Association of Oral or Intravenous Vitamin C Supplementation with Mortality: A Systematic Review and Meta-Analysis
Luz Fernandez, Carol Johnston, Andrea Fabbri, Chongxi Xu, Tong Yi, Siwen Tan, Hui Xu, Yu Hu, Junpeng Ma, Jianguo Xu
doi:10.3390/nu15081848
Mortality is the most clinically serious outcome, and its prevention remains a constant struggle. This study was to assess whether intravenous or oral vitamin C (Vit-C) therapy is related to reduced mortality in adults. Data from Medline, Embase, and the Cochrane Central Register databases were acquired from their inception to 26 October 2022. All randomized controlled trials (RCTs) involving intravenous or oral Vit-C against a placebo or no therapy for mortality were selected. The primary outcome was all-cause mortality. Secondary outcomes were sepsis, COVID-19, cardiac surgery, noncardiac surgery, cancer, and other mortalities. Forty-four trials with 26540 participants were selected. Although a substantial statistical difference was observed in all-cause mortality between the control and the Vit-C-supplemented groups (p = 0.009, RR 0.87, 95% CI 0.78 to 0.97, I 2 = 36%), the result was not validated by sequential trial analysis. In the subgroup analysis, mortality was markedly reduced in Vit-C trials with the sepsis patients (p = 0.005, RR 0.74, 95% CI 0.59 to 0.91, I 2 = 47%), and this result was confirmed by trial sequential analysis. In addition, a substantial statistical difference was revealed in COVID-19 patient mortality between the Vit-C monotherapy and the control groups (p = 0.03, RR 0.84, 95% CI 0.72 to 0.98, I 2 = 0%). However, the trial sequential analysis suggested the need for more trials to confirm its efficacy. Overall, Vit-C monotherapy does decrease the risk of death by sepsis by 26%. To confirm Vit-C is associated with reduced COVID-19 mortality, additional clinical random control trials are required.
Conflicts of Interest: The authors declare no conflict of interest. Study Registration: Prospero registration number CRD42022369724.
References
Aisa-Alvarez, Soto, Guarner-Lans, Camarena-Alejo, Franco-Granillo et al., Usefulness of antioxidants as adjuvant therapy for septic shock: A randomized clinical trial, Medicina, 
doi:10.3390/medicina56110619Alexander, Wilkes, Schroeder, Buettner, Wagner et al., Pharmacologic ascorbate reduces radiation-induced normal tissue toxicity and enhances tumor radiosensitization in pancreatic cancer, Cancer Res, 
doi:10.1158/0008-5472.CAN-18-1680Antonic, Lipovec, Gregorcic, Juric, Kosir, Perioperative ascorbic acid supplementation does not reduce the incidence of postoperative atrial fibrillation in on-pump coronary artery bypass graft patients, J. Cardiol
Ap, Daga, Mawari, Koner, Singh et al., Effect of Supplementation of Vitamin C and Thiamine on the Outcome in Sepsis: South East Asian Region, J. Assoc. Physicians India
Bailey, Raman, Mceneny, Young, Parham et al., Vitamin C prophylaxis promotes oxidative lipid damage during surgical ischemia-reperfusion, Free Radic. Biol. Med, 
doi:10.1016/j.freeradbiomed.2005.09.024Bjordahl, Helmer, Gosnell, Wemmer, O'hara et al., Perioperative supplementation with ascorbic acid does not prevent atrial fibrillation in coronary artery bypass graft patients, Am. J. Surg
Block, Mead, Vitamin C in Alternative Cancer Treatment: Historical Background, Integr. Cancer Ther
Brok, Thorlund, Gluud, Wetterslev, Trial sequential analysis reveals insufficient information size and potentially false positive results in many meta-analyses, J. Clin. Epidemiol, 
doi:10.1016/j.jclinepi.2007.10.007Cameron, Pauling, Supplemental ascorbate in the supportive treatment of cancer: Reevaluation of prolongation of survival times in terminal human cancer, Proc. Natl. Acad. Sci, 
doi:10.1073/pnas.75.9.4538Coppock, Violet, Vasquez, Belden, Foster et al., Pharmacologic Ascorbic Acid as Early Therapy for Hospitalized Patients with COVID-19: A Randomized Clinical Trial, Life, 
doi:10.3390/life12030453Cortés-Jofré, Rueda, Asenjo-Lobos, Madrid, Bonfill Cosp, Drugs for preventing lung cancer in healthy people, Cochrane Database Syst. Rev, 
doi:10.1002/14651858.CD002141.pub3Creagon, Moertel, O'fallon, Schutt, O'connell et al., Failure of high-dose vitamin C (ascorbic acid) therapy to benefit patients with advanced cancer. A controlled trial, N. Engl. J. Med, 
doi:10.1056/NEJM197909273011303Dachs, Gandhi, Wohlrab, Carr, Morrin et al., Vitamin C Administration by Intravenous Infusion Increases Tumor Ascorbate Content in Patients with Colon Cancer: A Clinical Intervention Study, Front. Oncol, 
doi:10.3389/fonc.2020.600715Darban, Malek, Memarian, Gohari, Kiani et al., Efficacy of high dose Vitamin C, melatonin and zinc in Iranian patients with acute respiratory syndrome due to coronavirus infection: A pilot randomized trial, J. Cell. Mol. Anesth, 
doi:10.22037/jcma.v6i2.32182Das, Sen, Goswami, Effect of Vitamin C on adrenal suppression by etomidate induction in patients undergoing cardiac surgery: A randomized controlled trial, Ann. Card. Anaesth, 
doi:10.4103/0971-9784.185522Donovan, Prophylaxis to Reduce Postoperative Atrial Fibrillation in Cardiac Surgery
Duffy, O'kane, Stevenson, Young, Harkin et al., A randomized clinical trial of ascorbic acid in open abdominal aortic aneurysm repair, Intensive Care Med. Exp, 
doi:10.1186/s40635-015-0050-5El Driny, Esmat, Shaheen, Sabri, Efficacy of High-Dose Vitamin C Infusion on Outcomes in Sepsis Requiring Mechanical Ventilation: A Double-Blind Randomized Controlled Trial, Anesthesiol. Res. Pract, 
doi:10.1155/2022/4057215Emadi, Nemati, Ghorbani, Allahyari, The effect of high-dose vitamin c on biochemical markers of myocardial injury in coronary artery bypass surgery, Braz. J. Cardiovasc. Surg, 
doi:10.21470/1678-9741-2018-0312Ferrón-Celma, Mansilla, Hassan, Garcia-Navarro, Comino et al., Effect of Vitamin C Administration on Neutrophil Apoptosis in Septic Patients After Abdominal Surgery, J. Surg. Res, 
doi:10.1016/j.jss.2008.04.024Fong, Au, Ng, Steroid, ascorbic acid, and thiamine in adults with sepsis and septic shock: A systematic review and component network meta-analysis, Sci. Rep, 
doi:10.1038/s41598-021-95386-9Fowler, Syed, Knowlson, Sculthorpe, Farthing et al., Phase I safety trial of intravenous ascorbic acid in patients with severe sepsis, J. Transl. Med
Fowler, Truwit, Hite, Morris, Dewilde et al., Effect of Vitamin C Infusion on Organ Failure and Biomarkers of Inflammation and Vascular Injury in Patients with Sepsis and Severe Acute Respiratory Failure: The CITRIS-ALI Randomized Clinical Trial, J. Am. Med. Assoc, 
doi:10.1001/jama.2019.11825Granger, Eck, Dietary Vitamin C in Human Health
Greenlee, Kwan, Kushi, Song, Castillo et al., Antioxidant supplement use after breast cancer diagnosis and mortality in the Life after Cancer Epidemiology (LACE) cohort, Cancer, 
doi:10.1002/cncr.26526Habib, Ahmed, Early Adjuvant Intravenous Vitamin C Treatment in Septic Shock may Resolve the Vasopressor Dependence, Int. J. Microbiol. Adv. Immunol, 
doi:10.19070/2329-9967-1700015Hoffer, Robitaille, Zakarian, Melnychuk, Kavan et al., High-dose intravenous vitamin C combined with cytotoxic chemotherapy in patients with advanced cancer: A phase I-II clinical trial, PLoS ONE, 
doi:10.1371/journal.pone.0120228Hu, Yuan, Wang, Li, Cai et al., Efficacy and safety of vitamin C for atrial fibrillation after cardiac surgery: A meta-analysis with trial sequential analysis of randomized controlled trials, Int. J. Surg, 
doi:10.1016/j.ijsu.2016.12.009Jahan, Ahmad, Ali, Effect of ascorbic acid in the treatment of tetanus, Bangla-Desh Med. Res. Counc. Bull
Jamalimoghadamsiahkali, Zarezade, Koolaji, Seyedalinaghi, Zendehdel et al., Safety and effectiveness of high-dose vitamin C in patients with COVID-19: A randomized open-label clinical trial, Eur. J. Med. Res, 
doi:10.1186/s40001-021-00490-1Jiang, Efficacy of intravenous vitamin C intervention for septic patients: A systematic review and meta-analysis based on randomized controlled trials, Am. J. Emerg. Med, 
doi:10.1016/j.ajem.2021.08.012Jung, Lee, Baek, Kim, Vitamin C for ≥5 days is associated with decreased hospital mortality in sepsis subgroups: A nationwide cohort study, Crit. Care, 
doi:10.1186/s13054-021-03872-3Kassem, Ahmed, Omran, Megahed, Habib, Role of ascorbic acid infusion in critically ill patients with transfusion-related acute lung injury, Br. J. Clin. Pharmacol, 
doi:10.1111/bcp.15167Knodell, Tate, Akl, Wilson, Vitamin C prophylaxis for posttransfusion hepatitis: Lack of effect in a controlled trial, Am. J. Clin. Nutr, 
doi:10.1093/ajcn/34.1.20Kumari, Dembra, Dembra, Bhawna, Gul et al., The Role of Vitamin C as Adjuvant Therapy in COVID-19, Cureus, 
doi:10.7759/cureus.11779Lamontagne, Masse, Menard, Sprague, Pinto et al., Intravenous Vitamin C in Adults with Sepsis in the Intensive Care Unit, N. Engl. J. Med, 
doi:10.1056/NEJMoa2200644Li, Zeng, Li, Yang, Wang et al., None
Lin, Cook, Albert, Zaharris, Gaziano et al., Vitamins C and E and beta carotene supplementation and cancer risk: A randomized controlled trial, J. Natl. Cancer Inst, 
doi:10.1093/jnci/djn438Mahmoodpoor, Shadvar, Sanaie, Hadipoor, Pourmoghaddam et al., Effect of Vitamin C on mortality of critically ill patients with severe pneumonia in in-tensive care unit: A preliminary study, BMC Infect. Dis, 
doi:10.1186/s12879-021-06288-0Majidi, Rabbani, Gholami, Gholamalizadeh, Bourbour et al., The Effect of Vitamin C on Pathological Parameters and Survival Duration of Critically Ill Coronavirus Disease 2019 Patients: A Randomized Clinical Trial, Front. Immunol, 
doi:10.3389/fimmu.2021.717816Moertel, Fleming, Creagan, Rubin, O'connell et al., High-Dose Vitamin C versus Placebo in the Treatment of Patients with Advanced Cancer Who Have Had No Prior Chemotherapy, N. Engl. J. Med
Mohamed, Prasannan, Moni, Edathadathil, Prasanna et al., Vitamin c therapy or routine care in septic shock (ViCTOR) trial: Effect of intravenous vitamin C, thiamine, and hydrocortisone administration on inpatient mortality among patients with septic shock, Indian J. Crit. Care Med, 
doi:10.5005/jp-journals-10071-23517Muralidar, Ambi, Sekaran, Krishnan, The emergence of COVID-19 as a global pandemic: Understanding the epidemiology, immune response and potential therapeutic targets of SARS-CoV-2, Biochimie, 
doi:10.1016/j.biochi.2020.09.018Niu, Qin, Yang, Fan, Liu et al., Effects of early vitamin C supplementation on the prognosis of patients with sepsis, Chin. J. Mod. Med
Olczak-Pruc, Swieczkowski, Ladny, Pruc, Juarez-Vela et al., Vitamin C Supplementation for the Treatment of COVID-19: A Systematic Review and Meta-Analysis, Syst. Rev. Meta-Anal
Ozgunay, Ceylan, Ökmen, Sayan, Eminoglu et al., The use of vitamin C in the intensive care unit during the COVID-19 pandemic, Eur. Res. J, 
doi:10.18621/eurj.938778Rawat, Roy, Maitra, Gulati, Khanna et al., Vitamin C and COVID-19 treatment: A systematic review and meta-analysis of randomized controlled trials, Diabetes Metab. Syndr. Clin. Res. Rev, 
doi:10.1016/j.dsx.2021.102324Razmkon, Sadidi, Sherafat-Kazemzadeh, Mehrafshan, Jamali et al., Administration of vitamin C and vitamin E in severe head injury: A randomized double-blind controlled trial, Clin. Neurosurg
Reddy, Samavedam, Aluru, Yelle, Rajyalakshmi, Metabolic resuscitation using hydrocortisone ascorbic acid thiamine: Do individual components influence reversal of shock independently? Indian, J. Crit. Care Med, 
doi:10.5005/jp-journals-10071-23515Rosengrave, Spencer, Williman, Mehrtens, Morgan et al., Intravenous vitamin C administration to patients with septic shock: A pilot randomised controlled trial, Crit. Care
Samir Bazan, Hesham El-Sherazy, Mahmoud Shaheen, Sabri, Impact of ascorbic acid in reducing the incidence of vancomycin associated nephrotoxicity in critically ill patients: A preliminary randomized controlled trial, F1000Research, 
doi:10.12688/f1000research.55619.1Spargias, Alexopoulos, Kyrzopoulos, Iacovis, Greenwood et al., Ascorbic acid prevents contrast-mediated nephropathy in patients with renal dysfunction undergoing coronary angiography or intervention, Circulation, 
doi:10.1161/01.CIR.0000146396.19081.73Sterne, Savović, Page, Elbers, Blencowe et al., RoB 2: A revised tool for assessing risk of bias in randomised trials, BMJ, 
doi:10.1136/bmj.l4898Tanaka, Matsuda, Miyagantani, Yukioka, Matsuda et al., Reduction of resuscitation fluid volumes in severely burned patients using ascorbic acid administration: A randomized, prospective study, Arch. Surg, 
doi:10.1001/archsurg.135.3.326Tehrani, Yadegarynia, Abrishami, Moradi, Gharaei et al., An investigation into the Effects of Intravenous Vitamin C on Pulmonary CT Findings and Clinical Outcomes of Patients with COVID 19 Pneumonia A Randomized Clinical Trial, Urol. J, 
doi:10.22037/uj.v18i.6863Ter Riet, Kessels, Knipschild, Randomized clinical trial of ascorbic acid in the treatment of pressure ulcers, J. Clin. Epidemiol, 
doi:10.1016/0895-4356(95)00053-4Thomas, Patel, Bittel, Wolski, Wang et al., Effect of High-Dose Zinc and Ascorbic Acid Supplementation vs Usual Care on Symptom Length and Reduction among Ambulatory Patients with SARS-CoV-2 Infection: The COVID A to Z Randomized Clinical Trial, JAMA Netw. Open, 
doi:10.1001/jamanetworkopen.2021.0369Tian, Chen, Liu, Chen, Liu et al., Comparative efficacy of combination of 1L polyethylene glycol, castor oil and ascorbic acid versus 2L polyethylene glycol plus castor oil versus 3L polyethylene glycol for colon cleansing before colonoscopy: Study protocol of a randomized, double-blind, single-center study, Medicine, 
doi:10.1097/MD.0000000000010481Vandervelden, Wauters, Breuls, Fieuws, Vanhove et al., Early administration of Vitamin C in patients with sepsis or septic shock in emergency departments: A multicenter, double blinded, randomized controlled trial: The C-EASIE trial protocol, PLoS ONE, 
doi:10.1371/journal.pone.0259699Verrax, Calderon, Pharmacologic concentrations of ascorbate are achieved by parenteral administration and exhibit antitumoral effects, Free Radic. Biol. Med, 
doi:10.1016/j.freeradbiomed.2009.02.016Wacker, Burton, Berger, Hegg, Heisdorffer et al., Evaluating Vitamin C in Septic Shock: A Randomized Controlled Trial of Vitamin C Monotherapy, Crit. Care Med, 
doi:10.1097/CCM.0000000000005427Wang, Wang, Zhang, Zhu, Zhang et al., Effect of intravenous injection of vitamin c on postoperative pulmonary complications in patients undergoing cardiac surgery: A double-blind, randomized trial, Drug Des. Devel. Ther, 
doi:10.2147/DDDT.S254150Wilson, Mechanism of action of vitamin C in sepsis: Ascorbate modulates redox signaling in endothelium, BioFactors, 
doi:10.1002/biof.7Yanase, Bitker, Hessels, Osawa, Naorungroj et al., Blind, Randomized, Controlled Trial of High-Dose Intravenous Vitamin C for Vasoplegia after Cardiac Surgery, J. Cardiothorac. Vasc. Anesth, 
doi:10.1053/j.jvca.2019.08.034Yeom, Lee, Park, Yu, Park et al., High dose concentration administration of ascorbic acid inhibits tumor growth in BALB/C mice implanted with sarcoma 180 cancer cells via the restriction of angiogenesis, J. Transl. Med, 
doi:10.1186/1479-5876-7-70Zabet, Mohammadi, Ramezani, Khalili, Effect of high-dose Ascorbic acid on vasopressor s requirement in septic shock, J. Res. Pharm. Pract, 
doi:10.4103/2279-042x.179569Zhang, Rao, Li, Zhu, Liu et al., Pilot trial of high-dose vitamin C in critically ill COVID-19 patients, Ann. Intensive Care, 
doi:10.1186/s13613-020-00792-3