Effectiveness of pregabalin for the treatment of chronic low back pain with accompanying lower limb pain (neuropathic component): a non-interventional study in Japan

Acute back pain: The role of medication, physical medicine and rehabilitation: WFNS spine committee recommendations

Objectives

To formulate the most current, evidence-based recommendations for the role of medication, physical medicine, and rehabilitation in the management of acute low back pain lasting <4 weeks.

Methods

A systematic literature search in PubMed and Google Scholar databases was performed from 2012 to 2022 using the search terms "acute low back pain," "drugs," "bed rest," "physical medicine," rehabilitation." Standardized screening criteria resulted in a total of 39 articles that were analyzed, including 16 RCTs, 8 prospective studies, 6 retrospective studies, and 9 systematic reviews. This up-to-date information was reviewed and presented at two separate meetings of the World Federation of Neurosurgical Societies (WFNS) Spine Committee. Two rounds of the Delphi method were utilized to vote on the statements and arrive at a positive or negative consensus.

Results and conclusion

The WFNS Spine Committee finalized twelve recommendation guidelines on the role of medication, physical medicine and rehabilitation in the management of acute LBP. We advocate for a uniform approach to the treatment of these patients, including proper patient education and utilizing drugs with proven efficacy and minimal side effects. First-line pharmacologic agents are acetaminophen and NSAIDs; muscle relaxants can be used for spasms and pain reduction, and opioids should be minimized. Continued activity, rather than bed rest, is recommended, and lumbar spine orthotics may be used to reduce pain and augment functional status. Thermotherapy, cryotherapy, TENs, spinal manipulative therapy, and acupuncture may all be used as adjuncts to improve acute LBP.

Efficacy and Safety of Add-on Mirogabalin to NSAIDs in Lumbar Spinal Stenosis with Peripheral Neuropathic Pain: A Randomized, Open-Label Study

INTRODUCTION

In Japan, conservative therapy for patients with lumbar spinal stenosis (LSS) includes non-steroidal anti-inflammatory drugs (NSAIDs), prostaglandin E1, tramadol, physical/exercise therapy, and nerve blocks. Mirogabalin, a selective oral α2δ ligand, is approved for treating peripheral neuropathic pain, though data regarding visual analog scores (VAS) for pain in patients with LSS are limited. We investigated the efficacy and safety of mirogabalin as an add-on treatment in patients with LSS taking NSAIDs compared with patients taking NSAIDs only.

METHODS

This multicenter, randomized, open-label study (MiroTAS) was conducted at 32 centers in Japan between June 2020 and October 2021. Patients were randomly assigned to mirogabalin and NSAIDs or NSAIDs alone in a 1:1 ratio. NSAIDs were administered according to their Japanese package inserts; mirogabalin was administered based on renal function [creatinine clearance (CrCL) ≥ 60 mL/min, 5 mg twice daily (BID) in Weeks 1-2, 10 mg BID in Weeks 3-4, and 15 or 10 mg BID after Week 5; CrCL 30 to < 60 mL/min, 2.5 mg BID Weeks 1-2, 5 mg BID Weeks 3-4, and 7.5 or 5 mg BID after Week 5]. The primary endpoint was the change in VAS score for leg pain from baseline to Week 12. Secondary endpoints were quality of life, evaluated using the EuroQol five-dimensional descriptive system (EQ-5D-5L) (at baseline and Week 12) and Patient Global Impression of Change (PGIC) (at Week 12), and safety. Change in VAS score at Week 12 was calculated using a linear mixed model for repeated measures. The safety endpoints were treatment-emergent adverse events (TEAEs) and adverse drug reactions.

RESULTS

In total, 220 patients who met the eligibility criteria were enrolled. In the mirogabalin and NSAIDs and NSAIDs groups, mean ages (67.8 vs. 70.9 years), proportions of female patients (54.5% vs. 49.0%), mean body weights (63.9 vs. 62.0 kg), mean CrCL values (81.5 vs. 70.7 mL/min), proportions of patients with CrCL 30 to < 60 mL/min (27.3% vs. 33.7%), mean VAS scores (63.8 vs. 62.8 mm), and proportions of patients with VAS score ≥ 60 (53.6% vs. 52.9%) at enrollment were similar. The median durations of LSS were 9.0 and 11.0 months and the spine pain DETECT questionnaire (SPDQ) scores were 6.8 and 7.8, respectively. The least square (LS) mean change in VAS score from baseline to Week 12 was - 24.1 mm in the mirogabalin and NSAIDs group and - 14.2 mm in the NSAIDs group (both P < 0.0001 vs. baseline). The difference in LS mean was - 9.9 [95% confidence interval (CI), - 18.0, - 1.8] (P = 0.0174). The improvement in EQ-5D-5L score at Week 12 was significantly greater in the mirogabalin and NSAIDs group versus the NSAIDs group [mean difference, 0.0529 (95% CI, 0.0036, 0.1022), P = 0.0357]. At Week 12, the proportions of patients with PGIC scores ≤ 3 and ≤ 2 were higher in the mirogabalin and NSAIDs group vs. the NSAIDs group (76.2% vs. 50.0%, P = 0.0006, and 47.6% vs. 32.4%, P = 0.0523). In the mirogabalin and NSAIDs group, the incidences of TEAEs and adverse drug reactions were 60.9% and 57.3%, respectively, and the most common TEAEs were somnolence (30.0%) and dizziness (25.5%).

CONCLUSIONS

The addition of mirogabalin to NSAIDs improved VAS, EQ-5D-5L, and PGIC. The main TEAEs were somnolence and dizziness. The addition of mirogabalin to NSAIDs improved peripheral neuropathic pain associated with LSS and raised no new safety concerns.

TRIAL REGISTRATION

Japan Registry of Clinical Trials (jRCTs021200007).

Efficacy and Safety of Pregabalin Prolonged Release-Etoricoxib Combination Compared to Etoricoxib for Chronic Low Back Pain: Phase 3, Randomized Study

INTRODUCTION

Currently available treatments for chronic lower back pain (CLBP) do not adequately address both nociceptive and neuropathic components of pain. We evaluated efficacy and safety of fixed-dose combination (FDC) of low-dose pregabalin prolonged release 75 mg-etoricoxib 60 mg to address both pain components.

METHODS

This randomized phase 3 trial conducted at 12 centres across India evaluated efficacy (based on mean change in numeric rating scale [NRS], Roland-Morris disability questionnaire [RDQ], visual analogue scale [VAS], patient global impression of improvement [PGI-I], clinical global impression of improvement [CGI-I] and rescue medication consumption) and safety of FDC in comparison to etoricoxib alone in adult patients with CLBP. Treatment duration was 8 weeks.

RESULTS

Of the 371 patients screened, 319 were randomized and considered for efficacy and safety analysis. Both treatment groups had no significant difference in terms of demography and baseline disease characteristics. Significantly better outcomes with FDC compared to etoricoxib were observed at week 4 onwards. At week 8, both groups showed significant reduction in mean NRS score from baseline (- 4.00 ± 1.65 in FDC; - 2.92 ± 1.59 in etoricoxib) with mean NRS score being significantly less in the FDC group compared to etoricoxib group (3.26 ± 1.56 vs 4.31 ± 1.56; p < 0.0001). The FDC was more effective than etoricoxib in terms of significantly greater reduction in RDQ score (- 9.28 ± 4.48 vs - 6.78 ± 4.34; p < 0.0001) and VAS score (- 37.66 ± 18.7 vs - 28.50 ± 16.31; p < 0.0001) at week 8. The FDC was also better in terms of significantly more patients reporting their condition as 'very much better' (36.9% vs 5.0%; p < 0.0001) and clinicians reporting patient's condition as 'very much improved' (36.3% vs 5.7%; p < 0.0001). Overall, study medications were well tolerated.

CONCLUSION

FDC of pregabalin and etoricoxib provided significant benefits in reducing pain and improving functional status compared with etoricoxib alone in patients with CLBP. Pregabalin prolonged release-etoricoxib FDC could be one of the treatment options for early and sustained pain relief and improvement in quality-of-life in treating CLBP as it addresses both neuropathic and nociceptive components of pain.

TRIAL REGISTRATION

CTRI/2018/10/015886.

Direct and Indirect Pathways for Health-Related Quality of Life Change from Pain Improvement in Neuropathic Pain Patients with Spine Diseases: Path Analysis with Structural Equation Modeling Using Non-Interventional Study Results of Pregabalin

Background

Chronic low back pain or chronic cervical pain often has a neuropathic pain (NeP) component and patients with these conditions complain of sleep deprivation, loss of physical function, and reduced productivity due to pain. The objective of this study was to clarify the pathway by which pain, sleep disturbance due to pain, and physical function status influence QOL measures in chronic low back pain patients with NeP associated with lumbar spine diseases (CLBP-NeP) and in chronic cervical pain patients with NeP associated with cervical spine diseases (CCP-NeP).

Methods

A model assuming pain numeric rating scale (NRS), pain-related sleep interference scale (PRSIS), and functional indices (Roland Morris Disability Questionnaire [RMDQ], Neck Disability index [NDI]) as factors that can affect outcomes such as QOL (calculated using EuroQoL 5 Dimensions (EQ-5D)), the Patient Global Impression of Change (PGIC), and the Clinical Global Impression of Change (CGIC) was developed using structural equation modeling.

Results

Overall trends were frequently observed in both patients with CLBP-NeP and CCP-NeP. Pain NRS had the largest comprehensive direct impact on QOL based on EQ-5D and an overall impression of changing symptoms. The effects of pain NRS on each outcome were largely due to direct pain-related effects; however, for EQ-5D, an indirect effect via functional improvement was the primary factor.

Conclusion

Although the results of this study suggest that the indirect functional improvement of pain relief may not be recognized as a significant component of therapeutic effects by both physicians and patients, the pain-relieving intervention contributes directly to improvement of patients' overall QOL and also indirectly via functional improvement in Japanese primary care settings. Accordingly, to achieve the therapeutic goal for patients with NeP and minimize the impact of pain burden, our findings indicate that pain relief interventions are also crucial from the perspective of the patient's HRQOL.

Effectiveness of Pregabalin Treatment for Neuropathic Pain in Patients with Spine Diseases: A Pooled Analysis of Two Multicenter Observational Studies in Japan

Purpose

Neuropathic pain (NeP) is common among patients with chronic pain associated with spine diseases. Practical effectiveness of pregabalin, one of the first-line treatments for NeP, has not been evaluated in an entire population of patients with spine diseases, including various pathophysiological conditions. This pooled analysis aimed to evaluate the therapeutic value of pregabalin for chronic pain with NeP component in patients with spine diseases in routine primary care settings.

Patients and Methods

We pooled data from two 8-week prospective observational cohort studies for patients with chronic low back pain with accompanying lower limb pain (NeP component), and patients with chronic cervical pain and accompanying upper limb radiating pain (NeP component) in routine primary care settings in Japan. For both studies, patients were treated for 8 weeks with pregabalin (alone/with other analgesics) or usual care with conventional analgesics (eg, non-steroidal anti-inflammatory drugs). Changes in pain numerical rating scale (NRS), Pain-Related Sleep Interference Scale (PRSIS), and EuroQol 5-dimension 5-level (EQ-5D-5L) scores from baseline to week 8 were summarized and compared between the pregabalin and usual care groups, and also for subgroups of primary diagnosis. Safety was evaluated by adverse events (AEs) in the pregabalin group.

Results

The pooled dataset comprised 700 patients (pregabalin group: 302; usual care group: 398). All patient-reported outcomes (PRO) scores significantly improved from baseline to week 8 in the pregabalin than in the usual care group (NRS: P<0.0001; PRSIS: P<0.0001, and EQ-5D-5L: P=0.0006). Overall, all three PRO measures showed greater improvement in the pregabalin than in the usual care group, irrespective of the primary diagnosis. AEs were reported in 36.1% of the pregabalin group.

Conclusion

This analysis suggested multi-faceted effectiveness of treatment with pregabalin from the patient’s perspectives under a “real-world” practice in all patients with chronic NeP from various spine diseases.

Therapeutic Effect of Mirogabalin on Peripheral Neuropathic Pain due to Lumbar Spine Disease

Study Design

Retrospective study.

Purpose

This study aims to evaluate the effectiveness of mirogabalin in treatment of peripheral neuropathic pain due to lumbar spine disease.

Overview of Literature

Mirogabalin is a novel selective ligand for the α2δ subunit of voltage-gated Ca channels.

Methods

Between April and December 2019, we used mirogabalin to treat 60 consecutive patients (mean age, 67.6 years) with leg symptoms due to lumbar disease. The treatment outcome after 8 weeks of mirogabalin therapy was evaluated by comparing the preand post-administration Numerical Rating Scale (NRS) for leg symptoms and sleep disturbance, the NRS and Roland–Morris Disability Questionnaire for low back pain (LBP), and the quality of life (QOL) score (based on EuroQol five-dimension five-level scale).

Results

Mirogabalin treatment was stopped at less than eight weeks in eight patients. The remaining 52 patients for evaluation were divided as group 1 (17 patients who presented with leg symptoms that lasted for less than 3 months) and group 2 (35 patients with leg symptoms that lasted longer than 3 months). The leg symptoms and LBP in both groups significantly improved at 4 and 8 weeks of treatment, and sleep disturbance and QOL were improved at 8 weeks as well. Compared to group 2, the pretreatment leg symptoms and QOL were significantly worse in group 1, and their improvement after 8 weeks of mirogabalin treatment was significantly better (p<0.05). Of the 60 original patients, 17 suffered adverse effects, which were mild in 16 patients and required treatment cessation due to excessive weight gain in one patient.

Conclusions

We have validated the effect of mirogabalin on neuropathic pain due to lumbar spine disease, which has effectively addressed the associated leg symptoms, LBP, and sleep disturbance.

Measuring the impact of chronic low back pain on everyday functioning: content validity of the Roland Morris disability questionnaire

BACKGROUND

Robust outcome measures are needed to assess and monitor the impact of chronic low back pain (CLBP) on physical functioning. The Roland Morris Disability Questionnaire (RMDQ) is a well-established measure designed to capture the impacts of back pain on everyday functioning, with a particular emphasis on physical functioning. It has documented evaluation of psychometric properties. However, there is no documented qualitative evidence to confirm the content validity of the tool, nor have changes made for electronic administration been debriefed in participants with CLBP.

METHODS

In-depth, semi-structured, concept elicitation and cognitive debriefing interviews were conducted with 23 US participants with confirmed CLBP. Interviews allowed participants to describe the impact of CLBP on their day-to-day functioning and discuss comprehension and suitability of the RMDQ. Interviews were transcribed verbatim and analyzed using thematic analysis.

RESULTS

Concept elicitation and cognitive debriefing revealed the substantial burden associated with CLBP, highlighting 15 key areas of functional impact. These were grouped into overarching themes of mobility (walking, stairs, sitting/standing, bending/kneeling, lifting, lying down), activities (chores/housework, dressing, washing, driving, work) and other (relationships/socializing, mood, sleep, appetite), which are consistent with those evaluated within the RMDQ. All participants found the RMDQ to be relevant with most reporting that the instructions, recall period, and response options were suitable. A few suggested minor changes, however, none were consistent or necessary to support content validity. Updates to the measure for electronic administration and to clarify the response options were well received.

CONCLUSION

The qualitative data from individuals with CLBP confirmed that the RMDQ has content validity and, alongside documented psychometric evidence, supports the use of the RMDQ as a reliable and valid tool to assess the impact of CLBP on physical functioning.

A comparative study of aceclofenac versus etoricoxib in the management of acute low back pain in a tertiary care hospital

Background

The aim of management of acute low back pain is to alleviate the pain quickly and improve functional ability. Non-steroidal anti-inflammatory drugs are the first line of treatment. The challenge lies in deciding which NSAIDs will provide greater symptomatic relief, while also being cost-effective.

Objective

To compare the effectiveness of aceclofenac and etoricoxib in the management of acute low back pain.

Methods

This prospective, open label, observational study was conducted at a tertiary care hospital. Patients over 18 years of age and presenting with low back pain of less than 6 weeks duration were enrolled in the study. Fifty patients with non-specific low back pain were randomized into two groups: Group A received aceclofenac (2 mg/kg) twice a day and Group B received etoricoxib (1 mg/kg) twice a day for 1 week. The Numerical Rating Scale (NRS) and Oswestry Low Back Disability Index (ODI) determined the clinically meaningful outcomes.

Results

The decrease in pain intensity in Group A was 52.27%, while in Group B it was 62.53%. However, the decrease in pain scores between the groups was not statistically significant (p = .3795). Improvement in functional ability in Group A and Group B was 57.01% and 61.48%, respectively. However, this improvement between the groups was not statistically significant (p > .999) at the end of 1 week. The average cost-effectiveness ratio indicated that etoricoxib was the dominant treatment over aceclofenac. Therefore, etoricoxib was found to be the cost-effective option for short-term pain relief in acute low back pain for 1 week.

Conclusion

Both aceclofenac and etoricoxib were clinically effective in reducing the pain intensity and in improving functional ability. However, etoricoxib was found to be the cost-effective intervention.

A Cost-Effectiveness Analysis Of Pregabalin For The Treatment Of Patients With Chronic Cervical Pain With A Neuropathic Component In Japan

Purpose

To evaluate the cost-effectiveness of pregabalin versus other analgesics among patients with chronic cervical pain with neuropathic components during routine clinical practice in Japan.

Patients and methods

The analysis considered patients with chronic cervical pain with a neuropathic pain component (radiating pain to the upper limb) and who were treated with pregabalin with or without other analgesics (pregabalin-containing treatments) or other analgesics alone (usual care) for 8 weeks. Other analgesics included non-steroidal anti-inflammatory drugs (NSAIDs), weak opioids, antidepressants, and antiepileptic drugs. A Markov cohort simulation model was constructed to estimate costs and effectiveness (in terms of quality-adjusted life-years, QALYs) of each treatment over a 12-month time horizon. In the model, patients transitioned among three states of pain severity (no/mild, moderate, and severe). Data were derived from a previous observational study (pregabalin-containing treatments, n = 138; usual care, n = 211). Cost inputs included medical costs and productivity losses. QALYs were calculated using the EuroQol five-dimensional, five-level questionnaire. The cost-effectiveness was evaluated using incremental cost-effectiveness ratios (ICERs). Sensitivity analyses were conducted to assess the robustness of results.

Results

From the payer's perspective, pregabalin-containing treatments were more costly (JPY 61,779 versus JPY 26,428) but also more effective (0.763 QALYs versus 0.727 QALYs) than the usual care, with an ICER of JPY 970,314 per QALY gained. From the societal perspective, which also included productivity losses, the ICER reduced to JPY 458,307 per QALY gained. One-way sensitivity analyses demonstrated the robustness of the results. Given a hypothetical threshold value of one additional QALY of JPY 5,000,000, the probability of pregabalin-containing treatments being cost-effective was 100%.

Conclusion

Compared with using other analgesics alone, the use of pregabalin, alone or in addition to other analgesics, was cost-effective for the treatment of chronic cervical pain with a neuropathic pain component in Japan.

Effectiveness of pregabalin for treatment of chronic cervical radiculopathy with upper limb radiating pain: an 8-week, multicenter prospective observational study in Japanese primary care settings

Background: Despite high prevalence of chronic neck pain in Japan and the negative impact pain has on patient’s quality of life (QoL), the therapeutic value of pregabalin for chronic neck pain with a neuropathic pain (NeP) component has not been assessed in a typical Japanese health care setting.

Methods: An 8-week, non-interventional, multicenter, observational study of Japanese adults (≥20 years) with chronic refractory cervical pain including a NeP element (for ≥12 weeks) and sleep disturbance on the Pain-Related Sleep-Interference Scale (PRSIS) ≥1 (from 0 “does not interfere with sleep” to 10 “completely interferes”). Patients received either usual care with conventional analgesics or pregabalin (150–600 mg/day) for 8 weeks. “Usual care” with analgesics or other treatment(s) was determined based on physician’s best clinical judgment. Primary endpoint was change from baseline to week 8 in PRSIS. Secondary endpoints included: change from baseline to week 4 in PRSIS, and to week 4 and 8 in pain Numerical Rating Scale (NRS; from 0 “no pain” to 10 “worst possible pain”), and on the Neck Disability Index (NDI). Other assessments of QoL were undertaken. Safety was monitored.

Results: Overall, 369 patients received pregabalin (n=145) or usual care (n=224). The median (range) dose of pregabalin was 49.6 (25.0–251.5) mg/day. Least-squares mean change in PRSIS from baseline to week 8 favored pregabalin (–1.167 vs –0.269; treatment difference –0.898 [95% CI –1.262, –0.535], P<0.001). Similar observations were seen at week 4 in favor of pregabalin versus usual care (P<0.001). Pregabalin significantly improved pain NRS and NDI scores at weeks 4 and 8 (all P<0.001). Improvements in QoL versus usual care were also observed. Pregabalin was generally well tolerated.

Conclusion: In this open-label study, pregabalin improved PRSIS and resulted in clinically meaningful reductions in pain in Japanese patients with NeP associated with chronic cervical pain.

ClinicalTrials.gov identifier: NCT02868359.

Efficacy of 50 mg pregabalin for prevention of postoperative neuropathic pain after video-assisted thoracoscopic surgery and thoracotomy: a 3-month prospective randomized controlled trial

Background

This study analyzed the preventive effect of 50 mg/day pregabalin on postoperative neuropathic pain, and any additional benefits related to sleep and respiratory function.

Methods

This prospective randomized controlled study included lung resection patients 20-89 years of age. Patients were randomly assigned to the treatment (pregabalin; initial dose, 50 mg/day) or control (non-steroidal anti-inflammatory drugs) group. Pregabalin patients received non-steroidal anti-inflammatory drugs and pregabalin (25 mg, twice daily) from the second postoperative day. Pain scores, neuropathic pain, analgesic use, respiratory function, and insomnia scale scores for 3 months after surgery were evaluated.

Results

This study included 46 patients who received pregabalin and 46 control patients. Pregabalin patients had significantly less postoperative neuropathic pain than control patients (19.6% vs. 41.3%; P=0.0404), and their duration of neuropathic pain was significantly shorter (30 vs. 90 days; P=0.024). The onset of postoperative neuropathic pain, insomnia scale scores, and respiratory function were similar between groups. No pregabalin-related adverse events were reported.

Conclusions

Pregabalin (50 mg/day) had a significant preventive effect on postoperative neuropathic pain after thoracic surgery, without side effects. Early postoperative administration of pregabalin would help prevent neuropathic pain and provide better pain control after thoracic surgery.

Is Pregabalin Effective Against Acute Lumbar Radicular Pain ?

Introduction

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the first-line treatment for acute lumbar radicular pain accompanying lumbar disc herniation (LDH), but their effects are minimal. The purpose of this study was to evaluate the efficacy and safety of pregabalin (PGB) as an alternative therapy for this condition.

Methods

Patients with acute lumbar radicular pain accompanying LDH were randomly administered either NSAIDs plus PGB (30 patients) or NSAIDs alone (30 patients) for up to 4 weeks. The primary outcome was leg pain at 2 and 4 weeks. Secondary outcomes were reduction in sleep disturbances and patient global impressions of change (PGIC) at 2 and 4 weeks.

Results

Four patients in the NSAIDs plus PGB group were deemed ineligible and excluded from the study. Fewer sleep disturbances were reported by patients administered NSAIDs plus PGB compared with the NSAID monotherapy group at both 2 and 4 weeks. Additionally, the NSAIDs plus PGB group showed greater improvement in pain than the NSAID monotherapy group at 4 weeks, although this difference was not significant. PGIC was also significantly better in the NSAIDs plus PGB group than in the NSAID monotherapy group at 4 weeks. The incidence of adverse events was significantly greater in the NSAIDs plus PGB group than in the NSAID monotherapy group.

Conclusions

The combination of NSAIDs plus PGB is more effective against sleep disturbance than NSAIDs alone in patients with acute LDH, although the control of sciatic pain is minimal. Patients reported satisfactory recoveries could also be obtained, and thus, this combination therapy could be a good option for the conservative treatment of acute lumbar radicular pain, including LDH.

Benefits and safety of gabapentinoids in chronic low back pain: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND OBJECTIVE

Chronic Low Back Pain (CLBP) is very common, with a lifetime prevalence between 51% and 80%. In majority, it is nonspecific in nature and multifactorial in etiology. Pregabalin (PG) and Gabapentin (GB) are gabapentinoids that have demonstrated benefit in neuropathic pain conditions. Despite no clear rationale, they are increasingly used for nonspecific CLBP. They necessitate prolonged use and are associated with adverse effects and increased cost. Recent guidelines from the National Health Service (NHS), England, expressed concerns on their off-label use, in addition to the risk of misuse. We aimed to assess the effectiveness and safety of gabapentinoids in adult CLBP patients.

METHODS

Electronic databases of MEDLINE, EMBASE, and Cochrane were searched from their inception until December 20th, 2016. We included randomized control trials reporting the use of gabapentinoids for the treatment of CLBP of >3 months duration, in adult patients. Study selection and data extraction was performed independently by paired reviewers. Outcomes were guided by Initiative on Methods, Measurement and Pain Assessment in Clinical Trials guidelines, with pain relief and safety as the primary outcomes. Meta-analyses were performed for outcomes reported in 3 or more studies. Outcomes were reported as mean differences (MDs) or risk ratios (RRs) with their corresponding 95% confidence intervals (CIs), and I2 in percentage representing the percentage variability in effect estimates that could be explained by heterogeneity. GRADE (Grading of Recommendations Assessment, Development, and Evaluation) was used to assess the quality of evidence.

RESULTS

Out of 1,385 citations, eight studies were included. Based on the interventions and comparators, studies were analyzed in 3 different groups. GB compared with placebo (3 studies, n = 185) showed minimal improvement of pain (MD = 0.22 units, 95% CI [-0.5 to 0.07] I2 = 0%; GRADE: very low). Three studies compared PG with other types of analgesic medication (n = 332) and showed greater improvement in the other analgesic group (MD = 0.42 units, 95% CI [0.20 to 0.64] I2 = 0; GRADE: very low). Studies using PG as an adjuvant (n = 423) were not pooled due to heterogeneity, but the largest of them showed no benefit of adding PG to tapentadol. There were no deaths or hospitalizations reported. Compared with placebo, the following adverse events were more commonly reported with GB: dizziness-(RR = 1.99, 95% CI [1.17 to 3.37], I2 = 49); fatigue (RR = 1.85, 95% CI [1.12 to 3.05], I2 = 0); difficulties with mentation (RR = 3.34, 95% CI [1.54 to 7.25], I2 = 0); and visual disturbances (RR = 5.72, 95% CI [1.94 to 16.91], I2 = 0). The number needed to harm with 95% CI for dizziness, fatigue, difficulties with mentation, and visual disturbances were 7 (4 to 30), 8 (4 to 44), 6 (4 to 15), and 6 (4 to 13) respectively. The GRADE evidence quality was noted to be very low for dizziness and fatigue, low for difficulties with mentation, and moderate for visual disturbances. Functional and emotional improvements were reported by few studies and showed no significant improvements.

CONCLUSIONS AND RELEVANCE

Existing evidence on the use of gabapentinoids in CLBP is limited and demonstrates significant risk of adverse effects without any demonstrated benefit. Given the lack of efficacy, risks, and costs associated, the use of gabapentinoids for CLBP merits caution. There is need for large high-quality trials to more definitively inform this issue.

TRIAL REGISTRATION

PROSPERO CRD42016034040.

Neuropathic pain responds better to increased doses of pregabalin: an in-depth analysis of flexible-dose clinical trials

Background

Pregabalin is an effective treatment option for many patients with neuropathic pain. Higher doses of pregabalin have been shown to be more effective in improving pain outcomes but, in practice, failing to appropriately increase the dose can leave patients under-treated.

Methods

This was a pooled analysis of 6 flexible-dose clinical trials of pregabalin in patients with neuropathic pain (diabetic peripheral neuropathy, peripheral herpetic neuralgia, posttraumatic pain, or postsurgical pain). Patients were divided into “dose pathway” groups based on their weekly pregabalin dose from the start of their trial to the first week of their maintenance phase. These were: 150 mg/day only; 150 to 300 mg/day; 150 to 300 to 450 mg/day; 150 to 300 to 450 to 600 mg/day; 150 to 300 to 600 mg/day; 300 to 600 mg/day. Pain outcomes assessed for each group at each new dose were proportion of 30% and 50% responders (≥30% or ≥50% reduction in mean pain score from baseline) and mean change in pain score. Percent change in mean pain score from baseline was assessed using a marginal structural model.

Results

Seven hundred and sixty-one patients treated with flexible-dose pregabalin were included in the analysis. For each dose pathway group, there was a notably greater proportion of 30% and 50% responders and change in pain score, at each escalating dose. As assessed by the marginal structural model, higher doses of pregabalin were estimated to result in a significantly greater change in mean pain score at each week. This dose response with flexible-dose pregabalin was consistent with that previously observed with fixed-dose pregabalin.

Conclusion

Many patients who do not respond to lower doses of pregabalin will respond with notable improvements in pain outcomes when the dose is escalated. These data should encourage physicians treating patients with neuropathic pain to escalate pregabalin to the dose that delivers optimal analgesia and tolerable side effects.

Pregabalin for Neuropathic Pain: Why Benefits Could Be Expected for Multiple Pain Conditions

BACKGROUND AND OBJECTIVE

Limited research exists to support the extrapolation of the analgesic efficacy of pregabalin from one neuropathic pain condition to another. This retrospective analysis evaluated similarities in the efficacy of pregabalin for treating neuropathic pain associated with post-herpetic neuralgia (PHN), diabetic peripheral neuropathy (DPN), and spinal cord injury (SCI) in a Japanese population, as a basis for considering the extrapolation of these data to other neuropathic pain conditions.

METHODS

Data were analysed across pregabalin doses within each pain condition, from three comparable 13- to 16-week, randomized, double-blind, placebo-controlled trials (RCTs) and the corresponding 52-week, open-label extension trials of pregabalin in Japanese patients with PHN, DPN or SCI. Efficacy outcomes in the RCTs included endpoint and weekly mean pain and sleep interference scores; endpoint proportions of responders in pain; Patient Global Impression of Change scores; and 36-Item Short Form Health Survey (SF-36) scores or Hospital Anxiety and Depression Scale (HADS) assessments. Study discontinuation rates were compared between treatment groups. The extension trials assessed pain intensity, using the Short-Form McGill Pain Questionnaire.

RESULTS

In the RCTs for all pain conditions, significant improvements in comparison with placebo in mean pain and sleep interference scores were evident after 1 week with pregabalin and were sustained throughout the treatment periods (p < 0.05). At the study endpoint, in comparison with placebo, a significantly greater percentage of pregabalin-treated patients experienced a ≥30 % reduction in pain across the RCTs (p < 0.05), and pregabalin significantly improved six of 16 SF-36 subscale scores in the PHN and DPN trials (p < 0.05). In the SCI trial, pregabalin-treated patients had numerically better outcomes of HADS scores. In the extension trials, improvements in pain intensity were maintained over a 52-week period.

CONCLUSION

Similarities in the pregabalin efficacy profiles, including time to onset and magnitude of response, were confirmed regardless of the neuropathic pain condition. These data support the potential for extrapolating analgesic efficacy to other neuropathic pain conditions. CLINICALTRIALS.

GOV IDENTIFIERS

NCT00394901, NCT00553475, NCT00407745, NCT00424372, NCT00553280, NCT01202227.

Fixed-site high-frequency transcutaneous electrical nerve stimulation for treatment of chronic low back and lower extremity pain

Objective

The objective of this study was to determine if fixed-site high-frequency transcutaneous electrical nerve stimulation (FS-TENS) is effective in treating chronic low back and lower extremity pain.

Background

Transcutaneous electrical nerve stimulation is widely used for treatment of chronic pain. General-purpose transcutaneous electrical nerve stimulation devices are designed for stimulation anywhere on the body and often cannot be used while the user is active or sleeping. FS-TENS devices are designed for placement at a pre-determined location, which enables development of a wearable device for use over extended time periods.

Methods

Study participants with chronic low back and/or lower extremity pain self-administered an FS-TENS device for 60 days. Baseline, 30-, and 60-day follow-up data were obtained through an online questionnaire. The primary outcome measure was the patient global impression of change. Pain intensity and interference were assessed using the Brief Pain Inventory. Changes in use of concomitant pain medications were evaluated with a single-item global self-rating.

Results

One hundred and thirty participants were enrolled, with 88 completing the 60-day follow-up questionnaire. Most participants (73.9%) were 50 years of age or older. At baseline, low back pain was identified by 85.3%, lower extremity pain by 71.6%, and upper extremity pain by 62.5%. Participants reported widespread pain, at baseline, with a mean of 3.4 (standard deviation 1.1) pain sites. At the 60-day follow-up, 80.7% of participants reported that their chronic pain had improved and they were classified as responders. Baseline characteristics did not differentiate non-responders from responders. There were numerical trends toward reduced pain interference with walking ability and sleep, and greater pain relief in responders. There was a large difference in use of concomitant pain medications, with 80.3% of responders reporting a reduction compared to 11.8% of non-responders.

Conclusion

FS-TENS is a safe and effective option for treating chronic low back and lower extremity pain. These results motivate the use of FS-TENS in development of wearable analgesic devices.

Cost-effectiveness analysis of pregabalin for treatment of chronic low back pain in patients with accompanying lower limb pain (neuropathic component) in Japan

OBJECTIVE

To assess the cost-effectiveness of pregabalin for the treatment of chronic low back pain with accompanying neuropathic pain (CLBP-NeP) from the health care payer and societal perspectives.

METHODS

The cost-effectiveness of pregabalin versus usual care for treatment of CLBP-NeP was evaluated over a 12-month time horizon using the incremental cost-effectiveness ratio (ICER). Quality-adjusted life years (QALYs), derived from the five-dimension, five-level EuroQol (EQ-5D-5L) questionnaire, was the measure of effectiveness. Medical costs and productivity losses were both calculated. Expected costs and outcomes were estimated via cohort simulation using a state-transition model, which mimics pain state transitions among mild, moderate, and severe pain. Distributions of pain severity were obtained from an 8-week noninterventional study. Health care resource consumption for estimation of direct medical costs for pain severity levels was derived from a physician survey. The ICER per additional QALY gained was calculated and sensitivity analyses were performed to evaluate the robustness of the assumptions across a range of values.

RESULTS

Direct medical costs and hospitalization costs were both lower in the pregabalin arm compared with usual care. The estimated ICERs in the base case scenarios were approximately ¥2,025,000 and ¥1,435,000 per QALY gained with pregabalin from the payer and societal perspectives, respectively; the latter included indirect costs related to lost productivity. Sensitivity analyses using alternate values for postsurgical pain scores (0 and 5), initial pain severity levels (either all moderate or all severe), and the actual EQ-5D-5L scores from the noninterventional study showed robustness of results, with ICERs that were similar to the base case. Development of a cost-effectiveness acceptability curve showed high probability (≥75%) of pregabalin being cost-effective.

CONCLUSION

Using data and assumptions from routine clinical practice, pregabalin is cost-effective for the treatment of CLBP-NeP in Japan.