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Evidence Gap Stymies Research into Global Opioid Overuse

New research finds that while the use of opioids for non-chronic pain is widespread, information on the dose and duration of opioids in cases outside the United States is insufficient.

Investigators discovered a dramatic worldwide increase in the use of opioid medications on non-cancer pain over the last 25 years. Yet, only a small number of studies on the impact of this very addictive medication have been performed outside the U.S. In the current study, researchers from the University of Sydney investigated the worldwide use of opioids for chronic pain related lower back pain, osteoarthritis and rheumatoid arthritis.

The researchers note that while the Center of Disease Control and Prevention has developed guidelines to discourage the use of opioids to manage chronic non-cancer pain, few other countries have taken this step. The CDC guidelines reflect concerns about harmful effects and the lack of evidence about effectiveness of opioids to manage chronic pain in a non-addictive manner.

Investigators performed a systematic review of studies from across the world to examine the literature about the extent opioid pain relievers are being prescribed to manage people with chronic pain conditions.

The research spanned eight countries and evaluated 42 published studies that included 5,059,098 people with chronic pain conditions (other than cancer). Two-thirds of the studies were from the U.S.; one study was from Australia and the other studies were from the United Kingdom, Norway, India, Spain, Denmark and Canada.

Lead author Dr. Stephanie Mathieson from the University of Sydney’s Institute for Musculoskeletal Health, said that in the period 1991-2015, prescribing of opioid medicines increased markedly. In the early studies, opioid medicines were prescribed to about 20 percent of patients experiencing chronic pain but the later studies report rates of more than 40 percent.

“Over this period, on average around 30 percent of people with chronic pain were prescribed an opioid medicine,” said Mathieson.

“We noted that a higher proportion of people were prescribed a strong opioid medicine such as oxycodone compared to weak opioid pain-relieving medicines.”

The authors also discovered there was insufficient data on the dose and duration of opioids prescribed to patients with chronic non-cancer pain.

Key findings regarding opioid prescribing for those with chronic pain (unrelated to cancer):

  • prescribing increased over time from approximately 20 percent in early years to around 40 percent in later years;
  • on average over this period approximately one in three patients (30.7 percent) were prescribed an opioid medicine;
  • 42 percent of patients with chronic lower back pain were prescribed an opioid;
  • the average age of those prescribed an opioid medicine was 55.7 years;
  • prescribing was not associated with the geographical location or the clinical setting where the opioids were prescribed (such as GPs or medical specialists).

Types of opioid painkillers (In 17 studies that described the type of opioid pain relievers prescribed):

  • 24.1 percent were strong combination products containing opioids (eg oxycodone plus paracetamol, brand name Tylenol);
  • 18.4 percent were strong opioids (eg oxycodone, morphine, fentanyl);
  • 8.5 percent were weak opioids (eg codeine, tramadol);
  • 11 percent were weak combination products containing opioids (e.g., codeine plus paracetamol).

Researchers explain the findings suggest an evidence gap in global prescription data. The study aimed to establish a baseline for how commonly opioids are prescribed for people with chronic pain conditions (other than cancer). But the authors discovered a crucial evidence gap in prescription data in countries outside of the US.

This research is a collaboration between the University of Sydney; the University of Warwick, UK; the University of Notre Dame; the University of New South Wales and Monash University.

Source: University of Sydney/EurekAlert

Evidence Gap Stymies Research into Global Opioid Overuse

Rick Nauert PhD

Rick Nauert, PhDDr. Rick Nauert has over 25 years experience in clinical, administrative and academic healthcare. He is currently an associate professor for Rocky Mountain University of Health Professionals doctoral program in health promotion and wellness. Dr. Nauert began his career as a clinical physical therapist and served as a regional manager for a publicly traded multidisciplinary rehabilitation agency for 12 years. He has masters degrees in health-fitness management and healthcare administration and a doctoral degree from The University of Texas at Austin focused on health care informatics, health administration, health education and health policy. His research efforts included the area of telehealth with a specialty in disease management.

APA Reference
Nauert PhD, R. (2020). Evidence Gap Stymies Research into Global Opioid Overuse. Psych Central. Retrieved on September 27, 2020, from
Scientifically Reviewed
Last updated: 27 Feb 2020 (Originally: 28 Feb 2020)
Last reviewed: By a member of our scientific advisory board on 27 Feb 2020
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