Synergistic Effect of Quercetin and Vitamin C Against COVID-19: Is a Possible Guard for Front Liners
et al., SSRN, doi:10.2139/ssrn.3682517, NCT04377789, Nov 2020
Small prophylaxis RCT with 113 patients showing fewer cases with quercetin + vitamin C + bromelain prophylaxis. Note that this paper disappeared from SSRN without explanation.
This paper has multiple data issues:
Impossible follow-up duration: the text states the study follow-up period was 'between March 20 and June 20' - 92 days. However, the reported average follow-up periods are 113 days for the QCB group and 118 days for the control group. Furthermore, the Kaplan-Meier plot's X-axis terminates at ~85 days.
Invalid Cox regression confidence intervals: in the Cox proportional risk model table, the 95% confidence intervals for age and sex are mathematically impossible, with the lower bounds greater than the upper bounds. For age, the interval does not contain the point estimate.
Kaplan-Meier plot contradicts data: the Kaplan-Meier plot in Figure 2 displays a minimum cumulative survival of roughly 0.96 for the control group. However, with 9 events out of 42 participants, the survival should be lower.
Imbalanced randomization and baseline imbalance: the study claims simple randomization, but the group sizes are severely imbalanced (71 vs 42) without a stated allocation ratio. Furthermore, the baseline age is significantly different (p=0.001) between the groups (39.0 vs 32.9 years).
Cox model complete separation error: Table 2 shows zero COVID-19 cases had previous coexisting diseases. Including 'chronic disease' as a covariate in the Cox model results in a reported HR of 0.0 with a CI of 0.0-0.0, indicating complete separation.
Contradictory flowchart and text counts: the abstract and methods text state that 113 healthcare professionals accepted and were randomized (71 QCB, 42 control). However, Figure 1 shows 118 were randomized (73 QCB, 45 Control), with subsequent exclusions leading to the 71 and 42 analyzed. The text inaccurately labels this as 'intention-to-treat'.
Trial registration date: the text claims the study was registered at ClinicalTrials.gov on 'March 20nd 2020'. However, the identifier NCT04377789 (history) belongs to a trial posted in May 2020, meaning the study was retrospectively registered.
No ITT analysis: the study claims an 'intention-to-treat' analysis was performed on 113 patients, but the flow diagram shows 118 were randomized and 5 were excluded post-randomization.
Inconsistent Table 1 categories: In Table 1, under 'previous coexisting disease', the QCB group has 'None' = 54, but also has an '-Other' row reporting 53, which contradicts the 'None' count.
This study is excluded in meta-analysis:
paper no longer available at the source, and the contact does not reply to queries; multiple data issues - pending author response.
Study covers quercetin and vitamin C.
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risk of case, 91.7% lower, RR 0.08, p = 0.03, treatment 1 of 71 (1.4%), control 9 of 42 (21.4%), NNT 5.0, adjusted per study, inverted to make RR<1 favor treatment.
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| Effect extraction follows pre-specified rules prioritizing more serious outcomes. Submit updates |
Arslan et al., 16 Nov 2020, Randomized Controlled Trial, Turkey, preprint, 7 authors, study period 20 March, 2020 - 31 August, 2020, this trial uses multiple treatments in the treatment arm (combined with vitamin C and bromelain) - results of individual treatments may vary, trial NCT04377789 (history).
Abstract: 1
Synergistic Effect of Quercetin and Vitamin C Against COVID-19: Is A Possible Guard
for Front liners?
Bengu Arslan1, Nurcan Ucuncu Ergun1, Seyma Topuz1, Seda Yilmaz Semerci2, Nurettin
Suner3, Ali Kocatas4, Hasan Onal1
1Istanbul
Kanuni Sultan Suleyman Training and Research Hospital, Department of Pediatric
Nutrition and Metabolism Clinics, Istanbul, Turkey
2Istanbul
Kanuni Sultan Suleyman Training and Research Hospital, Department of
Neonatology, Istanbul, Turkey
3Istanbul
Kanuni Sultan Suleyman Training and Research Hospital, Department of General
Medicine, Istanbul, Turkey
4Istanbul
Kanuni Sultan Suleyman Training and Research Hospital, Departmento f General
Surgery, Istanbul, Turkey
Bengu Arslan, Postdoctorate Fellow of Pediatric Nutrition and Metabolism, Istanbul Kanuni
Sultan
Suleyman
Training
and
Research
Hospital,
Department
of
Pediatrics,
Istanbul/TURKEY
Nurcan Ucuncu Ergun, Postdoctorate Fellow of Pediatric Nutrition and Metabolism, Istanbul
Kanuni Sultan Suleyman Training and Research Hospital, Department of Pediatrics,
Istanbul/TURKEY
Seyma Topuz, Nutritionist, Istanbul Kanuni Sultan Suleyman Training and Research Hospital,
Department of Pediatric Nutrition and Metabolism, Istanbul/TURKEY
Seda Yılmaz Semerci, Neonatalogist, Istanbul Kanuni Sultan Suleyman Training and Research
Hospital, Division of Neonatology, Istanbul/TURKEY
Nurettin Suner, Medical Doctor, Istanbul Kanuni Sultan Suleyman Training and Research
Hospital, Division of General Medicine, Istanbul/TURKEY
This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=3682517
2
Ali Kocatas, Professor of General Surgery, Istanbul Kanuni Sultan Suleyman Training and
Research Hospital, Department of General Surgery, Administrator/Director of Hospital,
Istanbul/TURKEY
Hasan Onal, Professor of Pediatrics, Istanbul Kanuni Sultan Suleyman Training and Research
Hospital, Chief of Pediatric Nutrition and Metabolism Department, Istanbul/TURKEY
Running title: Quercetin and Vitamin C Supplement Against COVID-19
*Corresponding
author: Hasan Onal, MD
Word Count: 1835
Number of Figures: 2
Number of Tables: 3
Turgut Özal Bulvarı No: 1, 34303 Ataşehir
Küçükçekmece, İstanbul / TURKEY
Tel: +90 532 509 29 88; Fax: 0 212 571 47 90
E-mail: hasanonal@hotmail.com
ORCID ID: https://orcid.org/0000-0001-9676-7086
This preprint research paper has not been peer reviewed. Electronic copy available at: https://ssrn.com/abstract=3682517
3
Summary
Background While waiting for vaccine, hygiene measures, social distance and personal
protective equipment are the only basic protection against Novel Coronavirus. However, these
are not sufficient to protect healthcare workers.This study aimed to evaluate if quercetin and
vitamin C could be protective against Novel Coronavirus.
Methods In prophylaxis group supplementation containing 500mg of quercetin, 500mg of
vitamin C and 50mg of bromelain (QCB) was initiated daily in 2 divided doses for 71
healthcare workers working in areas with high risk of COVID-19, whereas 42 were determined
as control group without using supplements.A maximum period of follow-up was determined
as 120 days.Termination of use of QCB earlier or having a Coronavirus infection was
considered as final point.At the end rapid diagnostic test used to detect immunoglobulin
positivity.
Results A total of 113 persons included. No significant difference detected between groups in
terms of other features.Mean age of..
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arslan