Evaluation of high protein intake to improve clinical outcome and nutritional status for patients with burns: a systematic review

•Current guidelines for patients with severe burns advise high protein intake.•These guidelines are largely based on minimal, low quality experimental evidence.•Literature review found only 4 randomised trials and none were blinded.•Only one study reported increased survival and improvements in infection rates.•Large randomised studies assessing protein intakes are recommended. Patients with severe burns undergo a local and systemic response to the injury. As part of this response the patient becomes hypermetabolic. Current guidelines advise high protein intakes to counteract the catabolic response to burns, but this appears to be based on minimal experimental evidence. Hence the aim of this review was to examine the evidence for improvements in nutritional status and clinical outcome with the administration of high protein intakes for patients with burns. Eight databases were searched for clinical trials with burn patients receiving two or more levels of protein intake at or above the level recommended for healthy individuals (0.75g/kg/d) and presenting results for at least one of the following pre-defined outcomes: nitrogen balance, length of stay, weight change, survival, physical therapy index, protein fractional synthetic rate, immunological measurements, bacteraemic days, systemic antibiotic days and net protein synthesis. Six studies were included, 4 of which were randomized trials. All had major methodological limitations, in particular none was blinded. There was too much heterogeneity in study design, patient characteristics and the timing and magnitude of the interventions to justify formal meta-analysis. There was no reliable evidence of improvement in nitrogen balance, but there was some evidence of increased weight gain on higher protein diets. One small study reported an increase in survival and significant improvements in infection rates and some indicators of immune function in children. Length of stay was not significantly improved. There was weak evidence of an improvement in muscle strength and endurance but no significant increase in protein synthesis in muscle or skin, or net protein synthesis in the whole body. There is currently only very weak evidence to justify administering high protein diets to patients following burns.