Diaz‐Valenzuela 2014.

Methods	Trial design: RCT Trial grouping: parallel Ethics and informed consent: yes Follow‐up period: 30 days Sample size estimate: yes (560 people required) ITT analysis: no; number randomised: 247; number analysed: 229 Funding: Ministry of Health of the Government of Andalusia, in the call for Research Biomedical and Health Sciences in Andalusia 2010 with No. of record PI‐ 0772‐2010
Participants	Country: Spain Setting: nursing homes in the province of Córdoba Number: 247 people recruited (121 olive oil group; 112 included in analysis; 126 fatty acid group, 117 in analysis) Inclusion criteria: people living in nursing homes with moderate or high risk of PUs (≥ 14 on the Braden scale) Exclusion criteria: people with an existing PU; those with vascular disease or those with an extremely poor medical condition Pretreatment: mean age: olive oil: 84,06 years; fatty acid: 81.7 years mean Braden score: olive oil: 12.06; fatty acid: 12.09 men: olive oil: 19%; fatty acid: 27.8% incontinent urine: olive oil: 6.6%; fatty acid: 11.9% incontinent mixed: olive oil: 83.4%; fatty acid: 88.1% repositioning: olive oil: 33,1%; fatty acid: 27.8% pressure redistribution mattresses: olive oil: 43.0%; fatty acid: 32.5% local pressure redistribution devices: olive oil: 38.8%; fatty acid: 39.7% nutritional supplements: olive oil: 8.3%; fatty acid: 3.28% Both groups were equivalent at baseline
Interventions	Intervention group: application every 12 h to risk areas, of extra virgin olive oil (Oleicopiel) Control group: application every 12 h to risk areas, of HOFAs (Mepentol)
Outcomes	Primary outcomes: PU incidence Outcome type: dichotomous outcome Reporting: fully reported Unit of measure: numbers Direction: lower is better Data value: endpoint Secondary outcomes: Time to onset of the PU Outcome type: continuous outcome Reporting: fully reported Unit of measure: survival analysis Direction: higher is better Data value: endpoint
Identification	Author's name: Antonio Díaz Valenzuela Institution: Hospital de Alta Resolución de Puente Genil Email: adiaz@ephag.es Address: Miguel Quintero Merino, 14500 Puente Genil (Córdoba)
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer software (Epidat 3.1) was used to generate random number sequence (ratio 1:1)
Allocation concealment (selection bias)	Unclear risk	Not mentioned
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Double‐blind
Incomplete outcome data (attrition bias) All outcomes	Low risk	Similar numbers and with similar reasons from each group were lost to follow‐up
Selective reporting (reporting bias)	Low risk	Although the protocol was not viewed, PU development and time to PU development were assessed. These are expected outcomes in this type of study.
Other bias	Low risk	Baseline characteristics were similar and there were no other risks of bias obvious