Müller 1982a.

Methods	Randomised cclinical trial, Germany
Participants	160 hospitalised adults with carcinoma of the oesophagus, stomach, colon, rectum or pancreas, at nutritional risk due to major surgery of gastrointestinal carcinoma Male:Female = 77:48 (gender not reported for 35 participants) Mean age = 59 years Exclusion criteria: Total obstructions of the gut
Interventions	Experimental group: Preoperativ parenteral nutrition. The experimental group received 10 days of preoperative parenteral nutrition group (1.5 g amino acids/kg body weight; 11 g glucose/kg body weight; electrolytes, trace elements, and vitamins) by a central venous catheter(n = 80) Control group: Treatment as usual They received regular hospital diet of 2400 kcal/day. (n = 40)
Outcomes	Postoperative complications, mortality, serum protein levels (total protein, albumin, pre‐albumin, thyroxine‐binding globin, retinol‐binding protein, transferrin), immunological status (IgA, IgM, IgG, C3A, C4, skin tests).
Study dates	Not stated
Notes	We found no contact information for the authors.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding was not possible due to the nature of the intervention.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not described
Incomplete outcome data (attrition bias) All outcomes	High risk	33 (13%) of participants were withdrawn from the trial and analysis and reasons for withdrawal were clearly stated.
Selective reporting (reporting bias)	Low risk	No protocol could be obtained, but the trial reported mortality and serious adverse events.
For‐profit bias	Unclear risk	It was unclear how the trial was funded.
Other bias	Low risk	The trial appeared to be free of other components that could put it at risk of bias.