Polak 2018.

Methods	Design: 8‐week prospective, parallel‐group, randomised controlled study
Participants	Health condition: people with neurological injuries Sample size: Randomisation: at participant level (more than one ulcer for some participants)§ Randomised (participants, n; ulcers, n): 61; not reported Experimental 1: 20; not reported Experimental 2: 21; not reported Control: 20; not reported Analysed (participants, n; ulcers, n): 61; not reported Experimental 1: 20; not reported Experimental 2: 21; not reported Control: 20; not reported Setting, country: rehabilitation centre (number of sites: 1), Poland Inclusion criteria: people with neurological conditions (spinal cord injury, stroke and brain injury) 18 years or more with high risk of pressure ulcer development (< 14 points on Norton scale and > 15 on the Waterlow scale) stage II, III and IV pressure ulcers of at least 0.5 cm2 (NPUAP classification) located on the pelvic girdle or lower extremities duration of pressure ulcers at least 4 weeks duration Exclusion criteria: participants with acute inflammation in the wound area participants with medical conditions impeding wound healing participants with cancer, electronic or metal implants, malignancy, tunnelling, necrotic wound likely to involve osteomyelitis and in need of surgical intervention Characteristics of pressure ulcer: Experimental 1 Ulcer duration, mean (SD): 13.9 weeks (11.2) Ulcer location (n): sacrum (15), greater trochanter or ischial tuberosity (2), lower leg or foot (3) Ulcer stage (n): stage II (2), stage III (13), stage IV (5) Experimental 2 Ulcer duration, mean (SD): 11.6 weeks (9.0) Ulcer location (n): sacrum (16), greater trochanter or ischial tuberosity (2), lower leg or foot (3) Ulcer stage (n): stage II (4), stage III (12), stage IV (5) Control Ulcer duration, mean (SD): 10.9 weeks (8.6) Ulcer location (n): sacrum (14), greater trochanter or ischial tuberosity (3), lower leg or foot (3) Ulcer stage, (n): stage II (3), stage III (13), stage IV (4) Mean age (SD): Experimental group 1: 53 years (14) Experimental group 2: 56 years (18) Control group: 53 years (13) Gender: Experimental group 1: 60% male Experimental group 2: 48% male Control group: 60% male §It is clearly stated that in participant with multiple pressure ulcer, all wounds were treated but only one pressure ulcer per participant was analysed.
Interventions	Total groups in this study: three Experimental 1: anodal ES group plus standard wound care (AG group) Duration: 50 minutes per session; 1 session per day; 5 days a week; total 8 weeks Electrode placement: one over the ulcer and the other on the healthy skin 20 cm away from ulcer Device, manufacturer: Intelect Advanced Combo unit (Model 2771 Chattanooga Group, California USA) Intensity of ES: sensory perception Frequency: 100 Hz Type of current: pulsed Polarity: anode over the ulcer for entire duration of the study Experimental 2: cathodal ES group plus standard wound care (CG group) Duration: 50 minutes per session; 1 session per day; 5 days a week; total 8 weeks Electrode placement: one over the ulcer and the other on the healthy skin 20 cm away from ulcer Device, manufacturer: Intelect Advanced Combo unit (Model 2771 Chattanooga Group, California USA) Intensity of ES: sensory perception Frequency: 100 Hz Type of current: pulsed Polarity: cathode over the ulcer for entire duration of the study Control: placebo ES group plus standard wound care (PG group) Same settings and duration as Experimental 1 but without current Control group: standard wound care Included pressure ulcer prevention measures, wound care and physical treatment
Outcomes	Outcomes included in this review: presented as [name of outcome in review]‐ [name of outcome in study] Surface area of pressure ulcer ‐ wound surface area (expressed in cm2) Proportion of pressure ulcers healed ‐ pressure ulcers closed (expressed as numbers) Complications/adverse events ‐ adverse event (expressed in descriptive format) Rate of pressure ulcer healing‐ percentage area reduction (expressed as percentage per 8 weeks)* Other outcomes not included in this review: Periwound skin blood flow† Time point included in this review: week 8 (end of intervention) converted from percentage per 8 weeks to percentage per week † measured at 2 weeks and 4 weeks only
Notes	Withdrawals, (n; reason): Experimental 1: 3; health deteriorated, 3; discharged, 1; withdrawn Experimental 2: 2; health deteriorated, 3; discharged Control: 4; health deteriorated, 2; withdrawn, 2; died Funding source: all research activities were funded by the Academy of Physical Education, Katowice, Poland Registry or published protocol: prospectively registered at Australian New Zealand Clinical Trials Registry (identifier ANZCTRN12615001281583)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: “……..inserted the slips into 45 computer‐generated, randomly drawn envelopes.” and “3 additional sets of 6 envelopes were prepared for each group and the randomization of patients proceeded as described.”p12
Allocation concealment (selection bias)	Low risk	Quote: “Before the trial commenced, the envelopes were opened 1 at a time in the presence of a physiotherapist and the patient concerned was directed to the appropriate group.” p12
Blinding of participants (performance bias) All outcomes	Low risk	Quote: “All patients……were blinded…..” p12
Blinding of personnel (performance bias) All outcomes	High risk	Quote: “The exceptions were … the principal physiotherapist who set the equipment to apply active or sham ES.” p12
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: “First, the research team (physicians, nurses, physiotherapists), the person in charge of measuring WSA, and the statistician were blinded as to treatment provided.” p27
Incomplete outcome data (attrition bias) All outcomes	High risk	Comment: 20/60 (33%) dropouts
Selective reporting (reporting bias)	Low risk	Comment: all pre stated outcomes were reported
Other bias	Low risk	Comment: appears free of other bias