Clinical relevance of trace element measurement in patients on initiation of parenteral nutrition

Abstract

Background and Aims Serum zinc, copper and selenium are measured in patients prior to commencing on parenteral nutrition; however, their interpretation can be difficult due to acute phase reactions. We assessed (i) the relationship of raised C-reactive protein with trace elements and albumin (ii) benefits of measuring trace elements when C-reactive protein is raised in patients requiring short-term parenteral nutrition. Methods Samples were collected for zinc, copper, selenium and albumin at baseline and then every two weeks and correlated with C-reactive protein results in patients on parenteral nutrition. Results were categorized into four groups based on the C-reactive protein concentrations: (i) <20 mg/L, (ii) 20-39 mg/L, (iii) 40-79 mg/L and (iv) ≥80 mg/L. Results In 166 patients, zinc, selenium and albumin correlated (Spearman's) negatively with C-reactive protein; r = -0.26, P < 0.001 (95% CI -0.40 to -0.11), r = -0.44, P < 0.001 (-0.56 to -0.29) and r = -0.22 P = 0.005 (-0.36 to -0.07), respectively. Copper did not correlate with C-reactive protein (r = 0.09, P = 0.25 [-0.07 to 0.25]). Comparison of trace elements between the four groups showed no difference in zinc and copper (both P > 0.05), whereas selenium and albumin were lower in the group with C-reactive protein > 40 mg/L ( P < 0.05). Conclusion In patients on short-term parenteral nutrition, measurement of C-reactive protein is essential when interpreting zinc and selenium but not copper results. Routine measurement of trace elements prior to commencing parenteral nutrition has to be considered on an individual basis in patients with inflammation.

ESPEN micronutrient guideline

“…Low blood levels therefore do not necessarily indicate deficiency or even depletion. Within 24 h of elective surgery in otherwise healthy individuals, plasma concentrations of many trace elements and vitamins have fallen markedly, without any change in whole body MN status [38]. The effects of inflammation in response to acute trauma or infection is usually rapid but may also be prolonged in chronic illness.…”

“…Albumin is a carrier protein for many MNs including zinc. Its level may be influenced by dilution, and by inflammation, being a negative acute phase protein [38]. Therefore, albumin determination is desirable whenever a series of MNs is determined.…”

Trace Elements in Parenteral Nutrition: Considerations for the Prescribing Clinician

“…Additionally, as ceruloplasmin is an acute phase reactant, ceruloplasmin and copper levels can be elevated in inflammatory states even in the setting of marginal copper deficiency [7]. In a recent study of 166 patients, copper levels had no correlation with C-reactive protein (CRP) levels, unlike zinc, selenium, and albumin, which were negatively correlated with CRP [10]. This highlights the difficulty in interpreting serum copper levels in the setting of inflammation.…”

“…Levels can be low in hypoalbuminemia as it is bound to albumin and alpha-macroglobulins in the blood [31]. Zinc has been found to correlate negatively with CRP [10]. A review found that, in minor illness (CRP < 15 mg/L), zinc was decreased by 10%, whereas major illness (CRP 100–200 mg/L) caused a 40%–60% decrease [32].…”

Impact of nationwide essential trace element shortages: A before‐after, single‐center analysis of hospitalized adults receiving home parenteral nutrition therapy

“…Biomarkers such as C‐reactive protein (CRP), interleukin 6, and ceruloplasmin were not consistently available for the patients in our cohort because all laboratory data measurements were traditionally entered individually by a member of the primary medical team. Therefore, we were unable to fully interpret observed micronutrient deficiencies in the context of acute inflammation 48 . Additionally, there was a shift from standard CRP assays to high‐sensitivity CRP (hs‐CRP) over the study period, thereby increasing the heterogeneity of available inflammatory markers for analysis.…”