One in ten people with chronic pain could experience opioid dependence, suggest study results

Almost one in ten of people with chronic, non-cancer-related pain who take prescription opioid painkillers experience opioid dependence or opioid use disorder, results from a review and meta-analysis have indicated.

The review, published in Addiction on 7 August 2024, looked at data from 148 studies involving more than 4.3 million adults with chronic pain between 1985 and 2021, predominantly from North America and other high-income countries, including the UK.

The authors included studies if they reported problematic pharmaceutical opioid use (‘POU’) and defined four categories of POU: dependence and opioid use disorder (‘DOUD’) identified using diagnostic codes; signs and symptoms of DOUD; aberrant behaviour; and at risk of DOUD.

Researchers found the pooled prevalence of DOUD was 9.3%, with 43 of the 148 studies reporting DOUD identified using diagnostic codes (n=2,691,475).

Almost one-third of patients (29.6%) were found to have shown ‘signs and symptoms of DOUD’, which were reported in 44 studies (n=58,479).

More than one-fifth of patients (22%) showed ‘aberrant behaviour’ in 79 studies (n=1,180,289) — such as seeking early refills, repeated dose escalations or frequently lost prescriptions, while more than one in ten patients (12%) were found to be at-risk of DOUD in eight studies (n=26,876) owing to exhibiting characteristics which may increase their risk of developing DOUD in the future.

However, the authors note: “Due to the high heterogeneity of the studies, these findings should be interpreted with caution.

“A single study contributed to 54% of the entire sample. Few studies were reported from lower- and middle-income countries, with no data available from Africa, South America or the Caribbean,” the authors said.

The authors say that previous studies have found a large variation in reported prevalence rates of problematic POU.

“A major limitation is the inconsistency in defining POU with the use of multiple definitions and terminology,” including the “small number of studies included in reviews and the lack of robustness of data aggregation using disparate and inconsistent POU definitions”, the paper said.

“However, despite the problems identified with the literature, there is enough evidence describing the extent of the problem for clinicians and policymakers to take appropriate action.

“Better approaches are urgently needed to prevent and manage POU in chronic non-cancer pain,” the paper added.

Roger Knaggs, professor of pain management at the University of Nottingham School of Pharmacy and president of the British Pain Society, told The Pharmaceutical Journal: “Only a small proportion of studies (5 out of 148) included were from the UK, so these prevalence figures may not be directly applicable to our country.

“However, problematic use is seen by health professionals in all settings: community, primary care, and secondary care,” he said.

“There is a need for a balanced approach. Opioids are effective for acute pain, often associated with trauma or after surgery, and for pain at the end of life. However, the evidence for many chronic non-cancer pains is modest for short periods — up to three months — and much more limited for longer periods. In addition, there is an increasing appreciation of numerous harms, including problematic use.

“Opioids should not be stopped abruptly or tapering enforced on an individual. In most circumstances tapering or deprescribing should be individualised in a person-centred approach. This is highlighted in several national guidelines and policy initiatives. There is an increasing evidence base to support effective and safe opioid tapering, including two large NIHR-funded studies, I-WOTCH and PROMPPT.”

In May 2024, NHS Fife launched a pharmacist-led initiative to reduce unnecessary prescribing of high-risk pain medicines, including opioids, for chronic pain.

Writing for The Pharmaceutical Journal in July 2023, pharmacist Rachel Berry described how the North East and North Cumbria Integrated Care Board’s #painkillersdontexist campaign was developed to highlight the risks of long-term pain medication.