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.
Competing Interests: Declaration of competing interest The author of this paper has received remunerations from Takeda and Calea in the past but no funding or other conflicts of interest in relation to this paper.
(Crown Copyright © 2023. Published by Elsevier Ltd. All rights reserved.)