Palese 2013

Methods	Design: randomised and self‐controlled trial
Participants	Baseline: 150 participants ‐ 102 female and 48 male; mean age of participants was 74.8 (SD 12.37) years Setting: patients who were hospitalised in the 2 orthopaedic units of a teaching hospital in northern Italy Country: Italy Injection site: left or right side of lower abdomen Injection protocol: needle gauge 27.5, 5/8 inch, syringe volume 0.4 mL, enoxaparin 4000 IU Inclusion criteria: received SC injection of LMWH, were monitored for at least 3 days after first injection Exclusion criteria: already received SC heparin injection; had haematological, cardiologic, or liver disease; were pregnant; were taking oral anticoagulant or antiaggregate drugs; had altered integrity of abdominal skin
Interventions	Slow injection (30 seconds) vs fast injection of heparin (10 seconds) Time between 2 injections was 24 hr.
Outcomes	Extent of injection site bruising was evaluated at 48 hr after each injection with a plastic ruler to measure maximum horizontal diameter of bruise recorded as mm
Notes	Funding sources: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation was reported but how sequence was generated was not described. Quote: "the order of the treatment (A or B) was randomly selected." The CIS contacted trial authors to ask for information about randomisation method; trial authors stated that random sequence was generated by computer.
Allocation concealment (selection bias)	Unclear risk	Method not stated
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and personnel blinding was impossible in this trial.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "The decision (treatment A, 10 seconds left hypochondrium; treatment B, 30 seconds right hypochondrium) was written in a paper and placed in an envelope and kept in a locked safe." Quote: "Nurses evaluating the bruising did not know which treatment had been performed on the left and right side of the abdomen. The data analysis was also performed in a blinded fashion. The envelope containing this information was opened after analysis was complete."
Incomplete outcome data (attrition bias) All outcomes	Low risk	Trial authors reported no losses to follow‐up.
Selective reporting (reporting bias)	Low risk	All stated outcomes were reported.
Other bias	Low risk	No potential other bias was identified.