Transcutaneous electrical nerve stimulation (TENS) for fibromyalgia in adults

Abstract

Background: Fibromyalgia is characterised by persistent, widespread pain; sleep problems; and fatigue. Transcutaneous electrical nerve stimulation (TENS) is the delivery of pulsed electrical currents across the intact surface of the skin to stimulate peripheral nerves and is used extensively to manage painful conditions. TENS is inexpensive, safe, and can be self-administered. TENS reduces pain during movement in some people so it may be a useful adjunct to assist participation in exercise and activities of daily living. To date, there has been only one systematic review in 2012 which included TENS, amongst other treatments, for fibromyalgia, and the authors concluded that TENS was not effective.

Objectives: To assess the analgesic efficacy and adverse events of TENS alone or added to usual care (including exercise) compared with placebo (sham) TENS; no treatment; exercise alone; or other treatment including medication, electroacupuncture, warmth therapy, or hydrotherapy for fibromyalgia in adults.

Search methods: We searched the following electronic databases up to 18 January 2017: CENTRAL (CRSO); MEDLINE (Ovid); Embase (Ovid); CINAHL (EBSCO); PsycINFO (Ovid); LILACS; PEDRO; Web of Science (ISI); AMED (Ovid); and SPORTDiscus (EBSCO). We also searched three trial registries. There were no language restrictions.

Selection criteria: We included randomised controlled trials (RCTs) or quasi-randomised trials of TENS treatment for pain associated with fibromyalgia in adults. We included cross-over and parallel-group trial designs. We included studies that evaluated TENS administered using non-invasive techniques at intensities that produced perceptible TENS sensations during stimulation at either the site of pain or over nerve bundles proximal (or near) to the site of pain. We included TENS administered as a sole treatment or TENS in combination with other treatments, and TENS given as a single treatment or as a course of treatments.

Data collection and analysis: Two review authors independently determined study eligibility by assessing each record and reaching agreement by discussion. A third review author acted as arbiter. We did not anonymise the records of studies before assessment. Two review authors independently extracted data and assessed risk of bias of included studies before entering information into a 'Characteristics of included studies' table. Primary outcomes were participant-reported pain relief from baseline of 30% or greater or 50% or greater, and Patient Global Impression of Change (PGIC). We assessed the evidence using GRADE and added 'Summary of findings' tables.

Main results: We included eight studies (seven RCTs, one quasi-RCT, 315 adults (299 women), aged 18 to 75 years): six used a parallel-group design and two used a cross-over design. Sample sizes of intervention arms were five to 43 participants.Two studies, one of which was a cross-over design, compared TENS with placebo TENS (82 participants), one study compared TENS with no treatment (43 participants), and four studies compared TENS with other treatments (medication (two studies, 74 participants), electroacupuncture (one study, 44 participants), superficial warmth (one cross-over study, 32 participants), and hydrotherapy (one study, 10 participants)). Two studies compared TENS plus exercise with exercise alone (98 participants, 49 per treatment arm). None of the studies measured participant-reported pain relief of 50% or greater or PGIC. Overall, the studies were at unclear or high risk of bias, and in particular all were at high risk of bias for sample size.Only one study (14 participants) measured the primary outcome participant-reported pain relief of 30% or greater. Thirty percent achieved 30% or greater reduction in pain with TENS and exercise compared with 13% with exercise alone. One study found 10/28 participants reported pain relief of 25% or greater with TENS compared with 10/24 participants using superficial warmth (42 °C). We judged that statistical pooling was not possible because there were insufficient data and outcomes were not homogeneous.There were no data for the primary outcomes participant-reported pain relief from baseline of 50% or greater and PGIC.There was a paucity of data for secondary outcomes. One pilot cross-over study of 43 participants found that the mean (95% confidence intervals (CI)) decrease in pain intensity on movement (100-mm visual analogue scale (VAS)) during one 30-minute treatment was 11.1 mm (95% CI 5.9 to 16.3) for TENS and 2.3 mm (95% CI 2.4 to 7.7) for placebo TENS. There were no significant differences between TENS and placebo for pain at rest. One parallel group study of 39 participants found that mean ± standard deviation (SD) pain intensity (100-mm VAS) decreased from 85 ± 20 mm at baseline to 43 ± 20 mm after one week of dual-site TENS; decreased from 85 ± 10 mm at baseline to 60 ± 10 mm after single-site TENS; and decreased from 82 ± 20 mm at baseline to 80 ± 20 mm after one week of placebo TENS. The authors of seven studies concluded that TENS relieved pain but the findings of single small studies are unlikely to be correct.One study found clinically important improvements in Fibromyalgia Impact Questionnaire (FIQ) subscales for work performance, fatigue, stiffness, anxiety, and depression for TENS with exercise compared with exercise alone. One study found no additional improvements in FIQ scores when TENS was added to the first three weeks of a 12-week supervised exercise programme.No serious adverse events were reported in any of the studies although there were reports of TENS causing minor discomfort in a total of 3 participants.The quality of evidence was very low. We downgraded the GRADE rating mostly due to a lack of data; therefore, we have little confidence in the effect estimates where available.

Authors' conclusions: There was insufficient high-quality evidence to support or refute the use of TENS for fibromyalgia. We found a small number of inadequately powered studies with incomplete reporting of methodologies and treatment interventions.

Conflict of interest statement

MIJ: none known. MIJ is a physiologist and authored a book "TENS. Research to Clinical Practice" in 2014. He is also involved in the professional training of healthcare practitioners about the use of TENS.

LSC: none known. LSC is a qualified physiotherapist and is involved in the professional training of physiotherapists about the use of TENS.

GPH: none known.

GJ: none known.

CAP: none known. CAP is a qualified physiotherapist and is involved in the professional training of physiotherapists about the use of TENS.

Figures

1

Study flow diagram.

2

Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.

3

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

References

References to studies included in this review Carbonario 2013 {published data only}

Dailey 2013 {published data only} da Silva 2008 {published data only} Di Benedetto 1993 {published data only} Guo 2005 {published data only} Lauretti 2013 {published data only} Lofgren 2009 {published data only} Mutlu 2013 {published data only} References to studies excluded from this review Arroyo 1993 {published data only} Ido 2003 {published data only} Kesiktas 2011 {published data only} Mutlu 2006 {published data only} Simons 2006 {published data only} Sunshine 1996 {published data only} References to ongoing studies Noehren 2015 {unpublished data only} Additional references Aarskog 2007 AlBalawi 2013 APTA 2001 Bates 1980 Bennett 2007 Bennett 2011 Bidonde 2014 Bidonde 2017 Bjordal 2003 Bjordal 2007 Boutron 2008 Busch 2008 Busse 2015 Catley 2015 Charlton 2005 Chen 2008 Chen 2011 Chesterton 2003 Claydon 2008a Claydon 2008b Claydon 2010 Claydon 2013 Dechartres 2013 DeSantana 2009 Deyo 1990 Dowswell 2009 Dworkin 2008 Francis 2011 Furlan 2009 Garrison 1996 Gibson 2017 Gladwell 2015a Gladwell 2015b Goldenberg 1987 GRADEpro GDT 2015 [Computer program] Guyatt 2008 Guyatt 2013a Guyatt 2013b Higgins 2011 Houghton 2010 Hurlow 2012 Häuser 2012 Johnson 1992 Johnson 2007 Johnson 2010 Johnson 2011 Johnson 2014 Johnson 2015a Johnson 2015b Kalra 2001 Khadilkar 2008 King 2001 Koroschetz 2011 L'Abbé 1987 Leonard 2010 Leonard 2011 Liberati 2009 Lunn 2014 Ma 2001 Macfarlane 2017 Maeda 2007 Melzack 1965 Millan 2002 Moore 1998 Moore 2008 Moore 2009 Moore 2010a Moore 2010b Moore 2010c Moore 2010d Moore 2011a Moore 2011b Moore 2011c Moore 2012a Moore 2012b Moore 2013a Moore 2013b Moore 2013c Moore 2014a Moore 2014b Moran 2011 Nardone 1989 Nüesch 2010 O'Brien 2010 Pallett 2014 PaPaS 2012 Porfírio 2015 Queiroz 2013 Rakel 2010 RevMan 2014 [Computer program] Rutjes 2009 Santos 2013 Sluka 1998 Sluka 1999 Sluka 2000 Sluka 2006 Sluka 2013 Somers 2009 Straube 2008 Straube 2010 Straube 2011 Sultan 2008 Vance 2007 Vos 2012 Wiffen 2013 Winkelmann 2012 Winkelmann 2017 Winklemann 2011 Wolfe 1990 Wolfe 2010 Wolfe 2013 Wolfe 2014 References to other published versions of this review Nnoaham 2008