Clinical Science
Cross-Country Differences in Pain Medication Before and After Spinal Cord Stimulation: A Pooled Analysis of Individual Patient Data From Two Prospective Studies in the United Kingdom and Belgium

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Abstract

Objectives

Spinal cord stimulation (SCS) can reduce the need for opioids; however, the influence on the full spectrum of pain medication is less known. The aims of this study were to explore general prescription practices for patients scheduled for SCS, potential differences in prescriptions between Belgium and United Kingdom, and the influence of SCS on pain medication.

Materials and Methods

Individual patient data from the TRIAL-STIM study in the United Kingdom and DISCOVER in Belgium were pooled. Medication use was collected before SCS and three months after SCS from 180 chronic pain patients. The Medication Quantification Scale III (MQS) was used to calculate a total score for medication use, as well as subscores for several classes. Differences in prescription practices between United Kingdom and Belgium were evaluated with two-sided Wilcoxon tests. To evaluate differences in medication use after three months of SCS between United Kingdom and Belgium, Tweedie-generalized linear models were calculated.

Results

There was a statistically significant difference (−6.40 [95% CI from −3.40 to −9.10]) between the median total MQS score in United Kingdom and Belgium before SCS. Additionally, a significant difference was found for nonsteroidal anti-inflammatory drugs (NSAIDs) (−3.40 [95% CI −3.40 to −6.80]), neuropathic agents (−2.30 [95% CI −0.40 to −3.80]), and benzodiazepines (1.83e−05 [95% CI 2.64−05 to 7.45−05]) between United Kingdom and Belgium, before SCS. Tweedie-generalized models revealed a statistically significant interaction between country and time for MQS, neuropathic agents, and opioids.

Conclusions

Our combined analysis revealed differences in prescription practice in patients scheduled for SCS implantation between Belgium and United Kingdom. NSAIDs and neuropathic mood agents are more frequently used in the United Kingdom, presumably due to easier access to repeat prescriptions and over the counter medications. After three months of SCS, a decrease in medication use is observed in both countries, with higher reductions in Belgium, presumably due to strict regulations concerning reimbursement criteria.

Introduction

Pain and pain-related conditions are recognized as prominent causes of disability worldwide by the Global Burden of Disease Studies.1, 2, 3 Chronic pain is estimated to affect approximately 37% of the population in Belgium4 and 43% in the United Kingdom5 and has a large impact on the economies of every country worldwide. The cost of back pain alone has been estimated at around one-fifth of the total healthcare expenditure in a country or 1.5% of the annual gross domestic product.6 The costs of analgesic medication prescription and pain-related primary care appointments for the management of chronic pain in the United Kingdom have been estimated at approximately £580 million per year,7 while annual costs associated with loss of productivity due to chronic pain have been reported to total £11 billion.8

The pharmaceutical management of pain commonly follows the steps on the World Health Organization (WHO) analgesic ladder.9 The WHO ladder was initially developed for the treatment of cancer pain, but it is applicable to most pain conditions, among which chronic pain management. In brief, step 1 consists of nonopioid analgesics, such as paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDs). If the pain persists or increases, weak opioids such as codeine would be provided for mild-to-moderate pain (ie, step 2) followed by strong opioids (eg, morphine) for moderate-to-severe pain (ie, step 3). Paracetamol and some NSAIDs can be obtained over the counter (ie, without a prescription) in the United Kingdom, but in Belgium, a prescription is required. Opioids are only available upon receipt of a prescription, except for small doses of weak opioids such as codeine with paracetamol (8/500), which are accessible over the counter in the United Kingdom.10

Spinal cord stimulation (SCS) has been shown to be an effective and cost-effective intervention for the management of chronic pain with neuropathic features.11, 12, 13, 14 Reduction or cessation in the use of opioids following SCS has been reported in several studies.15,16 However, there has been limited research on the role of SCS in facilitating reductions in the use of pharmaceutical therapies in addition to opioids.

The aims of this study are to investigate the use of pharmaceutical agents commonly employed for the management of chronic pain following SCS, explore potential differences in prescription practices between Belgium and UK settings and factors that may affect the use of oral analgesics after implantation of the SCS device.

Section snippets

Study Design

For this study, individual patient data from two prospective, multicenter studies were used; namely the TRIAL-STIM study (ISRCTN, ISRCTN60778781)17 and DISCOVER study (Clinicaltrials.gov NCT02787265).18 The TRIAL-STIM study was approved by the UK Health Research Authority North East Research Ethics Committee (17/NE/0056). The DISCOVER study protocol was approved by the ethics committee of Universitair Ziekenhuis Brussel (B.U.N. 143201629180). In both studies, written informed consent was

Results

In total, data of 180 patients were analyzed in this study (99 females, 81 males). Baseline characteristics of the patients from the TRIAL-STIM study and DISCOVER study are presented in Table 1.

Discussion

For more than a decade, physicians have been confronted with the negative long-term impact of opioids in terms of analgesic tolerance, hyperalgesia, or drug dependence.22 Additionally, the use of other types of pain medication is not without risk either since misuse and dependency problems with benzodiazepines or gabapentinoids have been reported.23,24 Awareness has increased of the risk of gastrointestinal and cardiac adverse events caused by NSAIDs use in the chronic pain setting.25 Moreover,

Conclusions

Our combined analysis revealed differences in prescription practices between Belgium and the United Kingdom, in patients scheduled for SCS implantation. More specifically, NSAIDs and neuropathic mood agents are more frequently used in the United Kingdom compared to Belgium, while the reverse is observed for benzodiazepines. A possible explanation for the increased use of NSAIDs in the United Kingdom can be found in the “self-care strategy” with direct access to this type of medication without

Authorship Statements

Lisa Goudman, Rui V. Duarte, Sam Eldabe, and Maarten Moens were responsible for the conceptualization of the study. All authors were responsible for the data collection, formal analysis, methodology and writing, and reviewing and editing of the manuscript. All authors approved the final version of the manuscript.

References (38)

  • Global burden of 369 diseases and injuries in 204 countries and territories, 1990-2019: a systematic analysis for the Global Burden of Disease Study 2019

    Lancet

    (2020)
  • A. Fayaz et al.

    Prevalence of chronic pain in the UK: a systematic review and meta-analysis of population studies

    BMJ Open

    (2016)
  • C.J. Phillips

    Economic burden of chronic pain

    Expert Rev Pharmacoecon Outcomes Res

    (2006)
  • NHS digital. Prescription cost analysis—England, 2017 [PAS]. 2017....
  • V. Ventafridda et al.

    WHO guidelines for the use of analgesics in cancer pain

    Int J Tissue React

    (1985)
  • National Health Service. Co-codamol for adults. 2020. https://www.nhs.uk/medicines/co-codamol-adults/. Accessed April...
  • M.A. Kemler et al.

    Spinal cord stimulation in patients with chronic reflex sympathetic dystrophy

    N Engl J Med

    (2000)
  • R.B. North et al.

    Spinal cord stimulation versus repeated lumbosacral spine surgery for chronic pain: a randomized, controlled trial

    Neurosurgery

    (2005)
  • A. Al-Kaisy et al.

    10 kHz SCS therapy for chronic pain, effects on opioid usage: post hoc analysis of data from two prospective studies

    Sci Rep

    (2019)
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    Source(s) of financial support: The TRIAL-STIM study was funded by the National Institute for Health Research (NIHR) Research for Patient Benefit (RfPB) program (project number: PB-PG-0815-20028). DISCOVER was funded by Medtronic Europe SARL that provided a research grant.

    Conflict of Interest: Rui V. Duarte has received consultancy fees from Medtronic Ltd, Boston Scientific Corp, Mainstay Medical, and Saluda Medical. Sam Eldabe has received consultancy fees from Medtronic Ltd, Mainstay Medical, Boston Scientific Corp, and Abbott. His department received research funding from the National Institute of Health Research, Medtronic Ltd, and Nevro Corp. Maarten Moens has received speaker fees from Medtronic and Nevro. STIMULUS received independent research grants from Medtronic. The remaining authors have no conflicts of interest to report.

    a

    These authors contributed equally to this study.

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