The Effects of Different Parenteral Nutrition Lipid Formulations on Clinical and Laboratory Endpoints in Patients Receiving Home Parenteral Nutrition: A Systematic Review

Summary Background Home parenteral nutrition (HPN) is a life-sustaining therapy for individuals with intestinal failure in a community setting. It refers to the intravenous infusion of macronutrients, micronutrients, fluids and electrolytes. Routinely used HPN solutions contain different quantities of these components. Consequently, each HPN solution may have different impacts on metabolism, inflammation and oxidative stress. Long-term use of HPN can lead to a number of adverse health outcomes including the development of metabolic bone disease, intestinal failure associated liver disease and poor quality of life but whether, and how, the composition of HPN solutions contributes to these health sequelae is poorly understood. The aim of this study is to systematically review and evaluate the evidence for the differential effects of HPN solutions and to understand what features are associated with differences in clinical endpoints. Methods A systematic literature search was conducted between September and December 2020, and updated in July 2021 using the MEDLINE (Ovid), EMBASE, Scopus, and Web of Science databases. Studies were selected according to the following criteria (a) adult participants (>18 years old) dependent on HPN; (b) randomised controlled trials, prospective cohort and cross-sectional study designs; (c) primary research comparing two or more HPN solutions and (d) published in English language. Data were extracted and study quality assessed using Cochrane Collaboration’s tools: Risk of Bias for Randomised Controlled Trials (RCTs); Risk of Bias in Non-Randomised Studies of Interventions; and the Newcastle Ottawa Scale for cross-sectional studies. Results Of the 5148 articles identified, seven RCTs, two prospective cohort and one cross-sectional study were included with a total of 295 participants. Studies varied in terms of duration (one to 60 months) and sample size (n=5 to 88). Ten studies compared lipid emulsions (LE) and one study also compared LE with lipid-free HPN. No studies were found that compared the amino acid, vitamin, trace element or electrolyte components of HPN. In general, LE were well tolerated with no significant adverse effects. LE containing olive +/or fish oil were associated with a lower ω-6:ω-3 fatty acid ratio, positive reductions in markers of liver function, and changes in blood and cell fatty acid profiles. Conclusions Despite the increasing use of HPN, there is surprisingly little evidence available to guide the provision of macro and micronutrients in the adult population requiring this therapy. Although LE containing olive +/or fish oil show promise with regards to liver function and blood and cell fatty acid profiles, further studies are needed before drawing definitive conclusions on the clinical value of these emulsions. It is likely that one type of HPN solution alone cannot be uniformly applied to patient care, and each patient should be assessed on an individual basis.