Houghton 2010.

Methods	Design: 3‐month, single blind, parallel‐group, randomised controlled study
Participants	Health condition: people with spinal cord injury Sample size: Randomisation: at participant level (one ulcer per participant)§ Randomised (participants, n; ulcers, n): 34, 34 Experimental: 16; 16 Control: 18; 18 Analysed (participants, n; ulcers, n): 34, 34 Experimental: 16; 16 Control: 18; 18 Setting, country: community‐based home care setting (1 site), Canada Inclusion criteria: participants with traumatic or non‐traumatic spinal cord injury more than 18 years of age living in the community stage II to IV pressure ulcers of at least 3 months duration pressure ulcers between 1 cm2 and 20 cm2 Exclusion criteria: participants with serious medical conditions, cardiac pacemaker, osteomyelitis, pregnancy or cancer Characteristics of pressure ulcer: Experimental Ulcer duration, mean (SD): 1.2 years (1.0) Ulcer location (n): ischial tuberosity (8), sacrum/coccyx/hip (4), leg/foot/ankle/knee (4) Ulcer stage (n): stage II (1), stage III (6), stage IV (7), unstageable (2) Control Ulcer duration, mean (SD): 3.0 years (5.6) Ulcer location (n): ischial tuberosity (11), sacrum/coccyx/ hip (8), leg/foot/ankle/knee (3) Ulcer stage (n): stage II (4), stage III (4), stage IV (10) Mean age (SD): Overall: 51 years (14) Experimental: 50 years (17) Control: 51 years (12) Gender: Experimental: 67% male Control: 50% male §It is not clearly stated whether participants or pressure ulcers were randomised but the number of pressure ulcers equals the number of participants.
Interventions	Total groups in this study: two Experimental: HVPC plus standard wound care programme (EST + SWC) Duration: 40 minutes per session; 8 sessions per day; 7 days a week; total 3 months Electrode placement: one over the ulcer and the other over intact skin at least 20 cm away from the ulcer Device, manufacturer: Micro ZC, Prizm Medical, Inc. USA Intensity of ES: intensity of the machine was set between 50 V and 150 V, gradually increased just below the onset of a muscle contraction Frequency: 10 Hz and 100 Hz Type of current: pulsed Polarity: active electrode over the ulcer and then altered each week Control: standard wound care programme Standard wound care programme for both groups Included attention to nutritional, pressure, continence and wound care needs
Outcomes	Outcomes included in this review: presented as [name of outcome in review]‐ [name of outcome in study] Proportion of pressure ulcers healed ‐ ulcer healed (expressed as numbers) Complications/adverse events ‐ adverse event (expressed in descriptive format) Rate of pressure ulcer healing ‐ percentage decrease in wound surface area (expressed as percentage per 3 months) Not useable data: presented as [name of outcome in review]‐ [name of outcome in study] Surface area of pressure ulcers ‐ wound surface area (expressed as cm2)* Composite measures of pressure ulcers ‐ photographic wound assessment tool (expressed as a number)* Other outcomes not included in this review: Pressure Sore Status Tool ES therapy compliance Time point included in this review: month 3 (end of intervention) Other time points: baseline *SD not provided
Notes	Withdrawals, (n; reason): Experimental: none Control: none Funding source: the study was supported by: Ontario Neurotrauma Foundation (grant no. 2004‐SCI‐SC‐01), which required matching with in‐kind support from industrial partners Prizm Medical Inc., The Roho Group, Argentum Medical Inc., and Dermasciences Canada Inc. for equipment and supplies Trial registration or published protocol: no information about trial registration or published protocol provided
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "…random number generation…" p670
Allocation concealment (selection bias)	Low risk	Quote: "Eligible subjects were then assigned to receive either SWC or EST SWC using a concealed, random process that involved opening an opaque envelope prepared by an independent person with random number generation." p670
Blinding of participants (performance bias) All outcomes	High risk	Quote: "This single‐blind study was not set up in a manner that blinded subjects receiving EST." p676 Comment: not possible to blind participants
Blinding of personnel (performance bias) All outcomes	High risk	Comment: not possible to blind personnel
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "Both the acetate tracings and digital images were analyzed by a single assessor who was not involved in either EST or standard wound treatment and was blind to group assignment."p672 Quote: "In this way, results from several centers can be sent to a single assessor who is blind to treatment allocation." p675 Comment: assessor was blinded to all outcomes
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "All of the subjects enrolled in the study completed the 3‐month study period" p675 Comment: no dropouts
Selective reporting (reporting bias)	High risk	Comment: the total number of wounds healed is not reported. Insufficient data on PWAT and no data on PSST
Other bias	High risk	Comment: At 3 months, control participants could move to experimental group Trial was sponsored by third parties who were likely to have a vested interest in a positive finding