in these behaviours,” said the researchers.
For example, for pharmaceutical opioid dependence, between 55.26% and 64.44% of cases in one interview did not meet dependence criteria in the following interview.
“Given the comparatively high incidence and cessation across interviews, most who engaged in these behaviors only did so at one interview. Very small percentages of the cohort engaged in any of the behaviors on two or more interviews,” they said.
There were some patterns noted. Individuals who were unemployed or retired were significantly less likely to cease opioid use.
Other variables associated with being less likely to cease opioid use included having a lower capacity to cope with pain based on the pain self-efficacy, having a high pain interference score or taking 200mg OME or more per day.
However although prevalence of opioid use, problematic opioid use and harm behaviors was reasonably consistent at each interview, such behaviours typically did not reflect stable patterns within individuals over time and typically occurred at only one or perhaps two points across the five years of follow-up, the researchers said.
“This suggests that problematic opioid use behaviors are typically dynamic and time limited even among a cohort of people with longstanding chronic non-cancer pain, long-term prescribed opioid use, and multiple physical, mental health, and substance use disorder comorbidities.
“These findings challenge the approach of assessing risk for adverse opioid behaviors based on static risk factors at the commencement of treatment and reinforce the need for constant individual reassessment of the effectiveness and safety of prescription opioid use,” they concluded.
Read the full article in JAMA Network Open here