Cross-sectional evaluation of patient functioning and health-related quality of life in patients with neuropathic pain under standard care conditions

Prevalence and Risk Factors for Chronic Postsurgical Pain after Cardiac Surgery: A Single-center Prospective Cohort Study

BACKGROUND

Chronic postsurgical pain is a common complication of surgery. The role of psychologic risk factors like depression and anxiety is substantially understudied in cardiac surgery. This study sought to identify perioperative factors associated with chronic pain at 3, 6, and 12 months after cardiac surgery. The authors hypothesize that baseline psychologic vulnerabilities have a negative influence on chronic postsurgical pain.

METHODS

The authors prospectively collected demographic, psychologic, and perioperative factors in a cohort of 1,059 patients undergoing cardiac surgery at the Toronto General Hospital between 2012 and 2020. Patients were followed and completed chronic pain questionnaires at 3, 6, and 12 months after surgery.

RESULTS

The study included 767 patients who completed at least one follow-up questionnaire. The incidence of postsurgical pain (more than 0 out of 10) at 3, 6, and 12 months after surgery was 191 of 663 (29%), 118 of 625 (19%), and 89 of 605 (15%), respectively. Notably, among patients reporting any pain, the incidence of pain compatible with a neuropathic phenotype increased from 56 of 166 (34%) at 3 months to 38 of 97 (39%) at 6 months and 43 of 67 (64%) at 12 months. Factors associated with postsurgical pain scores at 3 months include female sex, pre-existing chronic pain, previous cardiac surgery, preoperative depression, baseline pain catastrophizing scores, and moderate-to-severe acute pain (4 or more out of 10) within 5 postoperative days.

CONCLUSIONS

Nearly one in three patients undergoing cardiac surgery reported pain at 3 months of follow-up, with approximately 15% reporting persistent pain at 1 yr. Female sex, pre-existing chronic pain, and baseline depression were associated with postsurgical pain scores across all three time periods.

EDITOR’S PERSPECTIVE

BDNF as a biomarker for neuropathic pain: Consideration of mechanisms of action and associated measurement challenges

INTRODUCTION

The primary objective of this paper is to (1) provide a summary of human studies that have used brain derived neurotrophic factor (BDNF) as a biomarker, (2) review animal studies that help to elucidate the mechanistic involvement of BDNF in the development and maintenance of neuropathic pain (NP), and (3) provide a critique of the existing measurement techniques to highlight the limitations of the methods utilized to quantify BDNF in different biofluids in the blood (i.e., serum and plasma) with the intention of presenting a case for the most reliable and valid technique. Lastly, this review also explores potential moderators that can influence the measurement of BDNF and provides recommendations to standardize its quantification to reduce the inconsistencies across studies.

METHODS

In this manuscript we examined the literature on BDNF, focusing on its role as a biomarker, its mechanism of action in NP, and critically analyzed its measurement in serum and plasma to identify factors that contribute to the discrepancy in results between plasma and serum BDNF values.

RESULTS

A large heterogenous literature was reviewed that detailed BDNF's utility as a potential biomarker in healthy volunteers, patients with chronic pain, and patients with neuropsychiatric disorders but demonstrated inconsistent findings. The literature provides insight into the mechanism of action of BDNF at different levels of the central nervous system using animal studies. We identified multiple factors that influence the measurement of BDNF in serum and plasma and based on current evidence, we recommend assessing serum BDNF levels to quantify peripheral BDNF as they are more stable and sensitive to changes than plasma BDNF.

CONCLUSION

Although mechanistic studies clearly explain the role of BDNF, results from human studies are inconsistent. More studies are needed to evaluate the methodological challenges in using serum BDNF as a biomarker in NP.

Cross-Sectional Evaluation of the Economic Burden on Patients Seeking Surgical Treatment for Chronic Nerve Injuries

INTRODUCTION

Little emphasis has been paid toward characterizing the socioeconomic burdens experienced by patients seeking treatment for chronic nerve injuries. The aim of this study was to characterize the direct and indirect costs faced by patients with chronic nerve injuries and their attendant health care utilization.

MATERIALS AND METHODS

A cross-sectional survey was distributed to all patients (N = 767) from a single nerve surgeon's practice treated for chronic nerve injuries in the ambulatory setting between 2014 and 2020. Data collected included demographics, etiology, comorbidities, duration and severity of symptoms, history of prior medical and interventional treatments, work or school time lost due to injury or treatment, money spent on treatment, and health care utilization.

RESULTS

Of the 767 patients, 209 (27.2%) completed the survey. Average age was 48.8 (SD = 19.1) years, 68.9% female and 31.1% male. Patients with chronic nerve injury reported significant direct costs, indirect costs, and health care utilization associated with their nerve injury symptoms. Direct costs consisted of out-of-pocket spending (68.4% had spent >$1000 per year), physician specialists visits (71.3% had seen at least 4 specialists), and prior interventional procedures intended to address symptoms. Indirect costs included lost time from work or school (24.6% had missed more than 12 months). Health care utilization, represented by annual emergency room visits and hospitalizations related to nerve symptoms, was increased relative to the general population. Detailed statistics are presented in the manuscript.

CONCLUSIONS

Chronic nerve injuries may be associated with a notable socioeconomic burden to the patient, including missed work or school, frequent physician visits and procedures, hospital visits, and out-of-pocket costs. Interdisciplinary algorithms recognizing a role for surgical evaluation in patients with chronic neuropathic pain due to underlying nerve injuries would facilitate future research into whether timely surgical intervention may reduce this economic burden.

Modulatory Effects of Actual and Imagined Acupuncture on the Functional Connectivity of the Periaqueductal Gray and Ventral Tegmental Area

OBJECTIVE

Both acupuncture and guided imagery hold promise for treating pain. The mechanisms underlying these alternative interventions remain unclear. The reported study aimed to comparatively investigate the modulation effect of actual and imagined acupuncture on the functional connectivity of descending pain modulation system and reward network.

METHODS

Twenty-four healthy participants (mean [standard error], 25.21 [0.77] years of age; 66.67% female) completed a crossover study that included five sessions, a training session and four intervention sessions administered in randomized order. We investigated the modulation effect of real acupuncture, sham acupuncture, video-guided acupuncture imagery treatment (VGAIT) and VGAIT control on the resting-state functional connectivity (rsFC) of periaqueductal gray (PAG) and ventral tegmental area (VTA). These are key regions of the descending pain modulatory system and dopaminergic reward system, respectively.

RESULTS

Compared with sham acupuncture, real acupuncture produced decreased PAG-precuneus (Pcu) rsFC and increased VTA-amygdala/hippocampus rsFC. Heat pain threshold changes applied on the contralateral forearm were significantly associated with the decreased PAG-Pcu (r = 0.49, p = .016) and increased VTA-hippocampus rsFC (r = -0.77, p < .001). Compared with VGAIT control, VGAIT produced decreased PAG-paracentral lobule/posterior cingulate cortex/Pcu, middle cingulate cortex (MCC), and medial prefrontal cortex rsFC, and decreased VTA-caudate and MCC rsFC. Direct comparison between real acupuncture and VGAIT showed that VGAIT decreased rsFC in PAG-paracentral lobule/MCC, VTA-caudate/anterior cingulate cortex/nucleus accumbens, and VTA-MCC.

CONCLUSIONS

Results suggest that both actual and imagined acupuncture can modulate key regions in the descending pain modulatory system and reward networks, but through different pathways. Identification of different pain relief mechanisms may facilitate the development of new pain management methods.

Percutaneous Electrical Nerve Stimulation (PENS) as a Rehabilitation Approach for Reducing Mixed Chronic Pain in Patients with Musculoskeletal Disorders

“Mixed pain” is a term recently introduced to define the overlapping of nociceptive, neuropathic and nociplastic pain. To date, it has been reported that pharmacological treatments might have a modest effectiveness on patients affected by mixed chronic pain, with detrimental consequences in terms of disability, physical function and health-related quality of life. In this scenario, Percutaneous Electrical Nerve Stimulation (PENS), a mini-invasive neuromodulation technique, has been recently suggested as a promising approach for the complex management of mixed pain in musculoskeletal disorders. Albeit PENS showed to be effective in reducing unspecified pain in several chronic pain conditions, there is still a lack of evidence in the literature about its role in the management of neuropathic or mixed pain not responsive to pharmacological treatments. Therefore, by the present scoping review, we portray the potential effects of PENS in the multidisciplinary and multidimensional management of mixed chronic pain in patients with musculoskeletal disorders.

When to consider "mixed pain"? The right questions can make a difference!

The term "mixed pain" is increasingly applied for specific clinical scenarios, such as low back pain, cancer pain and postsurgical pain, in which there "is a complex overlap of the different known pain types (nociceptive, neuropathic, nociplastic) in any combination, acting simultaneously and/or concurrently to cause pain in the same body area." Whether mixed pain is the manifestation of neuropathic and nociceptive mechanisms operating simultaneously or concurrently, or the result of an entirely independent pathophysiological mechanism - distinct from nociceptive, nociplastic and neuropathic pain - is currently unknown. At present, the diagnosis of mixed pain is made based on clinical judgement following detailed history-taking and thorough physical examination, rather than by formal confirmation following explicit screening or diagnostic criteria; this lack of formalized screening or diagnostic tools for mixed pain is problematic for physicians in primary care, who encounter patients with probable mixed pain states in their daily practice. This article outlines a methodical approach to clinical evaluation of patients presenting with acute, subacute or chronic pain, and to possibly identifying those who have mixed pain. The authors propose the use of nine simple key questions, which will provide the practicing clinician a framework for identifying the predominant pain mechanisms operating within the patient. A methodical, fairly rapid, and comprehensive assessment of a patient in chronic pain - particularly one suffering from pain with both nociceptive and neuropathic components - allows validation of their experience of chronic pain as a specific disease and, importantly, allows the institution of targeted treatment.

Molecular, circuit, and anatomical changes in the prefrontal cortex in chronic pain

The prefrontal cortex undergoes functional and structural reorganization in chronic pain conditions in both rodents and humans. We provide an illustrated overview of the molecular, functional, and connectivity pathology occurring in the prefrontal cortex in chronic pain states.

Bibliometric Analysis of Exercise and Neuropathic Pain Research

Background

Neuropathic pain, a type of chronic pain, is difficult to treat clinically. Mounting evidence suggests that exercise can effectively ease neuropathic pain, and the number of publications related to exercise and neuropathic pain has increased over time. However, bibliometrics is rarely used in analyzing the general aspects of studies on exercise and neuropathic pain. The present study aims to provide a systematic overview of global scientific research related to exercise and neuropathic pain from 2005 to 2019.

Methods

Publications on Science Citation Index - Expanded of Web of Science from 2005 to 2019 were searched, and those related to exercise and neuropathic pain were analyzed. Only English papers were included without specific species restrictions.

Results

A total of 676 papers were included in accordance with our adopted criteria. Linear regression analysis showed a statistically meaningful increase in the number of publications on exercise and neuropathic pain study over time (p< 0.001). The subject categories of the 676 papers mainly focused on neuroscience (29.88%), clinical neurology (18.79%) and rehabilitation (10.06%) in Web of Science. In terms of contribution to scientific research on exercise and neuropathic pain, the United States led the first echelon and had the largest numbers of published papers, citations and H-index.

Conclusion

The findings in our study may provide researchers useful information about research trends and frontiers, cooperators and cooperative institutions.

Three-Year Outcomes After Dorsal Root Ganglion Stimulation in the Treatment of Neuropathic Pain After Peripheral Nerve Injury of Upper and Lower Extremities

OBJECTIVES

Traumatic peripheral nerve injuries (PNI) often result in severe neuropathic pain which typically becomes chronic, is recalcitrant to common analgesics, and is associated with sleep disturbances, anxiety, and depression. Pharmacological treatments proven to be effective against neuropathic pain are not well tolerated due to side effects. Neuromodulative interventions such as peripheral nerve or spinal cord stimulation have generated mixed results and may be limited by reduced somatotopic specificity. Dorsal root ganglion (DRG) stimulation may be more effective in this etiology.

MATERIALS AND METHODS

Twenty-seven patients were trialed with a DRG neurostimulation system for PNI; trial success (defined as ≥50% pain relief) was 85%, and 23 patients received a permanent stimulator. However, 36-month outcome data was only available for 21 patients. Pain, quality of life, mental and physical function, and opioid usage were assessed at baseline and at 3-, 6-, 12-, 18-, 24-, and 36 months post-permanent implant. Implant-related complications were also documented.

RESULTS

Compared to baseline, we observed a significant pain relief (p < 0.001) at 3 (58%), 12 (66%), 18 (69%), 24 (71%), and 36 months (73%) in 21 patients (52.5 ± 14.2 years; 12 female), respectively. Mental and physical function showed immediate and sustained improvements. Participants reported improvements in quality of life. Opioid dosage reduced significantly (p < 0.001) at 3 (30%), 12 (93%), 18 (98%), 24 (99%), and 36 months (99%), and 20 of 21 patients were completely opioid-free after 36 months. There were five lead migrations and two electrode fractures (corrected by surgical intervention) and one wound infection (conservatively managed).

CONCLUSIONS

DRG neuromodulation appears to be a safe, effective, and durable option for treating neuropathic pain caused by PNI. The treatment allows cessation of often ineffective pharmacotherapy (including opioid misuse) and significantly improves quality of life.

Reversal of peripheral nerve injury-induced neuropathic pain and cognitive dysfunction via genetic and tomivosertib targeting of MNK

Neuropathic pain caused by nerve injury presents with severe spontaneous pain and a variety of comorbidities, including deficits in higher executive functions. None of these clinical problems are adequately treated with current analgesics. Targeting of the mitogen-activated protein kinase-interacting kinase (MNK1/2) and its phosphorylation target, the mRNA cap binding protein eIF4E, attenuates many types of nociceptive plasticity induced by inflammatory mediators and chemotherapeutic drugs but inhibiting this pathway does not alter nerve injury-induced mechanical allodynia. We used genetic manipulations and pharmacology to inhibit MNK-eIF4E activity in animals with spared nerve injury, a model of peripheral nerve injury (PNI)-induced neuropathic pain. We assessed the presence of spontaneous pain using conditioned place preference. We also tested performance in a medial prefrontal cortex (mPFC)-dependent rule-shifting task. WT neuropathic animals showed signs of spontaneous pain and were significantly impaired in the rule-shifting task while genetic and pharmacological inhibition of the MNK-eIF4E signaling axis protected against and reversed spontaneous pain and PNI-mediated cognitive impairment. Additionally, pharmacological and genetic inhibition of MNK-eIF4E signaling completely blocked and reversed maladaptive shortening in the length of axon initial segments (AIS) in the mPFC of PNI mice. Surprisingly, these striking positive outcomes on neuropathic pain occurred in the absence of any effect on mechanical allodynia, a standard test for neuropathic pain efficacy. Our results illustrate new testing paradigms for determining preclinical neuropathic pain efficacy and point to the MNK inhibitor tomivosertib (eFT508) as an important drug candidate for neuropathic pain treatment.

Pregabalin and gabapentin in neuropathic pain management after spinal cord injury: a systematic review and meta-analysis

Neuropathic pain after spinal cord injury (SCI) has a significant negative impact on the patients’ quality of life. The objective of this systematic review is to examine the safety and efficacy of pregabalin (PGB) and gabapentin (GBP) in the treatment of neuropathic pain due to SCI. PubMed, the Cochrane Library, Embase, Scopus, and the Web of Science were searched up to December 2018. The reference lists of key and review studies were reviewed for additional citations. The quality of the studies was evaluated using the Cochrane Collaboration’s tools for assessing the risk of bias. A meta-analysis was performed for primary and secondary outcomes. Eight studies were eligible for inclusion. Meta-analysis of PGB vs. placebo showed that PGB was effective for neuropathic pain (standardized mean difference [SMD] = −0.40; 95% confidence interval [CI]: −0.78, −0.01), anxiety (MD = −0.68; 95% CI: −0.77, −0.59), depression (mean difference [MD] = −0.99; 95% CI: −1.08, −0.89), and sleep interference (MD = −1.08; 95% CI: −1.13, −1.02). Also, GBP was more effective than a placebo for reducing pain. No significant difference was observed between the efficacy of the two drugs (MD = −0.37; 95% CI: −1.67, 0.93). There was no significant difference between the two drugs for discontinuation due to adverse events (risk ratio = 3.00; 95% CI: 0.81, 11.15). PGB and GBP were effective vs. placebos in decreasing neuropathic pain after SCI. Also, there was no significant difference between the two drugs for decreasing pain and adverse events.

Mediators and moderators of change in mindfulness-based stress reduction for painful diabetic peripheral neuropathy

Painful diabetic peripheral neuropathy (PDPN) is a chronic pain condition with modest response to pharmacotherapy. Participation in mindfulness-based stress reduction (MBSR) leads to improvements in pain-related outcomes but the mechanisms of change are unknown. The present study examined the mediators and moderators of change in 62 patients with PDPN who participated in a randomized controlled trial comparing MBSR to waitlist. Changes in mindfulness and pain catastrophizing were tested simultaneously as mediators. Increased mindfulness mediated the association between participation in MBSR and improved pain severity, pain interference, and the physical component of health-related quality of life (HRQoL) 3 months later. The mediation effect of pain catastrophizing was not significant. Linear moderated trends were also found. Post-hoc moderated mediation analyses suggested that MBSR patients with longer histories of diabetes might increase their mindfulness levels more, which in turn leads to improved pain severity and physical HRQoL. These results allow for a deeper understanding of pathways by which MBSR benefits patients with PDPN.

Current understanding of the mixed pain concept: a brief narrative review

Despite having been referenced in the literature for over a decade, the term "mixed pain" has never been formally defined. The strict binary classification of pain as being either purely neuropathic or nociceptive once left a good proportion of patients unclassified; even the recent adoption of "nociplastic pain" in the IASP Terminology leaves out patients who present clinically with a substantial overlap of nociceptive and neuropathic symptoms. For these patients, the term "mixed pain" is increasingly recognized and accepted by clinicians. Thus, an independent group of international multidisciplinary clinicians convened a series of informal discussions to consolidate knowledge and articulate all that is known (or, more accurately, thought to be known) and all that is not known about mixed pain. To inform the group's discussions, a Medline search for the Medical Subject Heading "mixed pain" was performed via PubMed. The search strategy encompassed clinical trial articles and reviews from January 1990 to the present. Clinically relevant articles were selected and reviewed. This paper summarizes the group's consensus on several key aspects of the mixed pain concept, to serve as a foundation for future attempts at generating a mechanistic and/or clinical definition of mixed pain. A definition would have important implications for the development of recommendations or guidelines for diagnosis and treatment of mixed pain.

Neuropathic Pain Creates an Enduring Prefrontal Cortex Dysfunction Corrected by the Type II Diabetic Drug Metformin But Not by Gabapentin

Chronic pain patients suffer from pain-related cognitive deficits, even when taking commonly prescribed analgesics. These deficits are likely related to pain-related maladaptive plasticity in the frontal cortex. We sought to model cognitive deficits in mice with neuropathic pain to examine maladaptive morphological plasticity in the mPFC and to assess the effects of several therapeutics. We used an attentional set-shifting task in mice with spared nerve injury (SNI) who received either a single intrathecal injection of an analgesic dose of clonidine, 7 d of 100 mg/kg gabapentin, or 7 d of 200 mg/kg metformin. Male SNI mice were significantly more impaired in the set-shifting task than females. This deficit correlated with a loss of parvalbumin (PV) and reductions in axon initial segment (AIS) length in layers 5/6 of the infralimbic (IL) cortex. Acute pain relief with clonidine had no effect on set-shifting performance, whereas pain relief via 7 day treatment with gabapentin worsened the impairment in both SNI and sham mice. Gabapentin reversed the PV loss in the IL but had no effect on AIS length. Treatment with the AMPK-activator metformin completely reversed the pain-related cognitive impairment and restored AIS length in the IL but had little effect on PV expression. Our findings reveal that neuropathic pain-related cognitive impairments in male mice are correlated to bilateral morphological changes in PV interneurons and layer 5/6 IL pyramidal neuron AIS. Pain relief with metformin can reverse some of the functional and anatomical changes.SIGNIFICANCE STATEMENT Cognitive impairments are a comorbidity of neuropathic pain but are inadequately addressed by existing therapeutics. We used a neuropathic pain model in mice to demonstrate that male (but not female) mice show a robust pain-related deficit in attentional set-shifting, which is associated with structural plasticity in axon initial segments in the infralimbic cortex. These deficits were completely reversed by 7 day treatment with the antidiabetic drug metformin, suggesting that this drug can be repurposed for the treatment of neuropathic pain and its cognitive comorbidities. Our findings have implications for our understanding of how neuropathic pain causes structural plasticity in the brain, and they point to a marked sexual dimorphism in neuropathic pain mechanisms in mice.

Randomized Trial of the Effect of Mindfulness-Based Stress Reduction on Pain-Related Disability, Pain Intensity, Health-Related Quality of Life, and A1C in Patients With Painful Diabetic Peripheral Neuropathy

IN BRIEF Painful diabetic peripheral neuropathy (PDPN) has a large negative impact on patients' physical and mental functioning, and pharmacological therapies rarely provide more than partial relief. Mindfulness-based stress reduction (MBSR) is a group psychosocial intervention that was developed for patients with chronic illness who were not responding to existing medical treatments. This study tested the effects of community-based MBSR courses for patients with PDPN. Among patients whose PDPN pharmacotherapy had been optimized in a chronic pain clinic, those randomly assigned to treatment with MBSR experienced improved function, better health-related quality of life, and reduced pain intensity, pain catastrophizing, and depression compared to those receiving usual care.

Dexamethasone as an adjuvant to peripheral nerve block

BACKGROUND

Peripheral nerve block (infiltration of local anaesthetic around a nerve) is used for anaesthesia or analgesia. A limitation to its use for postoperative analgesia is that the analgesic effect lasts only a few hours, after which moderate to severe pain at the surgical site may result in the need for alternative analgesic therapy. Several adjuvants have been used to prolong the analgesic duration of peripheral nerve block, including perineural or intravenous dexamethasone.

OBJECTIVES

To evaluate the comparative efficacy and safety of perineural dexamethasone versus placebo, intravenous dexamethasone versus placebo, and perineural dexamethasone versus intravenous dexamethasone when added to peripheral nerve block for postoperative pain control in people undergoing surgery.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, DARE, Web of Science and Scopus from inception to 25 April 2017. We also searched trial registry databases, Google Scholar and meeting abstracts from the American Society of Anesthesiologists, the Canadian Anesthesiologists' Society, the American Society of Regional Anesthesia, and the European Society of Regional Anaesthesia.

SELECTION CRITERIA

We included all randomized controlled trials (RCTs) comparing perineural dexamethasone with placebo, intravenous dexamethasone with placebo, or perineural dexamethasone with intravenous dexamethasone in participants receiving peripheral nerve block for upper or lower limb surgery.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 35 trials of 2702 participants aged 15 to 78 years; 33 studies enrolled participants undergoing upper limb surgery and two undergoing lower limb surgery. Risk of bias was low in 13 studies and high/unclear in 22. Perineural dexamethasone versus placeboDuration of sensory block was significantly longer in the perineural dexamethasone group compared with placebo (mean difference (MD) 6.70 hours, 95% confidence interval (CI) 5.54 to 7.85; participants1625; studies 27). Postoperative pain intensity at 12 and 24 hours was significantly lower in the perineural dexamethasone group compared with control (MD -2.08, 95% CI -2.63 to -1.53; participants 257; studies 5) and (MD -1.63, 95% CI -2.34 to -0.93; participants 469; studies 9), respectively. There was no significant difference at 48 hours (MD -0.61, 95% CI -1.24 to 0.03; participants 296; studies 4). The quality of evidence is very low for postoperative pain intensity at 12 hours and low for the remaining outcomes. Cumulative 24-hour postoperative opioid consumption was significantly lower in the perineural dexamethasone group compared with placebo (MD 19.25 mg, 95% CI 5.99 to 32.51; participants 380; studies 6). Intravenous dexamethasone versus placeboDuration of sensory block was significantly longer in the intravenous dexamethasone group compared with placebo (MD 6.21, 95% CI 3.53 to 8.88; participants 499; studies 8). Postoperative pain intensity at 12 and 24 hours was significantly lower in the intravenous dexamethasone group compared with placebo (MD -1.24, 95% CI -2.44 to -0.04; participants 162; studies 3) and (MD -1.26, 95% CI -2.23 to -0.29; participants 257; studies 5), respectively. There was no significant difference at 48 hours (MD -0.21, 95% CI -0.83 to 0.41; participants 172; studies 3). The quality of evidence is moderate for duration of sensory block and postoperative pain intensity at 24 hours, and low for the remaining outcomes. Cumulative 24-hour postoperative opioid consumption was significantly lower in the intravenous dexamethasone group compared with placebo (MD -6.58 mg, 95% CI -10.56 to -2.60; participants 287; studies 5). Perinerual versus intravenous dexamethasoneDuration of sensory block was significantly longer in the perineural dexamethasone group compared with intravenous by three hours (MD 3.14 hours, 95% CI 1.68 to 4.59; participants 720; studies 9). We found that postoperative pain intensity at 12 hours and 24 hours was significantly lower in the perineural dexamethasone group compared with intravenous, however, the MD did not surpass our pre-determined minimally important difference of 1.2 on the Visual Analgue Scale/Numerical Rating Scale, therefore the results are not clinically significant (MD -1.01, 95% CI -1.51 to -0.50; participants 217; studies 3) and (MD -0.77, 95% CI -1.47 to -0.08; participants 309; studies 5), respectively. There was no significant difference in severity of postoperative pain at 48 hours (MD 0.13, 95% CI -0.35 to 0.61; participants 227; studies 3). The quality of evidence is moderate for duration of sensory block and postoperative pain intensity at 24 hours, and low for the remaining outcomes. There was no difference in cumulative postoperative 24-hour opioid consumption (MD -3.87 mg, 95% CI -9.93 to 2.19; participants 242; studies 4). Incidence of severe adverse eventsFive serious adverse events were reported. One block-related event (pneumothorax) occurred in one participant in a trial comparing perineural dexamethasone and placebo; however group allocation was not reported. Four non-block-related events occurred in two trials comparing perineural dexamethasone, intravenous dexamethasone and placebo. Two participants in the placebo group required hospitalization within one week of surgery; one for a fall and one for a bowel infection. One participant in the placebo group developed Complex Regional Pain Syndrome Type I and one in the intravenous dexamethasone group developed pneumonia. The quality of evidence is very low due to the sparse number of events.

AUTHORS' CONCLUSIONS

Low- to moderate-quality evidence suggests that when used as an adjuvant to peripheral nerve block in upper limb surgery, both perineural and intravenous dexamethasone may prolong duration of sensory block and are effective in reducing postoperative pain intensity and opioid consumption. There is not enough evidence to determine the effectiveness of dexamethasone as an adjuvant to peripheral nerve block in lower limb surgeries and there is no evidence in children. The results of our review may not apply to participants at risk of dexamethasone-related adverse events for whom clinical trials would probably be unsafe.There is not enough evidence to determine the effectiveness of dexamethasone as an adjuvant to peripheral nerve block in lower limb surgeries and there is no evidence in children. The results of our review may not be apply to participants who at risk of dexamethasone-related adverse events for whom clinical trials would probably be unsafe. The nine ongoing trials registered at ClinicalTrials.gov may change the results of this review.

Chronic neuropathic pain negatively associated with employment retention of cancer survivors: evidence from a national French survey

PURPOSE

Chronic neuropathic pain (CNP) is more prevalent among cancer survivors than among the general population. This study aims to investigate the role of CNP on job retention among cancer survivors, 5 years after diagnosis.

METHODS

In 2015, 2009 individuals diagnosed with cancer in 2010 were interviewed in the French national survey VIe après le CANcer. Logistic regression investigated the relationship between CNP-measured using the seven-item Douleur Neuropathique 4 (DN4) questionnaire-and employment.

RESULTS

Nine hundred sixty-nine individuals were aged 18-54 and employed at diagnosis and therefore were included. Eighty-two percent were still employed in 2015, 26% had fewer working hours than before diagnosis, and 55% had the same working hours. Thirty percent reported CNP 5 years after diagnosis. These cancer survivors were less likely to be employed in 2015 than those without CNP and, if employed, were more likely to work fewer hours. After adjustment for gender, medical variables (adverse cancer event, prognosis, chemotherapy, and comorbidities) were found to still significantly affect employment retention in cancer survivors, as well as reporting CNP.

CONCLUSION

Improving CNP screening and management is necessary to reduce its impact on cancer survivors' professional lives.

IMPLICATIONS FOR CANCER SURVIVORS

Healthcare policy and medical cancer survivor's follow-up must take into account the importance of the substantial impact of CNP on cancer survivors' daily lives. Therefore, in order to ensure greater employment retention for cancer survivors, raising awareness of care providers about diagnosis and management of CNP is needed.

Cost of treatment of peripheral neuropathic pain with pregabalin or gabapentin in routine clinical practice: impact of their loss of exclusivity

To analyze the effect of loss of exclusivity of data on the cost of treatment of peripheral neuropathic pain (PNP) with pregabalin or gabapentin in routine clinical practice. A retrospective observational study, with electronic medical records for patients enrolled at primary care centers managed by the health care provider Badalona Serveis Assistencials, who initiated treatment of PNP with pregabalin or gabapentin. The analysis used drugs and resources prices for year 2015. The 1163 electronic medical records (pregabalin; N = 764, gabapentin; N = 399) for patients (62.2% women) with a mean (standard deviation) age of 59.2 (14.7) years were analyzed. Treatment duration was slightly shorter with pregabalin than with gabapentin (5.2 vs 5.5 months; P = 0.124), with mean doses of 227.4 (178.6) mg and 900.0 (443.4) mg, respectively. The average study drug cost per patient was higher for pregabalin than for gabapentin; €214.6 (206.3) vs €157.4 (181.9), P < 0.001, although the cost of concomitant analgesic medication was lower; €176.5 (271.8) vs €306.7 (529.2), P < 0.001. The adjusted average total cost per patient was lower in those treated with pregabalin than in those treated with gabapentin; €2,413 (2119-2708) vs €3201 (2806-3.597); P = 0.002, owing to significantly lower health care costs; €1307 (1247-1367) vs €1538 (1458-1618), P < 0.001, and also non-health care costs; €1106 (819-1393) vs €1663 (1279-2048), P = 0.023, that was caused by a significantly lower use of concomitant medication, fewer medical visits to primary care, and fewer days of sick leave. After loss of exclusivity of both drugs, pregabalin continued to show lower health care and non-health care costs than gabapentin in the treatment of PNP in routine clinical practice.

Burden of illness associated with peripheral and central neuropathic pain among adults seeking treatment in the United States: a patient-centered evaluation

Objective

The aim of this study was to evaluate patient-reported burden associated with peripheral and central neuropathic pain (NeP) by pain severity and NeP condition.

Design

Six hundred twenty-four subjects with one of six NeP conditions were recruited during routine office visits. Subjects consented to retrospective chart review and completed a one-time questionnaire (including EuroQol-5 dimensions, 12-item Short-Form Health Survey, Brief Pain Inventory-Short Form, Medical Outcomes Study Sleep Scale, Hospital Anxiety and Depression Scale, and demographic and clinical characteristics). Pain severity scores were used to stratify subjects by mild, moderate, and severe pain. Summary statistics and frequency distributions were calculated. Differences by severity level were compared using Kruskal–Wallis (continuous variables) and chi-square or Fisher's exact test (categorical variables). Effect size was computed with Cohen's d (mild vs severe).

Results

Subjects' mean age was 55.5. The majority (80.8%) had moderate or severe pain. Patient-reported outcomes (health status, physical and mental health, pain interference with function, sleep, anxiety, and depression) were significantly worse among subjects with greater pain severity (all P < 0.0001). Severe pain subjects were negatively impacted by ≥30% in each outcome compared with mild pain subjects; standardized effect size was moderate for anxiety (0.59) and large (>0.95) for all others. The observed burden was most substantial among chronic low back pain-NeP, although the pattern of disease burden was similar across the six NeP conditions.

Conclusions

Subjects across NeP conditions exhibited high pain levels, which were significantly associated with poor function, compromised health status and sleep, and increased anxiety and depression. Results indicate substantial patient burden across broad NeP, particularly among subjects with severe pain.

Adding pregabalin or gabapentin for the management of community-treated patients with painful diabetic peripheral neuropathy: a comparative cost analysis

BACKGROUND AND OBJECTIVE

Painful diabetic peripheral neuropathy (pDPN) is a highly prevalent complication of diabetes mellitus, which is associated with substantial costs to society and national health systems. This economic impact varies depending on the therapeutic management provided to patients. The objective of this study was to compare healthcare resource utilization and costs among pDPN patients newly treated with pregabalin or gabapentin in routine medical practice.

METHODS

We performed a retrospective medical records study of pDPN patients newly treated with pregabalin or gabapentin as an add-on therapy who are covered by the Badalona Serveis Assistencials (BSA) health plan, a healthcare provider in Spain, from 2006 to 2009. Healthcare resource utilization and days off work were assessed. The societal perspective was used to estimate costs.

RESULTS

Three hundred and ninety-five records were eligible for analysis: 227 (57.5%) included pregabalin and 168 (42.5%) gabapentin. Mean (standard deviation) concomitant use of analgesics throughout the study was higher in the gabapentin cohort [3.9 (2.2) vs. 3.1 (2.1); p < 0.05], mainly due to greater use of non-narcotics (78.0 vs. 71.8%; p < 0.05) and opioids (32.7 vs. 28.6%; p < 0.05). Healthcare costs accounted for 59.2% of total costs, of which 71.9% occurred in primary care, with a mean cost per patient of €2,476 (year 2010 values). Adjusted mean (95% CI) total costs were significantly lower in pregabalin-treated patients [€2,003 (1,427-2,579)] than in gabapentin-treated patients [€3,127 (2,463-3,790)] (p = 0.013), mainly due to lower healthcare costs [€1,312 (1,192-1,432) vs. €1,675 (1,537-1,814); p < 0.001].

CONCLUSIONS

Adding pregabalin to existing pDPN therapy resulted in lower total healthcare costs and lower resource utilization than resulted from adding gabapentin.

Clinical characteristics, patient-reported outcomes, and previous therapeutic management of patients with uncontrolled neuropathic pain referred to pain clinics

Background. The aim of this report was to evaluate the clinical profile and previous management of patients with uncontrolled neuropathic pain who were referred to pain clinics. Methods. We included adult patients with uncontrolled pain who had a score of ≥4 in the DN4 questionnaire. In addition to sociodemographic and clinical data, we evaluated pain levels using a visual analog scale as well as anxiety, depression, sleep, disability, and treatment satisfaction employing validated tools. Results. A total of 755 patients were included in the study. The patients were predominantly referred to pain clinics by traumatologists (34.3%) and primary care physicians (16.7%). The most common diagnoses were radiculopathy (43%) and pain of oncological origin (14.3%). The major cause for uncontrolled pain was suboptimal treatment (88%). Fifty-three percent of the patients were depressed, 43% had clinical anxiety, 50% rated their overall health as bad or very bad, and 45% noted that their disease was severely or extremely interfering with their daily activities. Conclusions. Our results showed that uncontrolled neuropathic pain is a common phenomenon among the specialties that address these clinical entities and, regardless of its etiology, uncontrolled pain is associated with a dramatic impact on patient well-being.

Effectiveness of pregabalin as monotherapy or combination therapy for neuropathic pain in patients unresponsive to previous treatments in a Spanish primary care setting

Background and Objective

Patients from a previous study of neuropathic pain (NP) in the Spanish primary care setting still had symptoms despite treatment. Subsequently, patients were treated as prescribed by their physician and followed up for 3 months. Since pregabalin has been shown to be effective in NP, including refractory cases, the objective of this study was to assess the effectiveness of pregabalin therapy in patients with NP refractory to previous treatments.

Methods

This was a post hoc analysis of pregabalin-naïve NP patients treated with pregabalin in a 3-month follow-up observational multicenter study to assess symptoms and satisfaction with treatment. Patients were evaluated with the Douleur Neuropathique en 4 questions (DN4), the Brief Pain Inventory (BPI) and the Treatment Satisfaction for Medication Questionnaire (SATMED-Q) overall satisfaction domain.

Results

1,670 patients (mean age 58 years, 59 % women), previously untreated or treated with ≥1 drug other than pregabalin, were treated with pregabalin (37 % on monotherapy). At 3 months, pain intensity and its interference with activities decreased by half (p < 0.0001), while the number of days with no or mild pain increased by a mean of 4.5 days (p < 0.0001). Treatment satisfaction increased twofold (p < 0.0001). Patients with a shorter history of pain and those with neuralgia and peripheral nerve compression syndrome (PCS) as etiologies had the highest proportion on monotherapy and showed the greatest improvements in pain-related parameters in their respective group categories.

Conclusion

Treatment with pregabalin (as monotherapy or combination therapy) provides benefits in pain and treatment satisfaction in patients with NP, including refractory cases. Shorter disease progression and neuralgia and PCS etiologies are favorable factors for pregabalin treatment response.

Sense of coherence and quality of life in older in-hospital patients without cognitive impairment--a 12 month follow-up study

BACKGROUND

The relation between sense of coherence (SOC) and quality of life (QoL) among older persons has been found in some, but not all, studies and mostly in studies with cross-sectional design. We wanted to study if SOC was associated with domains of QoL at hospitalization and one year later among persons 65 years and above without cognitive impairment.

METHOD

At hospitalization (T1) and 12 month follow-up (T2) QoL and cognitive status were assessed using the WHOQOL-BREF and the Mini-Mental State Examination. At baseline, the 13-item version of the SOC scale was used to assess coping, the Hospital Anxiety and Depression Scale (HADS) was used to assess depressive and anxiety symptoms. Level of functioning was rated using Lawton and Brody's scales for physical self-maintenance and instrumental activities of daily living (personal and instrumental ADL).

RESULTS

In total, 165 (80 men) persons with a mean age of 77.7 (SD 6.9) years were included. The proportion of people rating their overall QoL as high had decreased from T1 to T2. The mean score on QoL- physical domain had increased, while the mean score of QoL-environmental domain had decreased. In adjusted regression analyses at T1, a high level of SOC was positively associated with QoL in three of four domains, i.e. physical, psychological and environmental, but level of SOC assessed at T1 was not associated with any domain of QoL at T2. Personal ADL was associated with some domains of QOL at T1 and T2.

CONCLUSION

The SOC level was associated with older adult's QoL during hospitalization but not their QoL one year after the hospital stay.

Chronic pain in type 2 diabetic patients: a cross-sectional study in primary care setting

BACKGROUND

Although diabetes mellitus (DM) is often associated with painful neuropathic syndromes, a significant number of DM patients suffer from non-neuropathic (nociceptive) pain. Unfortunately, there is insufficient data on the epidemiology of nociceptive pain in DM patients and its effect on their quality of life.

OBJECTIVE

To characterize pain in type 2 DM patients, and assess its effect on their quality of life.

METHODS

The study population included 342 type 2 DM patients, 18 years of age and above (mean age 70.7 ± 9.7), who reported having pain. The study questionnaires included the Brief Pain Inventory (BPI), the S-LANSS scale to assess pain with neuropathic features, life impact, and socio-demographic data.

RESULTS

One hundred and fifty-five DM patients (46.5%) reported having pain of predominantly neuropathic origin. Almost 75% of patients with neuropathic pain were females, compared to 57.8% of patients with nociceptive pain (P = 0.002). More patients with neuropathic pain reported constant daily pain (57.6% vs. 42.4%, P < 0.0001), and worse pain during the night (53.3% vs. 46.7%, P = 0.045). The pain affected daily activities, walking capacity, and mood. Patients with neuropathic pain reported a greater negative effect of pain on their quality of life than those with nociceptive pain (41.0% vs. 15.3%, P < 0.0001).

CONCLUSION

The impact of neuropathic pain in DM patients is much more significant than nociceptive pain and affects their quality of life and daily function to a greater degree.

Persistent postsurgical pain

PURPOSE OF REVIEW

Persistent postsurgical pain (PPP) is an important cause of pain morbidity following surgery for almost any cause, but there is a greater evidence base for pain after cancer surgery. Historically, both patients and practitioners have struggled to recognize and accept this growing problem. This review will seek to highlight the awareness of this increasing epidemic and will discuss evidence base for diagnosis, risk factors and current strategies for prevention and treatment, especially after cancer surgery.

RECENT FINDINGS

Given the potential size of the problems of PPP, there is a relative paucity of recent data, especially as regards effective treatments. The review will synthesize current and existing evidence to give a balanced up-to-date view. There is a clear need for more high-quality randomized trials.

SUMMARY

An estimated 40,000 patients in the UK will develop PPP, of whom at least 5-10% will have severe pain. Lack of clear definition and lack of awareness have been barriers to diagnosis and access to treatment. Several risk factors associated with PPP have been identified and reduction of these factors may prevent its development. At present, there are large gaps in the evidence base and more large controlled trials are warranted.

Validity and reliability of the Japanese version of the painDETECT questionnaire: a multicenter observational study

Objectives

The aim of this study was to evaluate the validity and reliability of the Japanese version of the painDETECT questionnaire (PDQ-J).

Materials and Methods

The translation of the original PDQ into Japanese was achieved according to the published guidelines. Subsequently, a multicenter observational study was performed to evaluate the validity and reliability of PDQ-J, including 113 Japanese patients suffering from pain.

Results

Factor analysis revealed that the main component of PDQ-J comprises two determinative factors, which account for 62% of the variance observed. Moreover, PDQ-J revealed statistically significant correlation with the intensity of pain (Numerical Rating Scale), Physical Component Score, and Mental Component Score of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). The Cronbach alpha for the total score was 0.78 and for the main component was 0.80. In the analysis of test–retest method, the intraclass correlation coefficient between the two scores was 0.94.

Conclusions

We demonstrated the validity and reliability of PDQ-J. We encourage researchers and clinicians to use this tool for the assessment of patients who suffer suspected neuropathic pain.

Change in quality of life of medically hospitalized patients--a one-year follow-up study

OBJECTIVES

To examine changes in quality of life (QOL) among elderly medically hospitalized patients one year after hospitalization, and to explore factors associated with the changes.

METHODS

A one-year follow-up study included 363 (175 men) medical inpatients with age range 65-98 (mean 80.2, SD 7.5) years. Information was collected at baseline and follow-up using the WHOQOL-BREF questionnaire assessing the physical, psychological, social and environment domain of QOL as the dependent variable, and the Mini-Mental State Examination, Lawton and Brody's scales for physical self-maintenance and instrumental activities of daily living, the Hospital Anxiety and Depression scale and assistance in living as the independent variables.

RESULTS

The mean score of the physical domain of QOL had increased (mean change 0.6, SD 2.5; p < 0.01); the mean score of the environmental domain had decreased (mean change -2.1, SD 1.2; p < 0.01); and, the mean scores of the psychological and social domains of QOL were unchanged (mean change -0.2, SD 1.8 and mean change -0.1, SD 1.5, respectively) at follow-up. Improved individual QOL at a one-year follow-up was associated with improved health (cognitively, physically and emotionally) after hospitalization, and with health situation at baseline. Being in need of assistance was associated with reduced QOL.

CONCLUSION

Good cognitive, physical and emotional health at baseline and follow-up were associated with improved QOL in previously hospitalized elderly patients independent of their need for assistance in living.

Cost analysis of adding pregabalin or gabapentin to the management of community-treated patients with peripheral neuropathic pain

OBJECTIVE

To compare the cost of adding either pregabalin or gabapentin to the management of community-treated patients with peripheral neuropathic pain (PNP).

METHODS

A retrospective observational study was conducted using medical records from a Spanish health care provider claims database. Patients receiving health care for PNP, above 18 years and for which either pregabalin or gabapentin was initiated between 2006 and 2008 were included. Economic evaluation included health care resource utilization costs and costs due to sick leave.

RESULTS

A total of 1163 patients with PNP were eligible for analysis: 764 were prescribed pregabalin and 399 gabapentin in addition to current pain therapy. Mean age was 59.2 years and 62.2% were female. Concomitant use of analgesics was higher in the gabapentin cohort (3.2 vs. 2.7; P = 0.003), mainly due to non-steroidal anti-inflammatory drugs (74.9% vs. 69.5%; P = 0.018) and opioids (27.7% vs. 17.9%; P = 0.031). Adjusted total costs per patient was lower in pregabalin-treated patients (€2514 vs. €3241; P = 0.003), due to less sick leave (€1067 vs. €1633; P = 0.018) and lower health care costs (€1447 vs. €1609; P = 0.004). The higher acquisition cost of pregabalin (€351 vs. €191; P < 0.001) was largely compensated with lower costs in medical visits, physiotherapy, hospital stays and concomitant analgesics.

CONCLUSIONS

In community-treated patients with PNP, total costs were considerably less for those patients initiated with pregabalin therapy than for those patients starting gabapentin add-on therapy. The relatively higher treatment acquisition cost of pregabalin was largely compensated by the overall lower costs for the other components of health care resources and sick leave, thus reducing the economic impact on the health care provider's budget and society.

A cost-effectiveness analysis of the effect of pregabalin versus usual care in the treatment of refractory neuropathic pain in routine medical practice in Spain

OBJECTIVE

The objective of this study was to estimate the cost-effectiveness of pregabalin vs usual care (UC) in outpatients with refractory neuropathic pain (NeP), treated according to routine medical practice in primary care settings in Spain.

METHODS

Patients were extracted from a 12-week noninterventional prospective study conducted to ascertain the costs of NeP. Pairs of pregabalin-naïve patients receiving UC or pregabalin, matched by age, gender, pain intensity, and refractory to previous treatment, were selected in a 1:1 ratio. Refractory was considered a patient with actual pain (scoring >40 in a 100 mm in a pain visual analog scale) after receiving a course of a standard analgesic, at its recommended doses. Perspectives of the Spanish National Healthcare System and society were included in the analysis. Effectiveness was expressed as quality-adjusted life-year (QALY) gain. Results of the cost-effectiveness analysis were expressed as an incremental cost per QALY (ICER) gained. Probabilistic sensitivity analysis using bootstrapping techniques was also carried out.

RESULTS

A total of 160 pairs were extracted. Compared with UC, pregabalin was associated with significantly higher QALY gain; 0.0374 ± 0.0367 vs 0.0224 ± 0.0313 (P < 0.001). Despite drug acquisition costs being higher for pregabalin (€251 ± 125 vs €104 ± 121; P < 0.001), total and health care costs incurred for pregabalin were similar in both groups; €1,335 ± 1,302 vs €1,387 ± 1,489 (P = 0.587) and €529 ± 438 vs €560 ± 672 (P = 0.628), respectively, yielding a dominant ICER for both total and health care costs in the base case scenario; 95% confidence intervals, respectively, dominant to €17,268, and dominant to €6,508. Sensitivity analysis confirmed results of the basecase scenario.

CONCLUSION

This study showed that pregabalin may be cost-effective in the treatment of refractory NeP patients when compared with UC in routine medical practice in Spain.

Pain, neuropathic symptoms, and physical and mental well-being in persons with cancer

BACKGROUND

Neuropathic pain is present in at least 25-40% of people with cancer pain and is thought to be more difficult to control than other types of cancer related pain.

OBJECTIVE

The purpose of this study was to explore differences in the experience of cancer patients who describe their pain using neuropathic descriptors compared to those who do not.

METHODS

A secondary analysis of data from 234 outpatients from a large NCI designated cancer center in west, central Florida was conducted to identify differences in pain, pain interference, symptoms, health related quality of life, and depression between the two groups.

RESULTS

Patients with numbness, tingling, or electric-like sensations reported higher levels of current pain (p= .001), pain at its worst (p= .001), pain on average (p= .019), pain at its least (p= .008), and pain interference (p< .001). They reported problems with dizziness/lightheadedness significantly more often (p=.004) and also reported more severe problems with concentration (p=.047), poorer physical (p=.019) and mental health (p=.024), although no differences in depressive symptoms were found.

CONCLUSIONS

The results of this study indicate that cancer patients with numbness, tingling, or electric-like sensations have significantly higher levels of pain and pain interference, and lower health related quality of life than do patients without these symptoms.

IMPLICATIONS FOR PRACTICE

These results highlight the ongoing need for research evaluating methods of treating neuropathic pain; education regarding assessment and management of neuropathic pain; and aggressive efforts to relieve neuropathic pain in oncology settings.

[Prevalence of neuropathic pain according to the NP4 test in primary care]

BACKGROUND

Primary Care Physicians are usually the first to see patients with neuropathic pain. The aim of this study is to assess the prevalence of neuropathic pain, its therapeutic management, and to clinically characterize these patients.

MATERIAL AND METHODS

An epidemiological, observational, cross-sectional study was carried out in Spanish Primary Care settings. The first 25 patients older than 18 years with any type of pain (a total of 16,115) were registered, and the first 5 with a high neuropathic pain component according to the NP4 test, and was clinically confirmed (n= 3,836) were included in the study. Pain intensity and impact on daily activities, as well as overall satisfaction with treatment were assessed.

RESULTS

A total of 45.7% of patients had neuropathic pain according to NP4 test. The median age was 59 years, and 60% were women. Patients took a mean of 2.4 drugs, with NSAIDs (53%) and non-opioid analgesics (51%) being the most common. The scores for Pain intensity and interference in daily activities were both 6.2. The overall opinion of the SATMED-Q test was 47.3/100, which was 1.4 points lower than the standardised score according to Spanish population.

CONCLUSIONS

Neuropathic pain according to NP4 test is highly prevalent in Spanish Primary Care settings. The management of these patients with NSAIDs and non-opioid analgesics is not appropriate, as they are not recommended for this kind of pain. Although they were being treated with more than 2 analgesics, they still referred to high pain intensity, interference in daily activities, and a low general opinion of the treatment.

The specific disease burden of neuropathic pain: results of a French nationwide survey

We report the first nationwide survey of the impact of neuropathic pain, as opposed to nonneuropathic pain, on quality of life and health care utilization in the French general population. A postal questionnaire was sent to a representative sample of 4554 respondents from an initial nationwide survey of 30,155 subjects with or without chronic pain. It included pain characteristics (Neuropathic Pain Symptom Inventory, DN4), quality of life (Medical Outcomes Short Form 12, SF-12), sleep, anxiety/depressive symptoms (Hospital Anxiety and Depression Scale) and health care utilization. In total, 3899 (85.6%) questionnaires were returned, 3816 (97.9%) could be assessed and 3165 subjects (82.9%) confirmed their pain status. Subjects reporting pain and neuropathic characteristics based on the DN4 displayed a higher degree of impairment of all dimensions relating to quality of life and sleep and had higher anxiety/depression scores than those reporting pain without neuropathic characteristics and those without pain (P<.01). They also made greater use of health care facilities, particularly as concerned neurological treatments and visits to neurologists (21% vs 9%; P<.01). Multivariate analyses showed that the neuropathic characteristics of pain made an independent contribution to quality-of-life impairment (P<.0001 and P=.0005 for the physical and mental scores of the SF-12 respectively). Our study indicates that the disease burden of chronic pain depends on the nature of the pain, independently of its intensity and duration.

Costs and health resources utilization following switching to pregabalin in individuals with gabapentin-refractory neuropathic pain: a post hoc analysis

PURPOSE

To analyze the changes in pain severity and associated costs resulting from resource utilization and reduced productivity in patients with gabapentin-refractory peripheral neuropathic pain who switched to pregabalin therapy in primary care settings in Spain.

PATIENTS AND METHODS

This is a post hoc analysis of a 12-week, multicentre, noninterventional cost-of-illness study. Patients were included in the study if they were over 18 years of age and had a diagnosis of chronic, treatment-refractory peripheral neuropathic pain. The analysis included all pregabalin-naïve patients who had previously shown an inadequate response to gabapentin and switched to pregabalin. Severity of pain before and after treatment with pregabalin, alone or as an add-on therapy, was assessed using the Short-Form McGill Pain Questionnaire (SF-MPQ) and its related visual analogue scale (VA). Healthcare resource utilization, productivity (including lost-workday equivalents [LWDE]), and related costs were assessed at baseline and after pregabalin treatment.

RESULTS

A total of 174 patients switched to pregabalin had significant and clinically relevant reductions in pain severity (mean [SD] change on SF-MPQ VA scale, -31.9 [22.1]; P < 0.05 vs. baseline; effect size, 1.87). Reduction in pain was similar with both pregabalin monotherapy and add-on therapy. Significant reductions in healthcare resource utilization (concomitant drug use [in pregabalin add-on group], ancillary tests, and unscheduled medical visits) were observed at the end of trial. Additionally, there were substantial improvements in productivity, including a reduction in the number of LWDE following pregabalin treatment (-18.9 [26.0]; P < 0.0001). These changes correlated with substantial reductions in both direct (-652.9 ± 1622.4 €; P < 0.0001) and indirect healthcare costs (-851.6 [1259.6] €; P < 0.0001).

CONCLUSIONS

The cost of care in patients with gabapentin-refractory peripheral neuropathic pain appeared to be significantly reduced after switching to pregabalin treatment, alone or in combination with other analgesic drugs, in a real-life setting.

[Predictive factors and prevention of chronic postoperative pelvic and perineal pain]

INTRODUCTION

Chronic postoperative pain has been defined as pain arising after a surgical operation, present for at least 2 months, with no organic (active cancer or chronic infection) or preexisting cause. The purpose of this article is to review the risk factors and prevention of chronic postoperative pelvic and perineal pain.

MATERIAL AND METHODS

A review of the literature was performed by searching PubMed for articles on risk factors and prevention of chronic postoperative pelvic and perineal pain.

RESULTS

Chronic postoperative pain is frequent, disabling and represent a high cost to the community. This pain is generated by variable and complex interactions between the surgical procedure (the operated zone, perioperative management, the disease requiring the operative procedure) and the patient (age, gender, genetics, concomitant diseases, personal history). The multifactorial nature of chronic postoperative pain suggests the need for multidisciplinary management with prevention and reduction of the main risk factors. Similarly, appropriate management of acute postoperative pain has a major impact on the risk of chronic pain.

CONCLUSION

A good knowledge of the risk factors and appropriate prevention can decrease the incidence and consequences of chronic postoperative pain.

Development and preliminary validation of the NePIQoL: a quality-of-life measure for neuropathic pain

Neuropathic pain is frequently associated with negative effects on quality of life (QoL), affecting physical, social, and psychological functioning. Of many existing scales used to measure QoL, none have been validated in a neuropathic pain patient population. This study reports on the development and preliminary psychometric evaluation of the Neuropathic Pain Impact on Quality-of-Life questionnaire (NePIQoL), a measure to assess QoL in neuropathic pain. In Phase I, focus groups with 27 patients and a panel of experts identified QoL issues for inclusion in the measure. Initial items (152) and response categories were pretested using cognitive interviewing (18 patients). Following this, the number of items was reduced to 91. In Phase II, the 91-item version of the NePIQoL was administered to a further 112 patients, poorly performing items were identified, and internal consistency was examined. In Phase III, the revised NePIQoL was administered to a further 110 patients on two occasions to examine validity and test-retest reliability. Qualitative and quantitative pretesting led to extensive revision, resulting in a final measure of 42 items. Finally, Phase IV tested the concurrent validity and responsiveness of the NePIQoL. The authors conclude that the NePIQoL is an acceptable, patient-derived, neuropathic pain-specific measure with evidence of reliability, validity, and temporal stability.

Neuropathic pain: quality-of-life impact, costs and cost effectiveness of therapy

A number of different diseases or injuries can damage the central or peripheral nervous system and produce neuropathic pain (NP), which seems to be more difficult to treat than many other types of chronic pain. As a group, patients with NP have greater medical co-morbidity burden than age- and sex-adjusted controls, which makes determining the humanistic and economic burden attributable to NP challenging. Health-related quality of life (HR-QOL) is substantially impaired among patients with NP. Patients describe pain-related interference in multiple HR-QOL and functional domains, as well as reduced ability to work and reduced mobility due to their pain. In addition, the spouses of NP patients have been shown to experience adverse social consequences related to NP. In randomized controlled trials, several medications have been shown to improve various measures of HR-QOL. Changes in HR-QOL appear to be tightly linked to pain relief, but not to the development of adverse effects. However, in cross-sectional studies, many patients continue to have moderate or severe pain and markedly impaired HR-QOL, despite taking medications prescribed for NP. The quality of NP treatment appears to be poor, with few patients receiving recommended medications in efficacious dosages. The substantial costs to society of NP derive from direct medical costs, loss of the ability to work, loss of caregivers' ability to work and possibly greater need for institutionalization or other living assistance. No single study has measured all of these costs to society for chronic NP. The cost effectiveness of various interventions for the treatment or prevention of different types of NP has been assessed in several different studies. The most-studied diseases are post-herpetic neuralgia and painful diabetic neuropathy, for which tricyclic antidepressants (both amitriptyline and desipramine) have been found to be either cost effective or dominant relative to other strategies. Increasing the use of cost-effective therapies such as tricyclic antidepressants for post-herpetic neuralgia and painful diabetic neuropathy may improve the HR-QOL of patients and decrease societal costs. Head-to-head clinical trials comparing NP therapies are needed to help assess the relative clinical efficacy of treatments, ideally using HR-QOL and utility outcomes. The full costs to society of NP, including productivity loss costs, have not been determined for chronic NP. Improved relative efficacy, utility and cost estimates would facilitate future cost-effectiveness research in NP.