Chronic pain
Pain is defined by the International Association of the Study of Pain (IASP) as an unpleasant sensory and emotional experience associated with actual or potential tissue damage.1 Under the latest World Health Organization (WHO) International Classification of Diseases, Eleventh edition, chronic pain is classified as either chronic primary pain or chronic secondary pain.2 Chronic primary pain is defined as pain that persists or recurs for longer than 3 months and is associated with significant emotional distress or functional disability and that cannot be better accounted for by another chronic pain condition. Chronic secondary pain syndromes are linked to other diseases as the underlying cause, for which pain may initially be regarded as a symptom.
Pain has a significant impact globally, with the Global Burden of Disease study 2016 finding pain and pain-related diseases to be a leading cause of disability and disease burden.3 Estimates of the prevalence of chronic pain vary in the literature but experiences of chronic pain, a complex and distressing condition, are common. A systematic review of UK studies estimated a pooled prevalence of chronic pain of 43.5% and prevalence of moderate-severely disabling chronic pain between 10.4% and 14.3%.4 More recent estimates, drawn from electronic health records (2016–7), suggest that 31.9% of adults with musculoskeletal disorders in England experience ‘high impact’ chronic pain.5
Chronic pain can have a significant impact on peoples’ lives and more broadly on society. People who are permanently unable to work because of long-term sickness or disability are more likely to report having chronic pain and people who report chronic pain are less likely to be in employment.6 Chronic pain does not affect people equally. Women report a higher prevalence than men and people living in more deprived areas of England are more likely to report having chronic pain than those living in the least deprived areas.6 Black people are more likely to experience chronic pain than people of other ethnicities.6
Opioid therapy for chronic non-cancer pain
Opioid therapy has been the mainstay of pain management for centuries. Although only a small dose may be required initially to manage someone’s pain, the nervous system rapidly develops tolerance to the effects of opioids,7 including the analgesic effect, which means that the opioid dose needs to be increased over time to achieve the same level of pain relief. Some people may experience hypersensitivity to pain because of long-term opioid use.8
The use of opioids in acute and end-of-life pain is well established, but evidence does not support the clinical effectiveness of longer-term (particularly high-dose) opioid treatment for chronic pain.9 Furthermore, treatment carries a dose-dependent risk for serious harms, which increase substantially at doses above an oral morphine equivalent of 120 mg/day.10 The long-term use of opioid therapy for the management of non-cancer pain has therefore been questioned, and in 2018, IASP published a statement recommending caution against continuous, longer-term use of opioids because of issues with efficacy and safety.11
There has also been increasing recognition in the USA, Canada, Australia and many European countries (including the UK) that efforts to improve pain management have led to continuous increases in opioid prescribing.12–14 In England, opioid prescriptions were found to have increased by 34% between 1998 and 2016.13 A UK-wide study found evidence of wide variation in prescribing practices, with older age groups and social deprivation associated with an incremental increase in long-term opioid use.15 An alarming rise in the number of deaths associated with the use of prescription opioids in the USA and Canada,16 have renewed global calls for the reduction of new prescriptions of opioids and high-dose prescribing.
Recent international guidelines place a greater emphasis on treating chronic non-cancer pain with non-pharmacological therapies. For example, Almeida et al.17 examined changes in the management recommendations for low back pain in national clinical practice guidelines from the UK, Denmark, Belgium and the USA, finding that non-pharmacological treatments were now more consistently encouraged over pharmacological treatments. New National Institute for Health and Care Excellence (NICE) guidelines for chronic primary pain published in 2021 recommend that patients be offered psychological therapies, acupuncture or group-based exercise.18
Tapering and stopping opioid therapies
The National Patient Safety Team’s Medicines Safety Improvement Programme (MedSIP) has recognised the harms of high-dose opioid prescribing (> 120 mg oral morphine equivalent) and set ambitions to reduce this practice by 50% by March 2024.19 The Faculty of Pain Management ‘Opioids Aware’ prescribing resource20 provides indications for the gradual reduction (tapering) of opioids and/or discontinuation (summarised in Box 1).
It is important to taper or stop the opioid regimen if:
- The medication is not providing useful pain relief. The dose above which harms outweigh benefits is 120 mg oral morphine equivalent/24 hours. Increasing opioid load above this dose is unlikely to yield further benefits but exposes the patient to increased harm.
- The underlying painful condition resolves.
- The patient receives a definitive pain-relieving intervention (e.g. joint replacement).
- The patient develops intolerable side effects.
- There is strong evidence that the patient is diverting his/her medications to others.
Systematic reviews that have examined the effectiveness of interventions aimed at reducing opioid prescribing have however been limited by the low quality of the evidence available.21–23 Very little published research has been conducted in the UK to date. At the end of 2021, the 15 Patient Safety Collaboratives (PSC) in England carried out an intelligence gathering exercise on behalf of the MedSIP.24 This exercise identified 112 examples of service activities across England that were being provided with the specific aim of reducing the prescribing of opioids. The pathway that emerged from their analysis covered five stages for tapering and stopping opioids:
- prevent initiation, strategies and practices that divert treatment away from the prescribing of opioids while still effectively managing pain
- de-escalate, activity that prevents increasing doses of opioids or minimises the duration of treatment
- find chronic use, methods used to identify patients who are at risk of dependence or harm from continuing opioid use
- treat (taper and support), interventions aimed at reducing opioid prescribing
- sustain, interventions designed to maintain the lowest possible opioid use.
The Medicines Optimisation Group at the University of East Anglia drew on this local and national evidence to develop a toolkit for opioid tapering. They identified seven key features that should be included in all opioid-tapering interventions (shown in Box 2).
- There needs to be a clear expectation that opioid deprescribing is the responsibility of prescribers. …and programmes should incorporate…
- Information about the consequences of excess opioid use.
- Information about how to taper (guidelines).
- Prescribers with appropriate knowledge and skills to initiate tapering discussions and navigate the patient pathway.
- A consistent approach by all members of the healthcare team.
- Comprehensive education for patients.
- A pathway for patient management including access to appropriate levels of psychological and physical support.
Only limited attention has been given in systematic reviews to the consideration of adverse events (AEs). Further, the conflict between the physician’s desire to relieve the patient’s pain and fear of inducing addiction persists and can influence the selection of therapies including opioids. By exploring barriers and facilitators to, the safe and effective reduced use of prescribed opioids for chronic non-cancer pain, we can more easily identify strategies that will support patients, carers and healthcare professionals to safely and effectively taper opioids, where appropriate. Furthermore, analysis of barriers and facilitators can contribute to an improved understanding of how multiple levels of the healthcare system (i.e. individual, interpersonal, organisational and environmental factors) may influence ‘transformation and change processes’ (Williamson and Nelson, 2017, p. 1249)25 to hinder or enable an opioid taper. One recent systematic review explored barriers and facilitators in the broader context of opioid deprescribing and monitoring;26 however, no systematic reviews were located focusing specifically on factors impacting on the success of opioid tapering.
The target populations for opioid-tapering interventions are likely to be heterogeneous with different sociodemographic characteristics, which may affect their response to opioid-tapering interventions. Consequently, this may result in a widening of social and health inequalities. However, little is known about opioid-tapering interventions and their impact on inequalities. Furthermore, more opioids are prescribed in the north than in the south of England and more opioids are prescribed in areas of greater social deprivation.13,27 It is therefore paramount to consider and evaluate potential inequalities in access to interventions that aim to reduce the use of opioids. To date, no systematic reviews have focused on inequalities in effectiveness or patient experience for different groups of people accessing or undergoing opioid tapering.