Acupuncture for neuropathic pain in adults (Review)

chenyaoxin

ABSTRACT
Background
Neuropathicpain may be caused by nerve damage, and is often followed by changes to thecentral nervous system. Uncertainty remains regarding the effectiveness andsafety of acupuncture treatments for neuropathic pain, despite a number ofclinical trials being undertaken.
Objectives
Toassess the analgesic efficacy and adverse events of acupuncture treatments forchronic neuropathic pain in adults.
Searchmethods
Wesearched CENTRAL, MEDLINE, Embase, four Chinese databases, ClinicalTrials.govand World Health Organization (WHO) International Clinical Trials RegistryPlatform (ICTRP) on 14 February 2017. We also cross checked the reference listsof included studies.
Selectioncriteria
Randomisedcontrolled trials (RCTs) with treatment duration of eight weeks or longercomparing acupuncture (either given alone or in combination with othertherapies) with sham acupuncture, other active therapies, or treatment as usual,for neuropathic pain in adults. We searched for studies of acupuncture based onneedle insertion and stimulation of somatic tissues for therapeutic purposes,and we excluded other methods of stimulating acupuncture points without needleinsertion. We searched for studies of manual acupuncture, electroacupuncture orother acupuncture techniques used in clinical practice (such as warm needling,fire needling, etc).
Datacollection and analysis
Weused the standard methodological procedures expected by Cochrane. The primaryoutcomes were pain intensity and pain relief. The secondary outcomes were anypain-related outcome indicating some improvement, withdrawals, participantsexperiencing any adverse event, serious adverse events and quality of life. Fordichotomous outcomes, we calculated risk ratio (RR) with 95% confidenceintervals (CI), and for continuous outcomes we calculated the mean difference(MD) with 95% CI. We also calculated number needed to treat for an additionalbeneficial outcome (NNTB) where possible. We combined all data using arandom-effects model and assessed the quality of evidence using GRADE togenerate ’Summary of findings’ tables.
Mainresults
Weincluded six studies involving 462 participants with chronic peripheralneuropathic pain (442 completers (251 male), mean ages 52 to 63 years). Theincluded studies recruited 403 participants from China and 59 from the UK. Moststudies included a small sample size (fewer than 50 participants per treatmentarm) and all studies were at high risk of bias for blinding of participants andpersonnel. Most studies had unclear risk of bias for sequence generation (fourout of six studies), allocation concealment (five out of six) and selectivereporting (all included studies). All studies investigated manual acupuncture,and we did not identify any study comparing acupuncture with treatment asusual, nor any study investigating other acupuncture techniques (such aselectroacupuncture, warm needling, fire needling).
Onestudy compared acupuncture with sham acupuncture. We are uncertain if there isany difference between the two interventions on reducing pain intensity (n =45; MD -0.4, 95% CI -1.83 to 1.03, very low-quality evidence), and neithergroup achieved ’no worse than mild pain’ (visual analogue scale (VAS, 0-10)average score was 5.8 and 6.2 respectively in the acupuncture and shamacupuncture groups, where 0 = no pain). There was limited data on quality oflife, which showed no clear difference between groups. Evidence was notavailable on pain relief, adverse events or other pre-defined secondaryoutcomes for this comparison.
Threestudies compared acupuncture alone versus other therapies (mecobalamin combinedwith nimodipine, and inositol). Acupuncture may reduce the risk of ’no clinicalresponse’ to pain than other therapies (n = 209; RR 0.25, 95% CI 0.12 to 0.51),however, evidence was not available for pain intensity, pain relief, adverseevents or any of the other secondary outcomes.
Twostudies compared acupuncture combined with other active therapies (mecobalamin,and Xiaoke bitong capsule) versus other active therapies used alone. We foundthat the acupuncture combination group had a lower VAS score for pain intensity(n = 104; MD -1.02, 95% CI -1.09 to -0.95) and improved quality of life (n =104; MD -2.19, 95% CI -2.39 to -1.99), than those receiving other therapyalone. However, the average VAS score of the acupuncture and control groups was3.23 and 4.25 respectively, indicating neither group achieved ’no worse thanmild pain’. Furthermore, this evidence was from a single study with high riskof bias and a very small sample size. There was no evidence on pain relief andwe identified no clear differences between groups on other parameters,including ’no clinical response’ to pain and withdrawals. There was no evidenceon adverse events.
Theoverall quality of evidence is very low due to study limitations (high risk ofperformance, detection, and attrition bias, and high risk of bias confounded bysmall study size) or imprecision. We have limited confidence in the effectestimate and the true effect is likely to be substantially different from theestimated effect.
Authors’conclusions
Dueto the limited data available, there is insufficient evidence to support orrefute the use of acupuncture for neuropathic pain in general, or for anyspecific neuropathic pain condition when compared with sham acupuncture orother active therapies. Five studies are still ongoing and seven studies areawaiting classification due to the unclear treatment duration, and the resultsof these studies may influence the current findings.