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STUDY PROTOCOL Open Access

High-dose vitamin D substitution in patients with COVID-19: study protocol for a randomized, double-blind, placebo- controlled, multi-center study—VitCov Trial Fabienne Jaun1* , Maria Boesing1, Giorgia Lüthi-Corridori1, Kristin Abig1, Anja Makhdoomi1, Nando Bloch2, Christina Lins2, Andrea Raess2, Victoria Grillmayr2, Philippe Haas3, Philipp Schuetz4, Luca Gabutti5, Jürgen Muser6, Anne B. Leuppi-Taegtmeyer6, Stéphanie Giezendanner7, Michael Brändle2 and Jörg D. Leuppi1

Abstract

Background: The coronavirus disease 19 (COVID-19) pandemic has caused millions of deaths, and new treatments are urgently needed. Factors associated with a worse COVID-19 prognosis include old age (> 65 years), ethnicity, male sex, obesity, and people with comorbidities. Furthermore, vitamin D deficiency was reported as a predictor of poor prognosis in patients with acute respiratory failure due to COVID-19. According to a recent clinical case series, vitamin D deficiency is a modifiable risk factor, which has the prospect of reducing hospital stay, intensive care, and fatal outcomes. Vitamin D has potent immunomodulatory properties, and its supplementation might improve important outcomes in critically ill and vitamin D-deficient COVID-19 patients. Despite the evidence that supports an association between vitamin D deficiency and COVID-19 severity, there is uncertainty about the direct link. Therefore, the aim of the trial is to assess if high-dose vitamin D supplementation has a therapeutic effect in vitamin D-deficient patients with COVID-19.

Methods: As the trial design, a randomized, placebo-controlled, double-blind, multi-center approach was chosen to compare a high single dose of vitamin D (140,000 IU) followed by treatment as usual (TAU) (VitD + TAU) with treatment as usual only (placebo + TAU) in patients with COVID-19 and vitamin D deficiency.

Discussion: Vitamin D substitution in patients with COVID-19 and vitamin D deficiency should be investigated for efficacy and safety. The study aim is to test the hypothesis that patients with vitamin D deficiency suffering from COVID-19 treated under standardized conditions in hospital will recover faster when additionally treated with high- dose vitamin D supplementation. Latest studies suggest that vitamin D supplementation in patients with COVID-19 is highly recommended to positively influence the course of the disease. With this randomized controlled trial, a contribution to new treatment guidelines shall be made.

Trial registration: ClinicalTrials.gov NCT04525820 and SNCTP 2020-01401

Keywords: Coronavirus, SARS-CoV-2, COVID-19, Vitamin D, Vitamin D deficiency

© The Author(s). 2022 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

* Correspondence: [email protected] 1University Clinic of Medicine, Cantonal Hospital Baselland, Rheinstrasse 26, CH-4410 Liestal, Switzerland Full list of author information is available at the end of the article

Jaun et al. Trials (2022) 23:114 https://doi.org/10.1186/s13063-022-06016-2

Administrative information Note: the numbers in curly brackets in this protocol refer to SPIRIT checklist item numbers. The order of the items has been modified to group similar items (see http://www.equator-network.org/reporting-guidelines/ spirit-2013-statement-defining-standard-protocol-items- for-clinical-trials/).

Title {1} High Dose Vitamin-D-substitution in pa- tients with COVID-19: study protocol for a randomized, double blind, placebo controlled, multi-centre study- VitCov Trial

Trial registration {2a and 2b}. Clinicaltrials.gov: NCT04525820 (from 25.August 2020) SNCTP: 2020-01401

Protocol version {3} Version 3.1 26.07.2021

Funding {4} The study received funding from SWICA AG, Foundation Bank Vontobel, SWF Foundation, Gebro Pharma AG and the by the internal funds of Professor Leuppi.

Author details {5a} Fabienne Jaun, BScN: Co-Investigator, University Clinic of Medicine, Cantonal Hospital Baselland (corresponding author) Maria Boesing: MD, Study Physician University Clinic of Medicine, Cantonal Hospital Baselland and University of Basel Giorgia Lüthi-Corridori, MSc: Co- Investigator, University Clinic of Medi- cine, Cantonal Hospital Baselland and University of Basel Kristin Abig: Co-Investigator, University Clinic of Medicine, Cantonal Hospital Baselland Maria Boesing: MD, Study Physician University Clinic of Medicine, Cantonal Hospital Baselland and University of Basel Anja Makhdoomi: MD, University Clinic of Medicine, Cantonal Hospital Baselland and University of Basel Nando Bloch: MD, Study Phyisician, Cantonal Hospital St. Gallen Christina Lins: MD, Study Phyisician, Cantonal Hospital St. Gallen Andrea Raess. Local Study Coordinator, Cantonal Hospital St. Gallen Victory Grillmayr, Local Study Coordinator, Cantonal Hospital St. Gallen Philippe Haas, MD, PhD, Co- Investigator, Cantonal Hospital Baselland Professor Philipp Schütz, MD: Local Principal Investigator, Cantonal Hospital Aarau and University of Basel Professor Michael Brändle, MD, MSc: Local Principal Investigator, Cantonal Hospital St. Gallen Professor Luca Gabutti, MD: specialist advisor, Cantonal Hospital Bellinzona Jürgen Muser, PhD: specialist advisor,

Administrative information (Continued)

Cantonal Hospital Baselland Prof. Anne B. Leuppi-Taegtmeyer, MD, PhD: Clinical Pharmacologist & Toxicologist, Cantonal Hospital Baselland and University Hospital Basel Stéphanie Giezendanner, PhD: Trial Statistician, Centre for Primary Health Care, University of Basel Professor Michael Brändle, MD, MSc: Local Principal Investigator, Cantonal Hospital St. Gallen Professor Jörg D. Leuppi, MD, PhD: Sponsor, Principal Investigator. University Clinic of Medicine, Cantonal Hospital Baselland and University of Basel

Name and contact information for the trial sponsor {5b}

Prof. Jörg D. Leuppi, MD, PhD Clinical Professor of Internal Medicine, University of Basel Head of the University Clinic of Medicine cantonal hospital Baselland Rheinstrasse 26 CH-4410 Liestal Phone: + 41-61-925-21-80 E-Mail: [email protected]

Role of sponsor {5c} Professor Jörg D. Leuppi and his research group wrote the study protocol together with collaborating partners. The study will be conducted under the supervision of Prof. Leuppi. He and his research team are responsible for all submissions to obtain study approval from local authorities (ethical committee and Swissmedic). Prof. Leuppi is involved in every step of this study including data collection, interpretation of results and writing of scientific reports.

Introduction Background and rationale {6a} A new coronavirus (CoV) infection epidemic began in Wuhan, Hubei, China, in late 2019, originally called 2019-nCoV [1] and renamed COVID-19 by the World Health Organization in 2020. Previous CoV epidemics included severe acute respiratory syndrome (SARS)-CoV in 2003 [2] and Middle East respiratory syndrome (MERS)-CoV in 2012 [3]. The mortality rates were > 10% for SARS and > 35% for MERS [4]. So far, this pandemic is responsible for millions of deaths. The direct cause of death is gen- erally due to ensuing severe atypical pneumonia, followed by acute respiratory distress syndrome (ARDS) [4, 5]. Risk factors for a poor outcome of SARS-CoV-2 infec-

tion have so far been identified to include older age (> 65 years) and comorbidities such as chronic respiratory conditions, hypertension or diabetes, obesity, current

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smoking status, male sex, and Black or Asian ethnic origin [6–9]. Observational studies reported independent associations

between low serum concentrations of 25-hydroxyvitamin D (the major circulating vitamin D metabolite) and sus- ceptibility to acute respiratory tract infection [10–12]. 25- Hydroxyvitamin D supports induction of antimicrobial peptides in response to both viral and bacterial stimuli [6– 8, 13], suggesting a potential mechanism by which vitamin D-inducible protection against respiratory pathogens might be mediated [14]. Previous studies observed that vitamin D deficiency is prevalent among patients with ARDS and other chronic respiratory diseases and likely contributes to its pathogenesis through alveolar-capillary damage [15, 16]. It was further reported that vitamin D is a predictor of poor prognosis in patients with acute re- spiratory failure due to COVID-19 [17–19]. Therefore, leading experts in the field have called for well-powered randomized controlled trials of vitamin D supplementa- tion as an add-on treatment for COVID-19 to test for causality [20]. A randomized placebo-controlled trial of high-dose

vitamin D in critically ill adult patients with vitamin D deficiency found a significant in-hospital mortality re- duction among patients with severe vitamin D deficiency compared to placebo [21]. In a further study of vitamin D status in patients with ARDS, Park and colleagues retrospectively examined data from 108 patients with ARDS for whom a vitamin D status was available; they observed that over 95% of these patients had vitamin D deficiency [22]. When examined according to quartile of serum 25-hydroxyvitamin D, a consistent inverse rela- tionship between serum 25-hydroxyvitamin D and length of hospital and ICU stay among survivors was ob- served [22]. A treatment with vitamin D showed a significant

reduction of inflammatory markers, a shorter time to recovery for patients with cough, gustatory sensory loss in patients with COVID-19, and vitamin D deficiency, without the occurrence of side effects [23, 24]. The an- ticipated risk of side effects due to a single high dose of vitamin D in this study is minimal, compared to the po- tential impact on preventing more extended hospital stays and worse outcomes in COVID-19. A single high dose of vitamin D in addition to smaller daily doses is secure and can be added to the current treatment guide- lines for COVID-19 [23]. Vitamin D supplementation is a safe and cost-effective intervention, with multiple health benefits for patients with COVID-19 and vitamin D deficiency [25].

Objectives {7} The primary objective of this study is to investigate if a single high dose of vitamin D, in addition to

treatment as usual (TAU), reduces the length of the hospital stay in patients with COVID-19 and vitamin D deficiency. Furthermore, we have defined the fol- lowing parameters as secondary outcomes: the neces- sity of ICU treatment, overall mortality, percentage of patients with 25-hydroxyvitamin D > 50 nmol/L (> 20 ng/mL) at day 7, changes in serum calcium, phos- phorus, 25-hydroxyvitamin D, parathyroid hormone (PTH), and the development of sepsis. We hypothe- sized that time to recovery is shorter in the single high-dose vitamin D group relative to the standard treatment group.

Methods: participants, interventions, and outcomes Trial design {8} We decided to conduct the study as a randomized, placebo-controlled, double-blind trial. This study compares a single high dose of vitamin D in addition to treatment as usual (VitD + TAU) to placebo and treatment as usual only (placebo + TAU). Ethically, it is not justifiable not to treat a known vitamin D deficiency. Therefore, we decided to compare the intervention (single high dose of vitamin D) with treatment as usual (smaller daily dose of vitamin D). The study is designed as a superiority study that as- sumes, testing the hypothesis, that a single high dose of vitamin D in addition to TAU leads to faster re- covery than treatment as usual only.

Study setting {9} It is planned to conduct the study in four cantonal hospitals in Switzerland—two in north-western Switzerland, one in the canton of Tessin, and one in eastern Switzerland. All hospitals are category A clinics; two of them are academic. If necessary, other hospitals are asked to participate.

Eligibility criteria {10} Participants are eligible to participate in the study after giving written, informed consent when hospitalized on a general medicine ward due to ongoing, PCR-confirmed SARS-CoV-2 infection, aged ≥18 years with laboratory- confirmed vitamin D deficiency defined as a serum 25- hydroxyvitamin D concentration ≤ 50 nmol/L (≤20 ng/ mL). Patients will be included independently of the se- verity of the disease. The presence of any of the following conditions will lead

to the exclusion of the participant: known hypersensitivity to one of the vitamin D products used in this study or to one of the adjuvants in the drug’s composition, active malignancy, hypercalcemia, granulomatous diseases such as sarcoidosis, history of renal stones within the past year,

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pregnancy/breastfeeding, previous enrolment into the current project, or another interventional trial.

Who will take informed consent? {26a} After a patient is identified as a potential subject, all inclusion criteria are fulfilled, and none of the exclusion criteria is present, the patient will be asked by a study physician if they want to participate in this study. The patient then needs to give his written informed consent before the randomization. The study information and consent form are provided to the patient by the physician, and both documents are revised and approved by the responsible local ethics committee.

Additional consent provisions for collection and use of participant data and biological specimens {26b} It is not planned to collect data or biological material from participants, which is not described or mentioned in the study protocol or patient information. If there are changes in the protocol, participating subjects are provided with a new informed consent form to decide if they want to participate in further investigations.

Interventions Explanation for the choice of comparators {6b} This study will be conducted as a randomized, placebo- controlled, double-blind trial comparing high-dose vita- min D in addition to TAU with placebo + TAU. The recommended supplementation of vitamin D in adults is 800 IU vitamin D3/day [26, 27]. As there is no ethical justification for not

supplementing vitamin D in patients with laboratory- confirmed vitamin D deficiency, we decided against a “placebo only” design. Instead, we will compare single high-dose vitamin D + TAU versus placebo + TAU.

Intervention description {11a}

Intervention group Participants will receive a single oral dose of 140,000 IU of vitamin D3 as an oily solution and then continue with the standard oral dose of 800 IU vitamin D3 per day until discharge. The medication will be administered by instructed personnel—preferably in the morning along with the patients’ other prescribed medication. We did not find information about significant differences resulting from the timing of administration.

Control group Participants will receive a single dose of placebo orally and then continue with the standard dose of 800 IU vitamin D3 per day. The procedure of administration is the same as in the intervention group.

The placebo solution is similar to the product used in the intervention group (VITAMIN D3 Wild Öl 500 IU/ drop) in terms of consistency and look. Neither patients nor physicians can detect a difference between the two products.

Criteria for discontinuing or modifying allocated interventions {11b} Treating doctors can change the dose of vitamin D or stop the treatment if clinically indicated. In such cases, it must be reported to the lead center immediately. The patient will be considered as a dropout. The treating physician can re-evaluate the treatment throughout the trial and independently de- cide about additional treatment options. The patient must be informed about all treatment options and must be treated according to the most recent local or national COVID-19 guidelines.

Strategies to improve adherence to interventions {11c} Patient adherence is not assessed since the participants are all hospitalized, and qualified personnel will administer medication. The nurses and doctors will ensure that the patient receives the study medication correctly. If there is any complication with the administration (e.g., vomiting after taking the study medication), it must be reported directly to the lead center. The local study team will collect the used medication bottles and, if needed, can be used for additional evaluation of adherence after the patient is discharged.

Relevant concomitant care permitted or prohibited during the trial {11d} All treatments or medication considered necessary by treating doctors are permitted, and their use will be recorded in the case report form. There is no restriction in using other treatments or interventions during this trial.

Provisions for post-trial care {30} Patients are carefully followed up until discharge from hospital care. Any after-care necessary due to COVID-19 is organized by the treating physicians and is not connected to this trial. This trial has a mandatory, trial-specific insurance during the whole study period.

Outcomes {12} As the primary outcome, we fixed the length of the hospital stay. Therefore, the measurement will be the overall duration of the hospitalization from enrolment until discharge from hospital care. As defined, to measure the secondary objectives, we will assess if there

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are any differences between the TAU + VitD and the TAU + placebo group in terms of the variables described in the table below.

ICU stay Yes/no

If yes, length of the ICU stays (admission to discharge)

Requirement for mechanical ventilation

Overall mortality

Vitamin D serum concentration

% of patients with 25-(OH)D > 50 nmol/L at day 7

25-(OH)D

Laboratory parameters Calcium

Phosphorus

Parathyroid hormone (PTH)

Sepsis % of patients who develop a sepsis

Complications Complications during the hospitalization due to COVID-19

Vital signs Blood pressure (BP)

Heart rate (HR)

Respiratory rate (RR)

Blood oxygen saturation

Need of oxygen and how much

Quality of life (SF-12 Questionnaire)

At baseline, 28 days, and 3 months after inclusion

Participant timeline {13}

Sample size {14} To calculate the sample size, we looked at an interventional study of vitamin D, which examined the length of hospital stay as an outcome and what is known about the median length of hospital stay in patients hospitalized with COVID-19. A randomized, double- blind, placebo-controlled trial examined the effects of adjunctive vitamin D in adults hospitalized with community-acquired pneumonia (CAP) on time to re- covery [28]. The primary outcome was the complete resolution of chest radiograph infiltrates at 6 weeks post-study treatment. Secondary outcomes included length of hospital stay, intensive care admission, and re- turn to regular activity. At the same time, adjunctive vitamin D did not affect the primary outcome (OR 0.78, 95% CI 0.31 to 1.86, p = 0.548). There was evidence it increased the complete resolution of pneumonia in par- ticipants with baseline vitamin D levels < 25 nmol/L (OR 17.0, 95% CI 1.40–549.45, p = 0.043). Although not sig- nificant, the results indicated that patients in the inter- vention group had shorter length of hospital stay (mean = 3.8, SD = ± 3.1, n = 60) when compared with patients in the placebo group (mean = 4.8, SD = ± 6.5, n = 57),

which indicates a small effect size (Cohen’s d) of 0.1980. The study indicated a 20% reduction in length of hos- pital stay. Considering the above results in the light of COVID-

19, more extended hospital stays in COVID-19 patients are expected. In smaller observational studies describing the clinical course of hospitalized COVID-19 patients in China, a median hospital stay of 12 days (IQR 9–15) (n = 137) [1] or of 10 days (IQR, 7.0–14.0) among those dis- charged alive (n = 47) [29] were observed. Guan et al. presented the clinical characteristics of 1099 patients with laboratory-confirmed COVID-19, and the median length of hospital stay was reported to be 12 days (IQR = 10–14) [30], which we will take as a basis for our sample size calculation. Sample size calculation was performed using the

function “power.t.test” from the R package “stats” with the following parameters [31]: alpha = 0.05, power = 0.80, sigma = 2.96, delta (difference in the primary outcome between intervention and control group) = 2, and alternative hypothesis = two-sided, which resulted in a minimum of 35 patients per group, therefore a total of 70 patients. With a conservatively estimated 10% dropout rate, including the loss to follow-up, and a block size randomization of four, we decided to include 80 patients.

Recruitment {15} After a patient is identified as a potential participant, all inclusion criteria are fulfilled, and none of the exclusion criteria is present, the patient will be asked by their treating physician if they want to participate in this study. Only patients on general wards will be asked. Patients

who are already being treated in the intensive care unit or taking part in another interventional trial will not be considered as potential participants. Neither patients nor doctors will receive financial reimbursement. The study budget will cover expenses for the study medication and diagnostics performed only during this study. The recruitment will take place in the described way in all four centers (cantonal hospital of Baselland in Liestal and Bruderholz, the cantonal hospital of Aarau, the cantonal hospital of St. Gallen, and the regional hospital Lugano). A collaboration with other hospitals in Switzerland will be considered if recruitment is slow.

Assignment of interventions: allocation Sequence generation {16a} Participants will be randomly assigned to either the intervention or the control group in a 1:1 ratio. A statistician not involved in the data analysis generates a randomization list with study group allocation using R [31]. Randomization is carried out stratified by center

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using block randomization with a block size of four to account for differences in standard of care. The randomization master list will be handed over to the university hospital pharmacy in Basel, where the study drug will be labeled and packaged accordingly. In case of an adverse event (AE) or serious adverse event (SAE) that requires an emergency code break, the hospital pharmacy can decode the randomization immediately.

Concealment mechanism {16b} The hospital pharmacy of the university hospital of Basel will pack and label the study medication according to the randomization master list. They will provide the study centers with sealed, identically looking medication packages for each patient that contains either the high- dose vitamin D and the standard medication or the pla- cebo and the standard medication. Participating centers will receive a certain number of blocks of the study drug, which must be used strictly in the ascending order indi- cated by the code.

Implementation {16c} The treating physician will make the enrolment. After a patient has given his/her consent, the physician will take one of the prepared medication packages with the medication. As described above, the assignment to either group will be made randomly.

Assignment of interventions: blinding Who will be blinded {17a} As the hospital pharmacy provides the medication in sealed, identically looking medication packages, neither the treating physician nor the patient or other care providers knows if the patient is in the intervention or placebo group. The statistician will conduct the analysis blinded.

Procedure for unblinding if needed {17b} In case of an event or medical emergency that makes unblinding necessary, the hospital pharmacy can perform a patient-specific unblinding at any time during the study. In such a case, treating doctors can call the pharmacist who has access to the concealed list. Based on the study design and the intervention in this trial, it is assumed that no emergency code break will be neces- sary. In case unblinding becomes necessary, collected pa- tient data will be used for the primary analysis in an intention-to-treat approach, but the analyzing statistician will remain blinded.

Data collection and management Plans for assessment and collection of outcomes {18a} All outcomes are assessed by treating physicians or nurses until discharge or fatality. The CRF is provided

either electronically (Web-based) or in paper form, in which case it will be sent by mail or fax to the coordinating study center, where data will be entered into the Web-based database. The primary outcome is the length of hospital stay.

The exact length will be calculated automatically by the electronic database into which only the date of the admission, the date of inclusion in the study, and the date of discharge must be entered. With this method, copying or calculation errors can be minimized. Patients are screened daily and therefore we will have only a small delay of approximately 1 day from hospital admission until inclusion to the study. Secondary outcomes are the following:

ICU stay Yes/no

If yes, length of the ICU stays (admission to discharge)

Requirement for mechanical ventilation

Overall mortality

Vitamin D serum concentration

% of patients with 25-(OH)D > 50 nmol/L at day 7

25-(OH)D

Laboratory parameters Calcium

Phosphorus

Parathyroid hormone (PTH)

Sepsis % of patients who develop a sepsis

Complications Complications during the hospitalization due to COVID-19

Vital signs BP

HR

RR

Blood oxygen saturation

Need of oxygen and how much

Quality of life (SF-12 Questionnaire)

At baseline, 28 days, and 3months after inclusion

The treating physicians will provide the research team with a copy of all laboratory results (anonymized, with participant identification number)