Taylor 2013

Methods	Parallel RCT
Participants	Country of study: USA Setting: community rheumatology practices Condition: fibromyalgia Prior management details: not reported but continued stable medication usage n = 57 (46 after dropout) Age mean (SD): active group 51 (10.6) years, sham group 51.5 (10.9) years, usual care group 48.6 (9.8) years Duration of symptoms: not reported Gender distribution: 43 F, 3 M (data reported on completers)
Interventions	Stimulation type: CES Stimulation parameters: frequency 0.5 Hz; pulse width not specified; intensity 100 μA; waveform shape square wave biphasic, duration 1 h per session Stimulation location: earlobe clip electrodes Number of treatments: x 1 daily for 8 weeks Control type: sham CES unit indistinguishable from active unit
Outcomes	Primary: pain VAS, anchors not reported When taken: at the end of each week of treatment period Secondary: FIQ
Notes	COI: no declaration made Sources of support: University of Virginia. Center for the study of Complementary and Alternative Therapies. Devices loaned by Electromedical Products International
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: described as randomised but method of randomisation not reported
Allocation concealment (selection bias)	Unclear risk	Comment: allocation concealment not reported
Adequate blinding of participants?	Low risk	Comment: identical devices given to sham and active group with subsensory stimulation parameters
Adequate blinding of assessors?	Low risk	Comment: participants self‐rated at home
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: of 57, 11 did not complete ‐  unclear if ITT analysis employed. However, only 2‐4 per group and balanced, mostly due to assessment burden
Selective reporting (reporting bias)	Low risk	Comment: while no numeric data were provided on primary outcomes in the study report, these data were provided upon request to the authors
Study Size	High risk	Comment: < 50 participants per treatment arm
Study duration	High risk	Comment: < 2 weeks' follow‐up
Other bias	Low risk	Comment: no other source of bias detected