Transcutaneous electrical nerve stimulation (TENS) for fibromyalgia in adults

Transcutaneous electrical nerve stimulation (TENS) is a newly developed method used to manage painful conditions. To date, no study has performed which includes the use of TENS for fibromyalgia. The results of this meta-analysis demonstrated that there was insufficient high-quality evidence to support the use of TENS for fibromyalgia.

To evaluate the safety and efficacy of TENS alone or combined to usual care (involving exercise) than with no treatment; exercise alone; placebo (sham) TENS;  or another treatment including electroacupuncture,  medication, hydrotherapy or warmth therapy for managing fibromyalgia among adults.

With no language barriers, MEDLINE, AMED, CINAHL, CENTRAL, PEDRO, PsycINFO, LILACS, Embase, Web of Science, and three trial registries up to 18 January 2017 to collect the associated information.  

A total of eight studies were included; one compared TENS with no treatment, two compared TENS with placebo TENS, four studies compared TENS with other therapies - superficial warmth, medication, hydrotherapy, and electroacupuncture. Two studies involved comparison of TENS with exercise or exercise alone. No research estimated participant-reported pain relief of 50% or higher or PGIC. All-inclusive, the studies were at high or unclear risk of bias, particularly, all were at great risk of bias for sample size. The primary outcome - participant-reported pain relief of 30% or higher estimated only one study. The statistical pooling was not desirable due to inadequate data and outcomes were non-homogeneous. The data regarding secondary outcomes were insufficient. No notable difference was seen within placebo and TENS for pain at rest. The authors of seven studies assumed that TENS reduced pain, but the verdicts of single small studies are questionable to be correct. One research found clinically significant improvements in the Fibromyalgia Impact Questionnaire (FIQ) subscales for anxiety, depression, fatigue, work performance, and stiffness for TENS with exercise than the exercise alone. One study determined no further improvements in FIQ scores when TENS was affixed to the first three weeks of a 12-week directed exercise programme. No major side effects were noted during the analysis. The quality of evidence recorded was very low. Due to lack of data,  GRADE rating downgraded and therefore, little reliance on the effect estimates where present.

There was inadequate high-quality evidence to support or oppose the adoption of TENS for fibromyalgia. A small number of insufficiently powered studies with deficient documentation of methodologies and treatment approaches were discovered.