High vitamin B12 levels are not associated with increased mortality risk for ICU patients after adjusting for liver function: A cohort study

Abstract

Background and Aims Recent research has suggested that high vitamin B12 levels may be associated with increased mortality after ICU admission. However, it is known that impaired liver function may lead to elevated B12 since B12 is metabolized through the liver, and therefore high B12 levels may serve as a proxy for poor liver function. The aim of this study is to assess the impact that liver function and liver disease have on the relationship between high vitamin B12 levels and mortality in the ICU. Methods We performed an observational cohort study using ICU data that were collected from patients admitted to four ICU types (medical, surgical, cardiac care and cardiac surgery recovery) in one large urban hospital from 2001 to 2008. We analyzed the medical records of 1,684 adult patients (age ≥ 18 years) who had vitamin B12 and liver function measurements up to 14 days prior to ICU admission or within 24 hours after admission. Results While we found an association between high B12 and mortality when we did not control for any potential confounders, after we adjusted for liver function and liver disease, no significant association existed between B12 and mortality using multivariable logistic regression (30-day mortality: OR=1.18, 95% CI 0.81 to 1.72, p=0.3890; 90-day mortality: OR=1.20, 95% CI 0.84 to 1.71, p=0.3077). Conclusions Elevated B12 levels are not a significant predictor of mortality after ICU admission when liver function is controlled for, and may instead be a proxy for poor liver function.

Association of Plasma Concentration of Vitamin B12With All-Cause Mortality in the General Population in the Netherlands

“…Baseline characteristics, such as older age, high blood pressure, reduced eGFR, and elevated UAE rate, as well as increased concentrations of liver enzymes, were positively associated with higher plasma concentrations of vitamin B 12 , in agreement with findings from other studies. 3,8,11 While the cross-sectional associations as found in this study do not provide an insight for a particular cause of death, we observed that high circulating vitamin B 12 plasma concentrations were associated with significantly higher risk of all-cause mortality. The association remained significant after adjustment for established risk factors, including age, sex, BMI, type 2 diabetes, tobacco use, and alcohol consumption, as well as biomarkers associated with renal and liver function.…”

“…27 Moreover, we adjusted our results for several confounding variables, including liver function parameters, and found that the association remained, whereas other authors have reported loss of significance after such adjustment. 11 Another strength of this study is the implementation of a robust method of plasma concentration of vitamin B 12 quantification. The accuracy of the assay that we used has been evaluated using the vitamin B 12 World Health Organization International Standard.…”

“…1 While the deleterious effects of vitamin B 12 deficiency, such as anemia, neuropsychiatric symptoms, and other clinical manifestations, are well established, 2 the potential association of high plasma concentrations of vitamin B 12 with adverse health outcomes has not been fully explored. 3 Indeed, a potential association of high vitamin B 12 plasma concentrations with excess mortality has been assessed in elderly [3][4][5][6][7][8][9] and hospitalized 10,11 populations, but it has not been explored in the general population, to our knowledge.…”

The effect of the acute phase response on routine laboratory markers of folate and vitamin B12 status

“…8 MMA is a functional biomarker for B12 deficiency as it increases in deficiency because cobalamin is required for the cofactors involved in its metabolism. 5 The decrease in serum folate following surgical insult is similar to a previous report 6 but differs from another reporting no change. The hypercobalaminaemia seen in malignancies and inflammatory diseases is therefore not due to acute inflammation as previously speculated 4 and may be related to liver dysfunction rather than inflammation.…”

“…The hypercobalaminaemia seen in malignancies and inflammatory diseases is therefore not due to acute inflammation as previously speculated 4 and may be related to liver dysfunction rather than inflammation. 5 The decrease in serum folate following surgical insult is similar to a previous report 6 but differs from another reporting no change. 3 The mechanisms for this are unclear.…”