Ishikawa 2010

Methods	Randomised trial comparing preoperative branched‐chain amino acid‐enriched supplements to usual diet in patients subsequently undergoing partial hepatectomy for the resection of benign or malignant tumours.
Participants	Patients with benign or malignant tumours.
Interventions	Intervention group received a commercial supplement (Aminoleban EN) twice daily for two weeks preoperatively and for 1 to 7 days postoperatively; the control group only consumed normal diet.
Outcomes	Mortality, duration of operation/hospitalization, intraoperative blood loss, postoperative complications including "clinical and biologic signs of hepatic dysfunction".
Category of study	Supplements/Surgical.
Sample size calculation	None reported if done.
Full paper or abstract only	Full paper.
Notes	14 patients excluded form analysis because of reasons that became apparent at the time of surgery; since the trial began 2 weeks earlier, these had to be excluded after randomisation (although that fact was not explicitly stated in the paper). Trial presented at Digestive Disease Week 2009 where additional information was available. Request for further information sent to Drs Ishikawa and Tajiri via e‐mail (martinishikawa@nms.ac.jp and tajirit@nms.ac.jp) on September 19, 2011. No response has been received as of March 20, 2012.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Patients "randomly assigned", but no further details.
Allocation concealment (selection bias)	Unclear risk	At time of presentation of paper at national meeting, stated that sealed envelopes employed, but unclear if opaque and serially numbered.
Blinding (performance bias and detection bias) All outcomes	High risk	No placebo solution employed.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Reasons for exclusion stated, but large number of dropouts (14 of original 38).
Selective reporting (reporting bias)	High risk	Explicitly stated in Methods section that lengths of stay data would be collected, but this outcome was not reported quantitatively or qualitatively.
Other bias	Unclear risk	Funder not reported.
Intent to treat analysis	High risk	14 participants unaccounted for.
Baseline imbalance?	Low risk	There were no differences in the remaining 24 patients with regard to baseline features.
Early stopping?	Unclear risk	No sample size calculation reported and there was no explanation as to why the trial was stopped when it was.