Effects of Vitamin C on Organ Function in Cardiac Surgery Patients: A Systematic Review and Meta-Analysis

Hill, Aileen; Clasen, Kai C.; Wendt, Sebastian; Majoros, Ádám G.; Stoppe, Christian; Adhikari, Neill K. J.; Heyland, Daren K.; Benstoem, Carina

doi:10.3390/nu11092103

Cited by 35 publications

(50 citation statements)

References 47 publications

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“…Our current metaanalysis was restricted to trials that tested vitamin C alone. A fourth recent meta-analysis concluded that vitamin C shortens ventilation time in cardiac surgery patients [50]; however, the study was shown to contain several substantial statistical errors [51].…”

Section: Discussionmentioning

confidence: 99%

Vitamin C may reduce the duration of mechanical ventilation in critically ill patients: a meta-regression analysis

2020

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Background: Our recent meta-analysis indicated that vitamin C may shorten the length of ICU stay and the duration of mechanical ventilation. Here we analyze modification of the vitamin C effect on ventilation time, by the control group ventilation time (which we used as a proxy for severity of disease in the patients of each trial). Methods: We searched MEDLINE, Scopus, and the Cochrane Central Register of Controlled Trials and reference lists of relevant publications. We included controlled trials in which the administration of vitamin C was the only difference between the study groups. We did not limit our search to randomized trials and did not require placebo control. We included all doses and all durations of vitamin C administration. One author extracted study characteristics and outcomes from the trial reports and entered the data in a spreadsheet. Both authors checked the data entered against the original reports. We used meta-regression to examine whether the vitamin C effect on ventilation time depends on the duration of ventilation in the control group.Results: We identified nine potentially eligible trials, eight of which were included in the meta-analysis. We pooled the results of the eight trials, including 685 patients in total, and found that vitamin C shortened the length of mechanical ventilation on average by 14% (P = 0.00001). However, there was significant heterogeneity in the effect of vitamin C between the trials. Heterogeneity was fully explained by the ventilation time in the untreated control group. Vitamin C was most beneficial for patients with the longest ventilation, corresponding to the most severely ill patients. In five trials including 471 patients requiring ventilation for over 10 h, a dosage of 1-6 g/day of vitamin C shortened ventilation time on average by 25% (P < 0.0001). Conclusions: We found strong evidence that vitamin C shortens the duration of mechanical ventilation, but the magnitude of the effect seems to depend on the duration of ventilation in the untreated control group. The level of baseline illness severity should be considered in further research. Different doses should be compared directly in future trials.

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Section: Discussionmentioning

confidence: 99%

Vitamin C may reduce the duration of mechanical ventilation in critically ill patients: a meta-regression analysis

2020

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“…We believe that this conclusion is incorrect based on the evidence presented. This particularly small p-value from Figure 6 [2] is associated with the test of heterogeneity, not with the test of overall effect (p = 0.02, Z = 2.27). In the abstract, this same error occurs for ICU length of stay and hospital length of stay in that the reported p-values are from the heterogeneity tests, not from the tests of overall effect.…”

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confidence: 86%

“…. ventilation time (p < 0.00001)" [2]. We believe that this conclusion is incorrect based on the evidence presented.…”

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confidence: 88%

“…

We recently published a meta-analysis on vitamin C and the length of intensive care unit [ICU] stay [1] and so were interested to read Hill et al's meta-analysis on randomized trials of vitamin C for cardiac surgery patients published in Nutrients in September 2019 [2]. However, we have some methodological concerns.The abstract states that "vitamin C significantly decreased .

…”

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confidence: 99%

“…These dispersion estimates were published by Safaei, however, as standard errors (SE) and not SDs: "All continuous variables are expressed as mean ± standard error of mean" [3] (p. 47) and "Values are mean ± SEM" [3] (Table 2). Thus, the use of SE in Figure 6 led to an erroneous p-value for the vitamin C effect [2]. Hill made the same error (using SE from the Safaei trial) in their meta-analysis on ICU length of stay.…”

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confidence: 99%

See 2 more Smart Citations

Vitamin C for Cardiac Surgery Patients: Several Errors in a Published Meta-Analysis. Comment on “Effects of Vitamin C on Organ Function in Cardiac Surgery Patients: A Systematic Review and Meta-Analysis. Nutrients 2019, 11, 2103”

Hemilä

Chalker

2020

Nutrients

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Overview of oxidative stress and the role of micronutrients in critical illness

Dresen

Pimiento

Patel

et al. 2022

J Parenter Enteral Nutr

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Inflammation and oxidative stress represent physiological response mechanisms to different types of stimuli and injury during critical illness. Its proper regulation is fundamental to cellular and organismal survival and are paramount to outcomes and recovery from critical illness. A proper maintenance of the delicate balance between inflammation, oxidative stress, and immune response is crucial for resolution from critical illness with important implications for patient outcome. The extent of inflammation and oxidative stress under normal conditions is limited by the antioxidant defense system of the human body, whereas the antioxidant capacity is commonly significantly compromised, and serum levels of micronutrients and vitamins significantly depleted in patients who are critically ill. Hence, the provision of antioxidants and anti-inflammatory nutrients may help to reduce the extent of oxidative stress and therefore improve clinical outcomes in patients who are critically ill. As existing evidence of the beneficial effects of antioxidant supplementation in patients who are critically ill is still unclear, actual findings about the most promising anti-inflammatory and antioxidative candidates selenium, vitamin C, zinc, and vitamin D will be discussed in this narrative review. The existing evidence provided so far demonstrates that several factors need to be considered to determine the efficacy of an antioxidant supplementation strategy in patients who are critically ill and indicates the need for adequately designed multicenter prospective randomized control trials to evaluate the clinical significance of different types and doses of micronutrients and vitamins in selected groups of patients with different types of critical illness.

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Effects of Vitamin C on Organ Function in Cardiac Surgery Patients: A Systematic Review and Meta-Analysis

Cited by 35 publications

References 47 publications

Vitamin C may reduce the duration of mechanical ventilation in critically ill patients: a meta-regression analysis

Vitamin C may reduce the duration of mechanical ventilation in critically ill patients: a meta-regression analysis

Vitamin C for Cardiac Surgery Patients: Several Errors in a Published Meta-Analysis. Comment on “Effects of Vitamin C on Organ Function in Cardiac Surgery Patients: A Systematic Review and Meta-Analysis. Nutrients 2019, 11, 2103”

Overview of oxidative stress and the role of micronutrients in critical illness

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