Study shows high opioid dependence in patients with chronic pain

A new scientific review of 148 studies involving over 4.3 million adult patients with chronic pain treated with prescription opioid painkillers has found that almost one in ten patients suffer from opioid dependence or opioid use disorder, and almost one in three have symptoms of dependence and opioid use disorder. This review provides a more accurate – and worrying – rate of opioid misuse than previously calculated. It was conducted by researchers at the University of Bristol, funded by the National Institute for Health and Care Research (NIHR) and appears in the scientific journal Seeks.

Companies like Oxycontin maker Purdue Pharma have claimed that less than 1% of opioid prescriptions result in problems for patients. This new research makes clear that such claims greatly understate the risk of opioid abuse and addiction.

The researchers divided the 148 studies into four general categories based on how the studies defined problematic opioid use:

1. Dependence and opioid use disorder: 43 studies that identified problematic opioid use through diagnostic codes (formal diagnoses with precise definitions);
2. Signs and symptoms of dependence and opioid use disorder: 44 studies that looked for behaviors indicative of dependence and opioid use disorder, such as craving, tolerance, or withdrawal, without using specific diagnostic codes;
3. aberrant behavior: 76 studies examined inappropriate or worrying behavior, such as early requests for refills, repeated dose increases, or frequently lost prescriptions; and
4. at risk of dependence or opioid use disorder: 8 studies that looked for characteristics that might increase the risk of developing opioid dependence or opioid use disorder in the future; but the characteristics did not fall into the previous categories of deviant behavior or dependence or opioid use disorder.

Some studies reported multiple outcomes in the same participants using different measurement criteria, so the total number of studies in each category is more than 148. The prevalence (frequency) of problematic opioid use for each category was:

1. Dependence and opioid use disorder: 9.3% or almost 1 in 10 patients.
2. Signs and symptoms of dependence and opioid use disorder: 29.6%, almost 1 in 3 patients.
3. Deviant behavior: 22%, more than 1 in 5 patients.
4. Risk of dependence or opioid use disorder: 12.4%, or almost 1 in 8 patients.

Clinicians and policy makers need a more accurate estimate of the prevalence of problematic opioid use among patients with pain so they can assess the true extent of the problem, change prescribing policies when necessary, and develop and implement effective interventions to combat the problem. Knowing the extent of the problem is a necessary step to getting it under control.”

Kyla Thomas, Main author, Professor of Public Health Medicine, University of Bristol

The studies in this review are predominantly from North American research areas and high-income countries. One hundred and six of the 148 studies were conducted between 2010 and 2021; the oldest study dates from 1985. Study size varied between 15 and 2,304,181 patients. Due to the high heterogeneity of the studies, these results should be interpreted with caution.