Patient engagement in designing, conducting, and disseminating clinical pain research: IMMPACT recommended considerations

ABSTRACT

In the traditional clinical research model, patients are typically involved only as participants. However, there has been a shift in recent years highlighting the value and contributions that patients bring as members of the research team, across the clinical research lifecycle. It is becoming increasingly evident that to develop research that is both meaningful to people who have the targeted condition and is feasible, there are important benefits of involving patients in the planning, conduct, and dissemination of research from its earliest stages. In fact, research funders and regulatory agencies are now explicitly encouraging, and sometimes requiring, that patients are engaged as partners in research. Although this approach has become commonplace in some fields of clinical research, it remains the exception in clinical pain research. As such, the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials convened a meeting with patient partners and international representatives from academia, patient advocacy groups, government regulatory agencies, research funding organizations, academic journals, and the biopharmaceutical industry to develop consensus recommendations for advancing patient engagement in all stages of clinical pain research in an effective and purposeful manner. This article summarizes the results of this meeting and offers considerations for meaningful and authentic engagement of patient partners in clinical pain research, including recommendations for representation, timing, continuous engagement, measurement, reporting, and research dissemination.

Impact of American Diabetes Association 2022 Guidelines on Prescribing Rates of Sodium-Glucose Cotransporter-2 Inhibitors in Ambulatory Care Organization Patients With Type 2 Diabetes

Background: Recent clinical trials and guideline updates have highlighted the efficacy and safety of sodium-glucose cotransporter-2 inhibitor (SGLT2i) use in patients with type 2 diabetes (T2D) and comorbidities including atherosclerotic cardiovascular disease (ASCVD), chronic kidney disease (CKD), or heart failure (HF). Objective: This study assesses the rates of guideline-based prescribing of SGLT2i in patients with T2D and one or more of the following comorbidities: ASCVD, CKD, or HF, prior to and after the 2022 American Diabetes Association (ADA) guideline publication within the Atrius Health clinical pharmacy, internal medicine, and specialty medicine departments. Methods: This is a retrospective chart review of data from the electronic medical record. Patients with the aforementioned criteria were included if they were managed by either the clinical pharmacy department, internal medicine, or specialty medicine departments. Patients were excluded if they did not have any of the comorbidities listed or a form of diabetes other than T2D. Results: Of the 10,631 patients enrolled, 354 (3.3%) were initiated on an SGLT2i during the study. The average number of SGLT2i initiations prior to the 2022 ADA guideline publication was five prescription starts per week. After the guideline publication initiation increased to seven prescription starts per week. Secondary outcomes showed the majority of SGLT2i prescriptions were started in the internal medicine department, followed by cardiology and nephrology. Conclusion: Overall utilization rates of SGLT2i are low but increased after the 2022 ADA guidelines were published. These results suggest opportunities to optimize the use of SGLT2i in this patient population.

Research objectives and general considerations for pragmatic clinical trials of pain treatments: IMMPACT statement

ABSTRACT

Many questions regarding the clinical management of people experiencing pain and related health policy decision-making may best be answered by pragmatic controlled trials. To generate clinically relevant and widely applicable findings, such trials aim to reproduce elements of routine clinical care or are embedded within clinical workflows. In contrast with traditional efficacy trials, pragmatic trials are intended to address a broader set of external validity questions critical for stakeholders (clinicians, healthcare leaders, policymakers, insurers, and patients) in considering the adoption and use of evidence-based treatments in daily clinical care. This article summarizes methodological considerations for pragmatic trials, mainly concerning methods of fundamental importance to the internal validity of trials. The relationship between these methods and common pragmatic trials methods and goals is considered, recognizing that the resulting trial designs are highly dependent on the specific research question under investigation. The basis of this statement was an Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) systematic review of methods and a consensus meeting. The meeting was organized by the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) public-private partnership. The consensus process was informed by expert presentations, panel and consensus discussions, and a preparatory systematic review. In the context of pragmatic trials of pain treatments, we present fundamental considerations for the planning phase of pragmatic trials, including the specification of trial objectives, the selection of adequate designs, and methods to enhance internal validity while maintaining the ability to answer pragmatic research questions.

Perspectives on Participation in Clinical Trials Among Individuals With Pain, Depression, and/or Anxiety: An ACTTION Scoping Review

For individuals experiencing pain, the decision to engage in clinical trials may be influenced by a number of factors including current and past care, illness severity, physical functioning, financial stress, and caregiver support. Co-occurring depression and anxiety may add to these challenges. The aim of this scoping review was to describe perspectives about clinical trial participation, including recruitment and retention among individuals with pain and pain comorbidities, including depression and/or anxiety. We searched PubMed, CINAHL, PsycINFO, and Cochrane CENTRAL databases. Study features, sample demographics, perspectives, barriers and/or motivations were collected and described. A total of 35 assessments were included in this scoping review with 24 focused on individuals with pain (24/35, 68.6%), 9 on individuals with depression and/or anxiety (9/35, 25.7%), and 2 on individuals with pain and co-occurring depression/anxiety (2/35, 5.7%). Barriers among participants with pain and those with depression included: research team's communication of information, fear of interventional risks, distrust (only among respondents with pain), too many procedures, fear of inadequate treatment, disease-life stressors, and embarrassment with study procedures (more commonly reported in participants with depression). Facilitators in both groups included: altruism and supportive staff, better access to care, and the ability to have outcome feedback (more commonly among individuals with depression). Individuals with pain and depression experience challenges that affect trial recruitment and retention. Engaging individuals with pain within research planning may assist in addressing these barriers and the needs of individuals affected by pain and/or depression. PERSPECTIVE: This review highlights the need to address barriers and facilitators to participation in clinical trials, including the need for an assessment of perspectives from underserved or marginalized populations.

A comparison of registered and published primary outcomes in clinical trials of opioid use disorder: ACTTION review and recommendations

BACKGROUND AND AIMS

Prospective trial registration can increase research integrity. This Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) review was designed to compare the primary outcomes (PO) reported in registries with associated publications for opioid use disorder (OUD) clinical trials.

DESIGN

The World Health Organization's International Clinical Trials Registry Platform (ICTRP) was searched for completed trials (2010 through 2019). Associated publications were identified and paired with trial registry data based on the publication date.

MEASUREMENTS

Reviewers independently rated the occurrence of discrepancies between the POs in the registry compared to the publication. An analysis of prospective versus retrospective registration was also completed.

FINDINGS

One-hundred and forty trials were identified in the search, and 43 registry-publication pairs evaluated. Only 34 of the 43 pairs could be examined for discrepancies because nine did not report a PO in registry and publication. Of the 34 pairs, only four met rigorous criteria for prospective trial registration and had an exact match of POs. In contrast, the majority of the 34 trials, or 80%, had inconsistent POs (e.g., registered secondary outcomes published as primary; the timing of PO not specified) and/or were retrospectively registered.

CONCLUSIONS

Many clinical trials focused on OUD have not met the standards of trial registration, such as consistent reporting of POs and prospective registration. Failure to properly register trial characteristics undermines the validity of research findings and can delay the development of life-saving treatments. Recommendations for improving prospective trial reporting practices are provided.

The prevalence of comorbid chronic pain conditions among patients with temporomandibular disorders: A systematic review

BACKGROUND

This systematic review was designed to evaluate the presence of comorbid conditions among patients with temporomandibular disorders (TMDs).

TYPES OF STUDIES REVIEWED

The authors reviewed studies that reported the prevalence or incidence of chronic pain conditions or psychiatric disorders (anxiety, mood, personality disorders) among patients with any type of TMD. The authors calculated sample size-weighted prevalence estimates when data were reported in 2 or more studies for the same comorbid condition.

RESULTS

A total of 9 prevalence studies and no incidence studies were eligible for review; 8 of the studies examined chronic pain comorbidities. Weighted estimates showed high prevalence of pain comorbidities across studies, including current chronic back pain (66%), myofascial syndrome (50%), chronic stomach pain (50%), chronic migraine headache (40%), irritable bowel syndrome (19%), and fibromyalgia (14%). A single study examined psychiatric disorders and found that current depression was the most prevalent disorder identified (17.5%).

CONCLUSIONS AND PRACTICAL IMPLICATIONS

There is a high prevalence of comorbid chronic pain conditions among patients with TMDs, with more than 50% of patients reporting chronic back pain, myofascial syndrome, and chronic stomach pain. Psychiatric disorders among patients with different types of TMDs were studied less commonly in this pain population. Knowledge of the distribution of these and other comorbid disease conditions among patients with different types of TMDs can help dentists and other health care providers to identify personalized treatment strategies, including the coordination of care across medical specialties.

Pragmatic trials of pain therapies: a systematic review of methods

ABSTRACT

Pragmatic randomised clinical trials aim to directly inform clinical or health policy decision making. Here, we systematically review methods and design of pragmatic trials of pain therapies to examine methods, identify common challenges, and areas for improvement. Seven databases were searched for pragmatic randomised controlled clinical trials that assessed pain treatment in a clinical population of adults reporting pain. All screening steps and data extractions were performed twice. Data were synthesised descriptively, and correlation analyses between prespecified trial features and PRECIS-2 (PRagmatic-Explanatory Continuum Indicator Summary 2) ratings and attrition were performed. Protocol registration: PROSPERO-ID CRD42020178954. Of 57 included trials, only 21% assessed pharmacological interventions, the remainder physical, surgical, psychological, or self-management pain therapies. Three-quarters of the trials were comparative effectiveness designs, often conducted in multiple centres (median: 5; Q1/3: 1, 9.25) and with a median sample size of 234 patients at randomization (Q1/3: 135.5; 363.5). Although most trials recruited patients with chronic pain, reporting of pain duration was poor and not well described. Reporting was comprehensive for most general items, while often deficient for specific pragmatic aspects. Average ratings for pragmatism were highest for treatment adherence flexibility and clinical relevance of outcome measures. They were lowest for patient recruitment methods and extent of follow-up measurements and appointments. Current practice in pragmatic trials of pain treatments can be improved in areas such as patient recruitment and reporting of methods, analysis, and interpretation of data. These improvements will facilitate translatability to other real-world settings-the purpose of pragmatic trials.

Risk factors for persistent pain after breast and thoracic surgeries: a systematic literature review and meta-analysis

ABSTRACT

Persistent postsurgical pain (PPSP) is common after breast and thoracic surgeries. Understanding which risk factors consistently contribute to PPSP will allow clinicians to apply preventive strategies, as they emerge, to high-risk patients. The objective of this work was to systematically review and meta-analyze the literature on risk factors of PPSP after breast and thoracic surgeries. A systematic literature search using Ovid Medline, Cochrane Central Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature, Embase, PsycINFO, and Scopus databases was conducted. Study screening with inclusion and exclusion criteria, data extraction, and risk of bias assessment was performed independently by 2 authors. The data for each surgical group were analyzed separately and meta-analyzed where possible. The literature search yielded 5584 articles, and data from 126 breast surgery and 143 thoracic surgery articles were considered for meta-analysis. In breast surgery, younger age, higher body mass index, anxiety, depression, diabetes, smoking, preoperative pain, moderate to severe acute postoperative pain, reoperation, radiotherapy, and axillary lymph node dissection were the main factors associated with higher risk of PPSP. In thoracic surgery, younger age, female sex, hypertension, preoperative pain, moderate to severe acute postoperative pain, surgical approach, major procedure, and wound complications were associated with PPSP. This systematic review demonstrated certain consistent risk factors of PPSP after breast and thoracic surgeries, as well as identified research gaps. Understanding the factors that increase susceptibility to PPSP can help selectively allocate resources to optimize perioperative care in high-risk patients and help develop targeted, risk-stratified interventions for PPSP prevention.

Research approaches for evaluating opioid sparing in clinical trials of acute and chronic pain treatments: Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials recommendations

ABSTRACT

Randomized clinical trials have demonstrated the efficacy of opioid analgesics for the treatment of acute and chronic pain conditions, and for some patients, these medications may be the only effective treatment available. Unfortunately, opioid analgesics are also associated with major risks (eg, opioid use disorder) and adverse outcomes (eg, respiratory depression and falls). The risks and adverse outcomes associated with opioid analgesics have prompted efforts to reduce their use in the treatment of both acute and chronic pain. This article presents Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) consensus recommendations for the design of opioid-sparing clinical trials. The recommendations presented in this article are based on the following definition of an opioid-sparing intervention: any intervention that (1) prevents the initiation of treatment with opioid analgesics, (2) decreases the duration of such treatment, (3) reduces the total dosages of opioids that are prescribed for or used by patients, or (4) reduces opioid-related adverse outcomes (without increasing opioid dosages), all without causing an unacceptable increase in pain. These recommendations are based on the results of a background review, presentations and discussions at an IMMPACT consensus meeting, and iterative drafts of this article modified to accommodate input from the co-authors. We discuss opioid sparing definitions, study objectives, outcome measures, the assessment of opioid-related adverse events, incorporation of adequate pain control in trial design, interpretation of research findings, and future research priorities to inform opioid-sparing trial methods. The considerations and recommendations presented in this article are meant to help guide the design, conduct, analysis, and interpretation of future trials.

Research design considerations for randomized controlled trials of spinal cord stimulation for pain: Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials/Institute of Neuromodulation/International Neuromodulation Society recommendations

ABSTRACT

Spinal cord stimulation (SCS) is an interventional nonpharmacologic treatment used for chronic pain and other indications. Methods for evaluating the safety and efficacy of SCS have evolved from uncontrolled and retrospective studies to prospective randomized controlled trials (RCTs). Although randomization overcomes certain types of bias, additional challenges to the validity of RCTs of SCS include blinding, choice of control groups, nonspecific effects of treatment variables (eg, paresthesia, device programming and recharging, psychological support, and rehabilitative techniques), and safety considerations. To address these challenges, 3 professional societies (Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials, Institute of Neuromodulation, and International Neuromodulation Society) convened a meeting to develop consensus recommendations on the design, conduct, analysis, and interpretation of RCTs of SCS for chronic pain. This article summarizes the results of this meeting. Highlights of our recommendations include disclosing all funding source and potential conflicts; incorporating mechanistic objectives when possible; avoiding noninferiority designs without internal demonstration of assay sensitivity; achieving and documenting double-blinding whenever possible; documenting investigator and site experience; keeping all information provided to patients balanced with respect to expectation of benefit; disclosing all information provided to patients, including verbal scripts; using placebo/sham controls when possible; capturing a complete set of outcome assessments; accounting for ancillary pharmacologic and nonpharmacologic treatments in a clear manner; providing a complete description of intended and actual programming interactions; making a prospective ascertainment of SCS-specific safety outcomes; training patients and researchers on appropriate expectations, outcome assessments, and other key aspects of study performance; and providing transparent and complete reporting of results according to applicable reporting guidelines.

The Prevalence of Psychiatric and Chronic Pain Comorbidities in Fibromyalgia: an ACTTION systematic review

Fibromyalgia (FM) is a chronic widespread pain condition that overlaps with multiple comorbid health conditions and contributes to considerable patient distress. The aim of this review was to provide a systematic overview of psychiatric and chronic pain comorbidities among patients diagnosed with FM and to inform the development of recommendations for the design of clinical trials. Thirty-one, cross-sectional, clinical epidemiology studies that evaluated patients diagnosed with FM were included for review. None of the reviewed studies reported on the incidence of these comorbidities. Sample size-weighted prevalence estimates were calculated when prevalence data were reported in 2 or more studies for the same comorbid condition. The most prevalent comorbidity across all studies reviewed was depression/major depressive disorder (MDD) with over half of the patients included having this diagnosis in their lifetime (weighted prevalence up to 63%). In addition, nearly one-third of FM patients examined had current or lifetime bipolar disorder, panic disorder, or post-traumatic stress disorder. Less common psychiatric disorders reported included generalized anxiety disorder, obsessive compulsive disorder, and specific phobias (agoraphobia, social phobia). There were fewer studies that examined chronic pain comorbidities among FM patients, but when evaluated, prevalence was also high ranging from 39% to 76% (i.e., chronic tension-type or migraine headache, irritable bowel syndrome, myofascial pain syndrome, and temporomandibular disorders). The results of the review suggest that depression and chronic pain conditions involving head/jaw pain and IBS were elevated among FM patients compared to other conditions in the clinic-based studies. In contrast, anxiety-related disorders were much less common. Addressing the presence of these comorbid health conditions in clinical trials of treatments for FM would increase the generalizability and real-world applicability of FM research.

Systematic Review of Research Methods and Reporting Quality of Randomized Clinical Trials of Spinal Cord Stimulation for Pain

This systematic review assessed design characteristics and reporting quality of published randomized clinical trials of spinal cord stimulation (SCS) for treatment of pain in adults and adolescents. The study protocol was registered with PROSPERO (CRD42018090412). Relevant articles were identified by searching the following databases through December 31, 2018: MEDLINE, Embase, WikiStim, The Cochrane Database of Systematic Reviews, and The Cochrane Central Register of Controlled Trials. Forty-six studies were included. Eighty-seven percent of articles identified a pain-related primary outcome. Secondary outcomes included physical functioning, health-related quality of life, and reductions in opioid use. Nineteen of the 46 studies prespecified adverse events as an outcome, with 4 assessing them as a primary outcome. Eleven studies stated that they blinded participants. Of these, only 5 were assessed as being adequately blinded. The number of participants enrolled was generally low (median 38) and study durations were short (median 12 weeks), particularly in studies of angina. Fifteen studies employed an intention-to-treat analysis, of which only seven specified a method to accommodate missing data. Review of these studies identified deficiencies in both reporting and methodology. The review's findings suggest areas for improving the design of future studies and increasing transparency of reporting. PERSPECTIVE: This article presents a systematic review of research methods and reporting quality of randomized clinical trials of SCS for the treatment of various pain complaints. The review identifies deficiencies in both methodology and reporting, which may inform the design of future studies and improve reporting standards.

A Systematic Review of Economic Evaluations Reporting the Cost-Effectiveness of Spinal Cord Stimulation

OBJECTIVES

Spinal cord stimulation (SCS) is a recognized treatment for chronic pain. This systematic review aims to assess economic evaluations of SCS for the management of all chronic pain conditions, summarize key findings, and assess the quality of studies to inform healthcare resource allocation decisions and future research.

METHODS

Economic evaluations were identified by searching general medical and economic databases complemented with screening of reference lists of identified studies. No restrictions on language or treatment comparators were applied. Relevant data were extracted. The quality of included studies was assessed using the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist.

RESULTS

Fourteen studies met the inclusion criteria and were judged to be of acceptable quality. Economic evaluations assessed SCS for the management of refractory angina pectoris, failed back surgery syndrome (FBSS), complex regional pain syndrome (CRPS), diabetic peripheral neuropathy (DPN), and peripheral arterial disease. Model-based studies typically applied a 2-stage model, i.e. decision tree followed by Markov model. Time horizon varied from 1 year to lifetime. Cost-effectiveness ranged widely from dominant (SCS cost-saving and more effective) to incremental cost-effectiveness ratio of >£100,000 per quality-adjusted life-year. Cost-effectiveness appeared to depend on the time horizon, choice of comparator, and indication. Ten of the studies indicated SCS as cost-saving or cost-effective compared with the alternative strategies.

CONCLUSION

The results consistently suggest that SCS is cost-effective when considering a long-term time horizon, particularly for the management of FBSS and CRPS. Further studies are needed to assess the cost-effectiveness of SCS for ischemic pain and DPN.

Randomized Placebo-/Sham-Controlled Trials of Spinal Cord Stimulation: A Systematic Review and Methodological Appraisal

OBJECTIVES

The recent availability of paraesthesia/sensation free spinal cord stimulation (SCS) modalities allow the design of clinical trials of SCS using placebo/sham controls and blinding of patients, clinicians, and researchers. The aims of this study were to: 1) systematically review the current evidence base of randomized controlled trials (RCTs) of SCS placebo/sham trials and 2) to undertake a methodological critique of their methods. Based on this critique, we developed a checklist for the design and reporting of future RCTs of SCS.

MATERIALS AND METHODS

Electronic data bases were searched from inception until January 2019 for RCTs of SCS using a placebo/sham control. RCTs with only an active comparator arm were excluded. The results are presented as a narrative synthesis.

RESULTS

Searches identified 12 eligible RCTs. SCS modalities included paraesthesia stimulation, subthreshold, burst, and high-frequency SCS and were mainly conducted in patients with failed back surgery syndrome, complex regional pain syndrome, and refractory angina. The quality and transparency of reporting of the methods of placebo stimulation, blinding of patients, clinicians, and researchers varied markedly across studies.

CONCLUSIONS

To date the methods of placebo/sham control and blinding in RCTs have been poorly reported, leading to concerns about the validity and replicability of the findings. Important aspects that need to be clearly reported in the design of placebo-/sham-controlled RCTs of SCS include the transparent reporting of stimulation programming parameters, patient position during perception threshold measurement, management of the patient handheld programmer, frequency of recharging, and assessment of the fidelity of blinding.

Study of η and η' Photoproduction at MAMI

The reactions γp→ηp and γp→η^{'}p are measured from their thresholds up to the center-of-mass energy W=1.96  GeV with the tagged-photon facilities at the Mainz Microtron, MAMI. Differential cross sections are obtained with unprecedented statistical accuracy, providing fine energy binning and full production-angle coverage. A strong cusp is observed in the total cross section for η photoproduction at the energies in the vicinity of the η^{'} threshold, W=1896  MeV (E_{γ}=1447  MeV). Within the framework of a revised ηMAID isobar model, the cusp, in connection with a steep rise of the η^{'} total cross section from its threshold, can only be explained by a strong coupling of the poorly known N(1895)1/2^{-} state to both ηp and η^{'}p. Including the new high-accuracy results in the ηMAID fit to available η and η^{'} photoproduction data allows the determination of the N(1895)1/2^{-} properties.

Pharmacotherapy for neuropathic pain in adults: a systematic review and meta-analysis

BACKGROUND

New drug treatments, clinical trials, and standards of quality for assessment of evidence justify an update of evidence-based recommendations for the pharmacological treatment of neuropathic pain. Using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE), we revised the Special Interest Group on Neuropathic Pain (NeuPSIG) recommendations for the pharmacotherapy of neuropathic pain based on the results of a systematic review and meta-analysis.

METHODS

Between April, 2013, and January, 2014, NeuPSIG of the International Association for the Study of Pain did a systematic review and meta-analysis of randomised, double-blind studies of oral and topical pharmacotherapy for neuropathic pain, including studies published in peer-reviewed journals since January, 1966, and unpublished trials retrieved from ClinicalTrials.gov and websites of pharmaceutical companies. We used number needed to treat (NNT) for 50% pain relief as a primary measure and assessed publication bias; NNT was calculated with the fixed-effects Mantel-Haenszel method.

FINDINGS

229 studies were included in the meta-analysis. Analysis of publication bias suggested a 10% overstatement of treatment effects. Studies published in peer-reviewed journals reported greater effects than did unpublished studies (r(2) 9·3%, p=0·009). Trial outcomes were generally modest: in particular, combined NNTs were 6·4 (95% CI 5·2-8·4) for serotonin-noradrenaline reuptake inhibitors, mainly including duloxetine (nine of 14 studies); 7·7 (6·5-9·4) for pregabalin; 7·2 (5·9-9·21) for gabapentin, including gabapentin extended release and enacarbil; and 10·6 (7·4-19·0) for capsaicin high-concentration patches. NNTs were lower for tricyclic antidepressants, strong opioids, tramadol, and botulinum toxin A, and undetermined for lidocaine patches. Based on GRADE, final quality of evidence was moderate or high for all treatments apart from lidocaine patches; tolerability and safety, and values and preferences were higher for topical drugs; and cost was lower for tricyclic antidepressants and tramadol. These findings permitted a strong recommendation for use and proposal as first-line treatment in neuropathic pain for tricyclic antidepressants, serotonin-noradrenaline reuptake inhibitors, pregabalin, and gabapentin; a weak recommendation for use and proposal as second line for lidocaine patches, capsaicin high-concentration patches, and tramadol; and a weak recommendation for use and proposal as third line for strong opioids and botulinum toxin A. Topical agents and botulinum toxin A are recommended for peripheral neuropathic pain only.

INTERPRETATION

Our results support a revision of the NeuPSIG recommendations for the pharmacotherapy of neuropathic pain. Inadequate response to drug treatments constitutes a substantial unmet need in patients with neuropathic pain. Modest efficacy, large placebo responses, heterogeneous diagnostic criteria, and poor phenotypic profiling probably account for moderate trial outcomes and should be taken into account in future studies.

FUNDING

NeuPSIG of the International Association for the Study of Pain.

Opioid side effects and their treatment in patients with chronic cancer and noncancer pain

Opioids are the foundation of standard analgesic regimens for moderate to severe pain due to life-threatening illnesses such as cancer, and are increasingly employed in chronic noncancer pain of the same severity. Opioids are frequently used for long periods in these populations, sometimes for years. However, side effects are common and may reduce quality of life, or become life threatening, and frequently cause patients to discontinue opioid therapy. Successful opioid therapy dictates that benefits of analgesia outweigh safety concerns. The mechanisms, incidence, and treatment or prevention of commonly reported side effects in chronic pain populations are reviewed, employing best available evidence along with empiric practice. General management strategies include switching opioids ("opioid rotation"), discontinuation of concurrent medications that exacerbate side effects, and symptomatic treatment. In addition, recently recognized adverse events that occur after long-term opioid therapy are discussed. High-quality evidence is lacking for the treatment of most side effects, and the true incidence, underlying mechanisms, and clinical implications of long-term responses to opioid therapy are not yet fully understood.

Efficacy and safety of mu-opioid antagonists in the treatment of opioid-induced bowel dysfunction: systematic review and meta-analysis of randomized controlled trials

CONTEXT

Opioid-induced bowel dysfunction (OBD) is characterized by constipation, incomplete evacuation, bloating, and increased gastric reflux. OBD occurs both acutely and chronically, in multiple disease states, resulting in increased morbidity and reduced quality of life.

OBJECTIVE

To compare the efficacy and safety of traditional and peripherally active opioid antagonists vs conventional interventions for OBD.

DESIGN

We searched MEDLINE, the Cochrane Central Register of Controlled Trials and EMBASE. Additional reports were identified from the reference lists of retrieved articles.

STUDY SELECTION

Studies were included if they were randomized controlled trials that investigated the efficacy of mu-opioid antagonists for OBD.

DATA EXTRACTION

Data were extracted by two independent investigators and included demographic variables, diagnoses, interventions, efficacy, and adverse events.

RESULTS OF DATA SYNTHESIS

Twenty-two articles met inclusion criteria and provided data on 2,352 opioid antagonist-treated patients. The opioid antagonist investigated was alvimopan (eight studies), methylnaltrexone (six), naloxone (seven), and nalbuphine (one). Meta-analysis demonstrated that methylnaltrexone and alvimopan are efficacious in reversing opioid-induced increased gastrointestinal transit time and constipation, and that alvimopan is safe and efficacious in treating postoperative ileus. The incidence of adverse events with opioid antagonists was similar to placebo and generally reported as mild-to-moderate.

CONCLUSIONS

Insufficient evidence exists for the safety or efficacy of naloxone or nalbuphine in the treatment of OBD. Long-term efficacy and safety of any of the opioid antagonists is unknown, as is the incidence or nature of rare adverse events. Alvimopan and methylnaltrexone both show promise in treating OBD, but further data will be required to fully assess their place in therapy.

The analgesic efficacy and safety of a novel intranasal morphine formulation (morphine plus chitosan), immediate release oral morphine, intravenous morphine, and placebo in a postsurgical dental pain model

BACKGROUND

Opioids are standard treatment for postoperative pain. In this study, we compared the safety and efficacy of intranasal (i.n.) morphine to i.v. and oral morphine and placebo.

METHODS

Two-hundred-twenty-five patients with moderate-to-severe pain after third molar extraction were randomized to receive a single dose of i.n. morphine 7.5 mg or 15 mg, i.v. morphine 7.5 mg, oral morphine 60 mg or placebo. Pain intensity was assessed using visual analog and categorical scales, and pain relief using a categorical scale. Outcomes included total pain relief, pain intensity difference, summed pain intensity difference, time to analgesic onset, time to requesting rescue medication, and patients' global evaluation of their treatment. Safety assessments included adverse event recording and nasal examinations.

RESULTS

Across the various efficacy outcomes, both i.n. morphine doses were statistically similar to the positive comparators (i.v. and oral morphine), and all four morphine treatments were statistically superior to placebo. Overall, i.n. morphine 15 mg presented an efficacy profile similar to i.v. morphine 7.5 mg; both treatments demonstrated rapid onset of efficacy, generally persistent throughout the 6-h assessment period. The lower dose of i.n. morphine, 7.5 mg, was statistically similar to the other active treatments at 2 h and 6 h and similar to placebo at 4 h. Study medications were generally well tolerated, with no withdrawals due to adverse events or other safety concerns, and no serious adverse events reported. The most frequently reported adverse events were typical systemic opioid effects.

CONCLUSIONS

I.n. morphine offers a noninvasive alternative to i.v. morphine for postoperative analgesia.

Analgesic efficacy and safety of morphine-chitosan nasal solution in patients with moderate to severe pain following orthopedic surgery

INTRODUCTION

Parenteral opioids are the standard of care for treating moderate to severe postsurgical pain. This randomized, double-blind, dose-ranging study compared the safety and efficacy of intranasal (IN) morphine with intravenous (IV) morphine and placebo.

METHODS

In total, 187 postbunionectomy patients with moderate to severe pain were randomized to receive IN morphine 3.75 mg, 7.5 mg, 15 mg, or 30 mg, IV morphine 7.5 mg, or placebo in the single-dose phase and IN morphine 7.5 mg or 15 mg thereafter. The primary outcome was a dose-response assessment for total pain relief based upon visual analog scales. Secondary endpoints included pain intensity, pain relief, patient global evaluation, and time to rescue medication. Safety assessments included adverse events and nasal examination.

RESULTS

A statistically significant linear dose response was observed over the IN morphine dose range for 4-hour total pain relief. Patients reported statistically significant pain relief and pain intensity differences following IV morphine and IN morphine at doses of 7.5 mg and greater within 30 minutes postdose, compared with placebo. Median times to rescue medication were 124 and 140 minutes for IN morphine 7.5 mg and 15 mg dosage groups, respectively, and 130 minutes for IV morphine. Local adverse events associated with IN morphine were transient and mostly mild (bad taste, nasal congestion, throat irritation, and sneezing). Systemic adverse events, regardless of route of administration, were dose-related and consistent with expected opioid effects.

CONCLUSIONS

By multiple measures of pain intensity and pain relief, IN morphine provides sustained analgesia in postsurgical patients and thus may offer a safe and less invasive alternative to IV morphine.

Patient controlled opioid analgesia versus conventional opioid analgesia for postoperative pain

BACKGROUND

Patients may control postoperative pain by self-administration of intravenous opioids using devices designed for this purpose (patient controlled analgesia or PCA). A 1992 meta-analysis by Ballantyne found a strong patient preference for PCA over conventional analgesia but disclosed no differences in analgesic consumption or length of postoperative hospital stay. Although Ballantyne's meta-analysis found that PCA did have a small but statistically significant benefit upon pain intensity, Walder's review in 2001 did not find a significant differences in pain intensity and pain relief between PCA and conventionally treated groups.

OBJECTIVES

To evaluate the efficacy of PCA versus conventional analgesia (such as a nurse administering an analgesic upon a patient's request) for postoperative pain control.

SEARCH STRATEGY

Randomized controlled trials (RCTs) were identified from the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2004, Issue 3), MEDLINE (1966 to 2004), and EMBASE (1994 to 2004). Additional reports were identified from the reference lists of retrieved papers.

SELECTION CRITERIA

RCTs of PCA versus conventional analgesia that employed pain intensity as a primary or secondary outcome were selected. These trials included RCTs that compared PCA without a continuous background infusion versus conventional parenteral analgesic regimens. Studies that explicitly stated they involved patients with chronic pain were excluded.

DATA COLLECTION AND ANALYSIS

Trials were scored using the Oxford Quality Scale. Meta-analyses were performed of outcomes that included analgesic efficacy assessed by a Visual Analog Scale (VAS), analgesic consumption, patient satisfaction, length of stay and adverse effects. A sufficient number of the retrieved trials reported these parameters to permit meta-analyses.

MAIN RESULTS

Fifty-five studies with 2023 patients receiving PCA and 1838 patients assigned to a control group met inclusion criteria. PCA provided better pain control and greater patient satisfaction than conventional parenteral 'as-needed' analgesia. Patients using PCA consumed higher amounts of opioids than the controls and had a higher incidence of pruritus (itching) but had a similar incidence of other adverse effects. There was no difference in the length of hospital stay.

AUTHORS' CONCLUSIONS

This review provides evidence that PCA is an efficacious alternative to conventional systemic analgesia for postoperative pain control.

Opioids for neuropathic pain

BACKGROUND

The use of opioids for neuropathic pain remains controversial. Studies have been small, have yielded equivocal results, and have not established the long-term risk-benefit ratio of this treatment.

OBJECTIVES

To assess the efficacy and safety of opioid agonists for the treatment of neuropathic pain.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (2nd Quarter 2005), MEDLINE (1966 to June 2005), and EMBASE (1980 to 2005 Week 27) for articles in any language, and reference lists of reviews and retrieved articles.

SELECTION CRITERIA

Trials were included in which opioid agonists were given to treat central or peripheral neuropathic pain of any etiology, pain was assessed using validated instruments, and adverse events were reported. Studies in which drugs other than opioid agonists were combined with opioids or opioids were administered epidurally or intrathecally were excluded.

DATA COLLECTION AND ANALYSIS

Data were extracted by two independent investigators and included demographic variables, diagnoses, interventions, efficacy, and adverse effects.

MAIN RESULTS

Twenty-three trials met the inclusion criteria and were classified as short-term (less than 24 hours; n = 14) or intermediate-term (median = 28 days; range = eight to 70 days; n = 9). The short-term trials had contradictory results. In contrast all nine intermediate-term trials demonstrated opioid efficacy for spontaneous neuropathic pain. Meta-analysis of seven intermediate-term studies showed mean post-treatment visual analog scale scores of pain intensity after opioids to be 13 points lower on a scale from zero to 100 than after placebo (95% confidence interval -16 to -9; P < 0.00001). The most common adverse events were nausea (33% opioid versus 9% control: number needed to treat to harm (NNH) 4.2) and constipation (33% opioid versus 10% control: NNH 4.2), followed by drowsiness (29% opioid versus 12% control: NNH 6.2), dizziness (21% opioid versus 6% control: NNH 7.1), and vomiting (15% opioid versus 3% control: NNH 8.3). Where reported, 23 (11%) of 212 participants withdrew because of adverse events during opioid therapy versus nine (4%) of 202 receiving placebo.

AUTHORS' CONCLUSIONS

Short-term studies provide only equivocal evidence regarding the efficacy of opioids in reducing the intensity of neuropathic pain, whereas intermediate-term studies demonstrate significant efficacy of opioids over placebo, which is likely to be clinically important. Reported adverse events of opioids are common but not life threatening. Further randomized controlled trials are needed to establish long-term efficacy, safety (including addiction potential), and effects on quality of life.

Postoperative pain management: a practical review, part 2

PURPOSE

The pharmacotherapy and assessment of postoperative pain in general pharmacy practice settings are reviewed.

SUMMARY

Numerous factors related to all levels of society and the health care system contribute to suboptimal treatment of postoperative pain, despite awareness of this challenge for at least the past 30 years and the availability of potent analgesics and tools to help clinicians care for persons with postoperative pain. The consequences of acute pain include clinical, economic, and patient-reported outcomes; thus, improving the treatment of postoperative pain has the potential to improve health care from a broad perspective. Opioids remain the cornerstone of treatment of postoperative pain. Multimodal analgesia also has the potential to improve the pharmacotherapy of postoperative pain. In addition to the appropriate use of drugs, it is important that clinicians be comfortable with equianalgesic dosage conversion, helping ensure that analgesic-related adverse effects are minimal, assessing pain and function, and incorporating this information into patient care.

CONCLUSION

Providing optimal management of postoperative pain is a vital goal for all health care providers. There is substantial potential for pharmacists to help meet this goal.

Postoperative pain management: A practical review, part 1

PURPOSE

The pharmacotherapy and assessment of postoperative pain in general pharmacy practice settings are reviewed.

SUMMARY

Numerous factors related to all levels of society and the health care system contribute to suboptimal treatment of postoperative pain, despite awareness of this challenge for at least the past 30 years and the availability of potent analgesics and tools to help clinicians care for persons with postoperative pain. The consequences of acute pain include clinical, economic, and patient-reported outcomes; thus, improving the treatment of postoperative pain has the potential to improve health care from a broad perspective. Opioids remain the cornerstone of treatment of postoperative pain. Multimodal analgesia also has the potential to improve the pharmacotherapy of postoperative pain. In addition to the appropriate use of drugs, it is important that clinicians be comfortable with equianalgesic dosage conversion, helping ensure that analgesic-related adverse effects are minimal, assessing pain and function, and incorporating this information into patient care.

CONCLUSION

Providing optimal management of postoperative pain is a vital goal for all health care providers. There is substantial potential for pharmacists to help meet this goal.

NSAIDS or paracetamol, alone or combined with opioids, for cancer pain

BACKGROUND

NSAIDs are widely applied to treat cancer pain and are frequently combined with opioids in combination preparations for this purpose. However, it is unclear which agent is most clinically efficacious for relieving cancer-related pain, or even what may be the additional benefit of combining an NSAID with an opioid in this setting.

OBJECTIVES

To assess the effects of NSAIDs, alone or combined with opioids, for the treatment of cancer pain.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (Issue 2, 2002), MEDLINE (January 1966 to March 2003), EMBASE (January 1980 to December 2001), LILACS (January 1984 to December 2001) and reference list of articles.

SELECTION CRITERIA

Randomized controlled trials and controlled clinical trials that compared NSAID versus placebo; NSAID versus NSAID; NSAID versus NSAID plus opioid; opioid versus opioid plus NSAID; or NSAID versus opioid.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information. Adverse event information was collected from trials. Where there was disagreement between reviewers, the opinion of an additional reviewer was sought to resolve the issue.

MAIN RESULTS

Forty-two trials involving 3084 patients were included. Clinical heterogeneity of study methods and outcomes precluded meta-analyses and only supported a qualitative systematic review. Seven of eight papers that compared NSAID with placebo demonstrated superior efficacy of NSAID with no difference in side effects. Thirteen papers compared one NSAID with another; four reported increased efficacy of one NSAID over another. Four different studies found that one NSAID had fewer side effects than one or more others. Twenty-three studies compared NSAIDs and opioids in combination or alone with NSAID/opioid combinations. Thirteen out of 14 studies found no difference, or low clinical difference, when combining an NSAID plus an opioid versus either drug alone. Comparisons between various NSAID/opioid combinations were inconclusive. Nine studies assessed the association between dose and efficacy and safety. Four papers demonstrated increased efficacy with increased dose, but no dose-dependent increase in side effects within the dose ranges studied. Study duration ranged from single dose studies performed over six hours to crossover studies lasting six weeks; however the majority of studies were of less than seven days duration.

AUTHORS' CONCLUSIONS

Based upon limited data, NSAIDs appear to be more effective than placebo for cancer pain; clear evidence to support superior safety or efficacy of one NSAID over another is lacking; and trials of combinations of an NSAID with an opioid have disclosed either no difference (4 out of 14 papers), a statistically insignificant trend towards superiority (1 out of 14 papers), or at most a slight but statistically significant advantage (9 out of 14 papers), compared with either single entity. The short duration of studies undermines generalization of their findings on efficacy and safety of NSAIDs for cancer pain.

Nonsteroidal Anti-Inflammatory Drugs, Alone or Combined With Opioids, for Cancer Pain

Purpose

To assess the safety and efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs), alone or combined with opioids, for the treatment of cancer pain.

Patients and Methods

Forty-two trials involving 3,084 patients met inclusion criteria: eight compared NSAID with placebo; 13 compared one NSAID with another; 23 compared NSAID with opioid, NSAID or opioid versus NSAID plus opioid combinations, or NSAID plus opioid combinations versus NSAID plus opioid combinations; and nine studies assessed the effect of increasing NSAID dose.

Results

Sixteen studies lasted 1 week or longer and 11 evaluated a single dose. Seven of eight trials demonstrated superior efficacy of single doses of NSAID compared with placebo. Only four of 13 studies reported increased efficacy of one NSAID compared with another; four other studies found that one NSAID had fewer side effects than one or more others. Thirteen of 14 studies found no difference, or minimal clinical difference, when comparing an NSAID plus opioid combination versus either drug alone. Comparisons between various NSAID plus opioid combinations were inconclusive. Four studies demonstrated increased efficacy with increased NSAID dose, without dose-dependent increases in side effects.

Conclusion

Heterogeneity of study methods and outcomes precluded meta-analyses. Short duration of studies undermines generalization of findings on efficacy and safety. On the basis of limited data, NSAIDs appear to be more effective than placebo for cancer pain; clear evidence to support superior safety or efficacy of one NSAID compared with another is lacking; and trials of combinations of an NSAID with an opioid have disclosed either no significant difference, or at most a slight but statistically significant advantage, compared with either single entity.

Management of opioid side effects in cancer-related and chronic noncancer pain: a systematic review

Side effects can limit opioid dosage and reduce quality of life. The purpose of this systematic review was to assess the management of opioid side effects in the context of cancer pain management or, in the event that no evidence was available for cancer pain, for chronic noncancer pain. The side effects studied were constipation, pruritus, nausea and vomiting, myoclonus, sedation, respiratory depression, and delirium. Opioid rotation to manage side effects was also studied. For each side effect, we searched MEDLINE and the Cochrane Controlled Trials Register and identified 657 possible titles for inclusion. Of these, 67 studies met inclusion criteria for analysis. The lack of well-designed, randomized controlled trials and the heterogeneity of populations and study designs made the drawing of firm conclusions difficult and precluded performance of meta-analysis. The type, strength, and consistency of evidence for available interventions to manage opioid side effects vary from strong (eg, on the use of naloxone to reverse respiratory depression or constipation) to weak (eg, changing from the oral to epidural route of morphine administration to manage sedation). Well-designed trials in the specified populations are required to furnish clinicians with secure evidence on managing opioid side effects successfully.

Adverse reaction to extra-amniotic prostaglandin E2

An immediate and severe reaction to prostaglandin E2 (PGE2), given by the extra-amniotic route to induce the abortion of a hydatidiform mole, is reported.