An evaluation of plasma vitamin C concentrations in individuals requiring home parenteral nutrition

A scoping review of parenteral requirements (macronutrients, fluid, electrolytes and micronutrients) in adults with chronic intestinal failure receiving home parenteral nutrition

INTRODUCTION

Home parenteral nutrition (HPN) prescriptions should be individualised in adults with chronic intestinal failure (IF). The aims of the review were to explore HPN requirements and available guidelines and to determine whether adults (≥ 18 years) receive recommended parenteral nutrient doses.

METHODS

Online databases searches identified empirical evidence (excluding case-reports), reviews and guidelines (Published 2006-2024 in English language). Additional reference lists were hand-searched. Older studies, cited in national guidelines were highlighted to map evidence source. Two reviewers screened 1660 articles independently, with 98 full articles assessed and 78 articles included (of which 35 were clinical studies). Citation tracking identified 12 older studies.

RESULTS

A lack of evidence was found assessing parenteral macronutrient (amounts and ratios to meet energy needs), fluid and electrolyte requirements. For micronutrients, 20 case series reported serum levels as biomarkers of adequacy (36 individual micronutrient levels reported). Studies reported levels below (27 out of 33) and above (24 out of 26) reference ranges for single micronutrients, with associated factors explored in 11 studies. Guidelines stated recommended parenteral dosages. Twenty-four studies reported variable proportions of participants receiving HPN dosages outside of guideline recommendations. When associated factors were assessed, two studies showed nutrient variation with type of HPN administered (multichamber or individually compounded bags). Five studies considered pathophysiological IF classification, with patients with short bowel more likely to require individualised HPN and more fluid and sodium.

CONCLUSIONS

This review highlights substantial evidence gaps in our understanding of the parenteral nutritional requirements of adult receiving HPN. The conclusions drawn were limited by temporal bias, small samples sizes, and poor reporting of confounders and dose. Optimal HPN nutrient dose still need to be determined to aid clinical decision-making and further research should explore characteristics influencing HPN prescribing to refine dosing recommendations.

25 year experience of patterns of plasma vitamin C levels in patients requiring home parenteral support

OBJECTIVE

Vitamin C deficiency is common in patients with chronic intestinal failure. Risk factors are poorly understood and guidelines for monitoring largely based on expert opinion. The aim of this study was to describe patterns of vitamin C deficiency in patients on long-term home parenteral support (HPS).

DESIGN

A retrospective review of a prospectively collated database for 236 HPS patients cared for in Glasgow, from 1998 to 2023, was interrogated for subjects with paired CRP and vitamin C measurements. Following analysis of the impact of CRP on vitamin C levels, further review of associated clinical, micronutrient and dietetic details in those with a paired CRP <5 mg L-1 were used to identify risk factors for hypoascorbataemia.

RESULTS

1527 recorded episodes with paired CRP and vitamin C measurements were analysed. Period prevalence of hypoascorbataemia was between 29.3 and 52.5%, depending on choice of the lower reference range for vitamin C as either 15 μmol L-1 or 26.1 μmol L-1. The influence of CRP appeared most significant early during HPS with other factors, including extensive mucosal disease, precedent surgery or presence of a colostomy identified as more significant on multivariate analysis for those on long-term HPS (OR 1.3261-1.5609, 1.0752-1.1008, and 0.6260-0.6663 for threshold vitamin C of 26.1 or 15 μmol L-1 respectively).

CONCLUSION

Vitamin C may present differently in long term HPS patients in comparison to those in the acute phase of illness. An evidence based approach to guideline development should be promoted to reduce morbidity.