Update in pain medicine for primary care providers: a narrative review, 2010-2012

Duloxetine, Gabapentin, and the Risk for Acute Myocardial Infarction, Stroke, and Out-of-Hospital Death in Medicare Beneficiaries With Non-Cancer Pain

OBJECTIVE

Duloxetine is a serotonin-norepinephrine reuptake inhibitor prescribed for musculoskeletal and other forms of chronic pain. Its dual pharmacologic properties have the potential to either raise or lower cardiovascular risk: adrenergic activity may increase the risk for acute myocardial infarction (AMI) and stroke, but antiplatelet activity may decrease risk. Gabapentin is another nonopioid medication used to treat pain, which is not thought to have adrenergic/antiplatelet effects. With the current emphasis on the use of nonopioid medications to treat patients with chronic pain, assessing cardiovascular risks associated with these medications among high-risk patients is important.

MATERIALS AND METHODS

We conducted a retrospective cohort study among a 20% sample of Medicare enrollees, aged 65 to 89, with chronic pain who were new users between 2015 and 2018 of either duloxetine (n = 34,009) or gabapentin (n = 233,060). We excluded individuals with cancer or other life-threatening conditions at study drug initiation. The primary outcome was a composite of AMI, stroke, and out-of-hospital mortality. We adjusted for comorbidity differences with time-dependent inverse probability of treatment weighting.

RESULTS

During 115,668 person-years of follow-up, 2361 patients had the composite primary outcome; the rate among new users of duloxetine was 16.7/1000 person-years compared with new users of gabapentin (21.1/1000 person-years), adjusted hazard ratio = 0.98 (95% CI: 0.83, 1.16). Results were similar for the individual components of the composite outcome as well as in analyses stratified by demographic and clinical characteristics.

DISCUSSION

In summary, cohort Medicare patients with non-cancer pain beginning treatment with duloxetine had rates of AMI, stroke, and out-of-hospital mortality comparable to those who initiated gabapentin.

Experiences of Military Primary Care Providers during Chronic Pain Visits: A Qualitative Descriptive Study

OBJECTIVE

Chronic pain complaints are the second most common reason for outpatient primary care visits, yet a comprehensive assessment of the processes and experiences of providers during a chronic pain visit is still lacking. This qualitative descriptive study aimed to conceptualize the processes and experiences that military primary care providers go through while they assess and manage chronic pain.

SETTING

Single US Army medical center.

METHODS

Semi-structured interviews with 12 military primary care providers. Interviews were audio-recorded, transcribed, and coded using qualitative software. Transcripts were analyzed using thematic analysis to identify emergent themes.

RESULTS

Three broad themes with associated sub-themes captured the processes and providers' experiences: 1) comprehending the pain story - asking the right questions regarding pain impact, navigating through complexities of the pain story, and conveying understanding of pain story back to the patient; 2) optimizing the pain story - perception of provider-patient disconnect on pain management goals, re-setting realistic goals, creating optimal individualized treatment plan, and evaluating treatment effectiveness; and 3) empathetic and therapeutic engagement with patients - trusting patients and fostering patient-provider relationship. A thematic map illustrates these provider experiences.

CONCLUSIONS

During chronic pain visits, the provider-patient disconnect on goals of chronic pain treatment presents a considerable challenge. Further in-depth studies on addressing provider-patient disconnect are warranted to identify solutions, which would help providers communicate realistic chronic pain management expectations to patients. The themes and sub-themes described in this study could serve as a guide for directing strategies to improve chronic pain visits in primary care.

Cognitive-behavioural therapy for a variety of conditions: an overview of systematic reviews and panoramic meta-analysis

BACKGROUND

Cognitive-behavioural therapy aims to increase quality of life by changing cognitive and behavioural factors that maintain problematic symptoms. A previous overview of cognitive-behavioural therapy systematic reviews suggested that cognitive-behavioural therapy was effective for many conditions. However, few of the included reviews synthesised randomised controlled trials.

OBJECTIVES

This project was undertaken to map the quality and gaps in the cognitive-behavioural therapy systematic review of randomised controlled trial evidence base. Panoramic meta-analyses were also conducted to identify any across-condition general effects of cognitive-behavioural therapy.

DATA SOURCES

The overview was designed with cognitive-behavioural therapy patients, clinicians and researchers. The Cochrane Library, MEDLINE, EMBASE, PsycINFO, Cumulative Index to Nursing and Allied Health Literature, Child Development & Adolescent Studies, Database of Abstracts of Reviews of Effects and OpenGrey databases were searched from 1992 to January 2019.

REVIEW METHODS

Study inclusion criteria were as follows: (1) fulfil the Centre for Reviews and Dissemination criteria; (2) intervention reported as cognitive-behavioural therapy or including one cognitive and one behavioural element; (3) include a synthesis of cognitive-behavioural therapy trials; (4) include either health-related quality of life, depression, anxiety or pain outcome; and (5) available in English. Review quality was assessed with A MeaSurement Tool to Assess systematic Reviews (AMSTAR)-2. Reviews were quality assessed and data were extracted in duplicate by two independent researchers, and then mapped according to condition, population, context and quality. The effects from high-quality reviews were pooled within condition groups, using a random-effect panoramic meta-analysis. If the across-condition heterogeneity was I2 < 75%, we pooled across conditions. Subgroup analyses were conducted for age, delivery format, comparator type and length of follow-up, and a sensitivity analysis was performed for quality.

RESULTS

A total of 494 reviews were mapped, representing 68% (27/40) of the categories of the International Classification of Diseases, Eleventh Revision, Mortality and Morbidity Statistics. Most reviews (71%, 351/494) were of lower quality. Research on older adults, using cognitive-behavioural therapy preventatively, ethnic minorities and people living outside Europe, North America or Australasia was limited. Out of 494 reviews, 71 were included in the primary panoramic meta-analyses. A modest effect was found in favour of cognitive-behavioural therapy for health-related quality of life (standardised mean difference 0.23, 95% confidence interval 0.05 to 0.41, prediction interval -0.05 to 0.50, I2 = 32%), anxiety (standardised mean difference 0.30, 95% confidence interval 0.18 to 0.43, prediction interval -0.28 to 0.88, I2 = 62%) and pain (standardised mean difference 0.23, 95% confidence interval 0.05 to 0.41, prediction interval -0.28 to 0.74, I2 = 64%) outcomes. All condition, subgroup and sensitivity effect estimates remained consistent with the general effect. A statistically significant interaction effect was evident between the active and non-active comparator groups for the health-related quality-of-life outcome. A general effect for depression outcomes was not produced as a result of considerable heterogeneity across reviews and conditions.

LIMITATIONS

Data extraction and analysis were conducted at the review level, rather than returning to the individual trial data. This meant that the risk of bias of the individual trials could not be accounted for, but only the quality of the systematic reviews that synthesised them.

CONCLUSION

Owing to the consistency and homogeneity of the highest-quality evidence, it is proposed that cognitive-behavioural therapy can produce a modest general, across-condition benefit in health-related quality-of-life, anxiety and pain outcomes.

FUTURE WORK

Future research should focus on how the modest effect sizes seen with cognitive-behavioural therapy can be increased, for example identifying alternative delivery formats to increase adherence and reduce dropout, and pursuing novel methods to assess intervention fidelity and quality.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017078690.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 9. See the NIHR Journals Library website for further project information.

Randomized Controlled Trial of Telephone-delivered Cognitive Behavioral Therapy Versus Supportive Care for Chronic Back Pain

OBJECTIVE

The objective of this study was to evaluate the efficacy of a telephone-delivered, home-based cognitive-behavioral intervention for chronic low back pain in comparison to a matched supportive care (SC) treatment.

METHODS

Participants (N=66) were patients with chronic back pain that were randomized to either an 8-week Cognitive-Behavioral Therapy (CBT) or a SC condition matched for contact frequency, format, and time. Participants completed validated measures of improvement in back pain disability, pain severity, and overall improvement.

RESULTS

Intent-to-treat analyses at posttreatment showed that the treatment groups not show significantly different improvements in back pain disability (mean changes, -2.4 and -2.6 for CBT and SC, respectively; Cohen d, 0.49 and 0.55, respectively) or reductions in pain severity (mean changes, -0.9 and -1.4 for CBT and SC respectively; Cohen d, 0.50, and 0.90, respectively). Participants rated their overall improvement levels at 31% (CBT) versus 18.5% (SC).

DISCUSSION

Results from this clinical trial suggest that home-based, telephone-delivered CBT and SC treatments did not significantly differ in their benefits for back pain severity and disability, and may warrant further research for applications to hospital settings. Major limitations included recruitment difficulties that underpowered primary analyses, the lack of objective improvement measures, and the absence of a usual care/untreated control group for comparisons.

Yoga: Can it be integrated with treatment of neuropathic pain?

Background

Neuropathic pain (NP) is a debilitating condition that may result from spinal cord injury (SCI). Nearly 75% of all SCI results in NP affecting 17,000 new individuals in the United States every year, and an estimated 7–10% of people worldwide. It is caused by damaged or dysfunctional nerve fibers sending aberrant signals to pain centers in the central nervous system causing severe pain that affects daily life and routine. The mechanisms underlying NP are not fully understood, making treatment difficult. Identification of specific molecular pathways that are involved in pain syndromes and finding effective treatments has become a major priority in current SCI research. Yoga has therapeutic applications may prove beneficial in treating subjects suffering chronically with SCI induced NP, chronic back and associated pains if necessary experimental data is generated

Summary

This review aims to discuss the implications of various mechanistic approaches of yoga which can be tested by new study designs around various nociceptive molecules including matrix metalloproteinases (MMPs), cation-dependent chloride transporter (NKCC1) etc in SCI induced NP patients.

Key messages

Thus, yogic practices could be used in managing SCI induced NP pain by regulating the action of various mechanisms and its associated molecules. Modern prescriptive treatment strategies combined with alternative approaches like yoga should be used in rehabilitation centers and clinics in order to ameliorate chronic NP. We recommend practical considerations of careful yoga practice as part of an integrative medicine approach for NP associated with SCI.

Harms and benefits of opioids for management of non-surgical acute and chronic low back pain: a systematic review

Background

Consequences of prescription opioid use involve harms, addiction, tolerance and death. Despite routine prescription, opioids are not recommended for initial intervention by any major multidisciplinary low back pain (LBP) guideline.

Objective

Our primary purpose was to improve overall understanding of the harms and benefits associated with oral opioid interventions prescribed for treatment of acute or chronic back pain. Our second goal was to evaluate pain intensity and to compare and contrast these data with the harms. Our last objective was to evaluate conflicts of interest among the study authors and the findings.

Design/data/eligibility criteria

Studies incorporating oral prescription opioid management of non-surgical LBP were evaluated. After systematic assessment, no studies that met inclusion included participants with specifically acute LBP. Therefore, extracted data reflects only populations with subacute and chronic LBP. Data on reported harms, severe harms, pain outcomes and withdrawal rates were extracted and meta-analyses were completed for opioid versus placebo trials and opioids versus non-opioid trials.

Results

Fourteen studies met inclusion/exclusion requirements. All trials involved short-term management with limited follow-up. A high percentage of harms were identified across most studies. Opioids were not shown to be superior to other medications, and only showed superiority to placebo comparators (at cost of additional harms).

Conclusion

This review identified trends of higher harms rates and higher percentages of severe harms in opioid arms for the management of subacute and chronic LBP. The majority of trials that demonstrated benefits with opioids also had potential conflicts of interest. Lastly, non-opioid medications demonstrated statistically significant pain improvement compared with opioids. We feel that the results of the trial are supportive of current LBP guidelines and do not condone the initial use of opioids in management of subacute or chronic LBP.

Trial registration number

CRD42017070914

Long-term disability after blunt chest trauma: Don't miss chronic neuropathic pain!

Introduction The main objective of this prospective study was to assess the incidence of chronic pain and long-term respiratory disability in a single-center cohort of severe blunt chest trauma patients. Methods Over a 10-month period, all consecutive blunt chest trauma patients admitted in Intensive Care Unit (ICU) were screened to participate in a 3-month and 12-month follow-up. The following variables were prospectively assessed: persistence of chronic chest pain requiring regular used of analgesics, neuropathic pain, respiratory disability, physical and mental health status. Univariate and multivariable analysis were conducted to assess variables associated with chronic chest pain, neuropathic chest pain and respiratory disability. Results During the study period, 65 patients were included in the study. Chronic chest pain and respiratory disability were reported in 62% and 57% of patients respectively at 3 months postinjury. Neuropathic pain was reported in 22% of patients, associated with higher impairment of quality of life. A thoracic trauma severity score ≥12 and a pain score ≥4 at SICU discharge were the only variables significantly associated with the occurrence of neuropathic pain at 3 months (OR = 7 [2-32], p = 0.01 and OR = 16 [4-70], p < 0.0001). Conclusion According to the current study, chronic pain and long-term respiratory disability are very common after severe blunt chest trauma patients. Special attention should be paid to neuropathic pain, frequently under-diagnosed and responsible for significant impairment of quality of life.

Risk based in vitro performance assessment of extended release abuse deterrent formulations

High strength extended release opioid products, which are indispensable tools in the management of pain, are associated with serious risks of unintentional and potentially fatal overdose, as well as of misuse and abuse that might lead to addiction. The issue of drug abuse becomes increasingly prominent when the dosage forms can be readily manipulated to release a high amount of opioid or to extract the drug in certain products or solvents. One approach to deter opioid drug abuse is by providing novel abuse deterrent formulations (ADF), with properties that may be viewed as barriers to abuse of the product. However, unlike regular extended release formulations, assessment of ADF technologies are challenging, in part due to the great variety of formulation designs available to achieve deterrence of abuse by oral, parenteral, nasal and respiratory routes. With limited prior history or literature information, and lack of compendial standards, evaluation and regulatory approval of these novel drug products become increasingly difficult. The present article describes a risk-based standardized in-vitro approach that can be utilized in general evaluation of abuse deterrent features for all ADF products.

Priority interventions to improve the management of chronic non-cancer pain in primary care: a participatory research of the ACCORD program

PURPOSE

There is evidence that the management of chronic non-cancer pain (CNCP) in primary care is far from being optimal. A 1-day workshop was held to explore the perceptions of key actors regarding the challenges and priority interventions to improve CNCP management in primary care.

METHODS

Using the Chronic Care Model as a conceptual framework, physicians (n=6), pharmacists (n=6), nurses (n=6), physiotherapists (n=6), psychologists (n=6), pain specialists (n=6), patients (n=3), family members (n=3), decision makers and managers (n=4), and pain researchers (n=7) took part in seven focus groups and five nominal groups.

RESULTS

Challenges identified in focus group discussions were related to five dimensions: knowledge gap, "work in silos", lack of awareness that CNCP represents an important clinical problem, difficulties in access to health professionals and services, and patient empowerment needs. Based on the nominal group discussions, the following priority interventions were identified: interdisciplinary continuing education, interdisciplinary treatment approach, regional expert leadership, creation and definition of care paths, and patient education programs.

CONCLUSION

Barriers to optimal management of CNCP in primary care are numerous. Improving its management cannot be envisioned without considering multifaceted interventions targeting several dimensions of the Chronic Care Model and focusing on both clinicians and patients.

Modeled behavior of neuropathic pain with social defect in rats: a preliminary methodology evaluation

Background

Social defect and chronic pain are 2 major health problems and recent data has demonstrated that they generally exist concurrently. However, a powerful evaluation model on the behavioral change is lacking. This study was designed to evaluate the behavioral curves using a statistically modeled trajectory analysis in neuropathic animals with or without social defect exposure.

Material/Methods

After approval by the institutional animal care committee, Sprague-Dawley rats were randomized into different interventional groups with 15 animals each. Sprague-Dawley rats underwent spared nerve injury (SNI) to establish the neuropathic pain model, of which the mechanical withdrawal threshold was measured using von Frey filaments for a period of 105 days. Otherwise, a modified version of the resident (Long-Evans rats)-intruder paradigm was applied to produce a social defect animal model through the elevated plus maze (EPM). After raw data collection, we modeled them into a powerful statistical effects analysis to build up the behavioral change tendency in single SNI or in combined SNI and social defect animals.

Results

The random and fixed effects analyses of the pain behavior after SNI were successfully modeled and demonstrated a gradient recovery tendency during the 15-week post-injury observational period. Correspondingly, SNI rats exhibited increased social defected symptoms, as indicated by the increased anxiety-like behavior in the EPM test. In addition, continuous social defect stress for 5 days or 10 days, respectively, partially attenuated and exacerbated SNI-induced allodynia in both random and fixed effects models. Five days but not 10 days social defect ameliorated SNI-associated anxiety-like behavior.

Conclusions

These data suggest that statistically powerful analysis of nerve injury-induced neuropathic pain is a highly sensitive model to determine the behavioral change tendency and distinguish them among behavior curves with or without social defect, and the combination of SNI with resident-intruder paradigm may be a suitable model for behavior evaluation of neuropathic pain with social defect.

The Mu opioid receptor promotes opioid and growth factor-induced proliferation, migration and Epithelial Mesenchymal Transition (EMT) in human lung cancer

Recent epidemiologic studies implying differences in cancer recurrence based on anesthetic regimens raise the possibility that the mu opioid receptor (MOR) can influence cancer progression. Based on our previous observations that overexpression of MOR in human non-small cell lung cancer (NSCLC) cells increased tumor growth and metastasis, this study examined whether MOR regulates growth factor receptor signaling and epithelial mesenchymal transition (EMT) in human NSCLC cells. We utilized specific siRNA, shRNA, chemical inhibitors and overexpression vectors in human H358 NSCLC cells that were either untreated or treated with various concentrations of DAMGO, morphine, fentanyl, EGF or IGF. Cell function assays, immunoblot and immunoprecipitation assays were then performed. Our results indicate MOR regulates opioid and growth factor-induced EGF receptor signaling (Src, Gab-1, PI3K, Akt and STAT3 activation) which is crucial for consequent human NSCLC cell proliferation and migration. In addition, human NSCLC cells treated with opioids, growth factors or MOR overexpression exhibited an increase in snail, slug and vimentin and decrease ZO-1 and claudin-1 protein levels, results consistent with an EMT phenotype. Further, these effects were reversed with silencing (shRNA) or chemical inhibition of MOR, Src, Gab-1, PI3K, Akt and STAT3 (p<0.05). Our data suggest a possible direct effect of MOR on opioid and growth factor-signaling and consequent proliferation, migration and EMT transition during lung cancer progression. Such an effect provides a plausible explanation for the epidemiologic findings.