Summary of registered interventional randomised controlled clinical trials of vitamin D (only) in COVID-19
| Trial ID | Scientific title | Nations | Size | Status | Completion date | Aim/description | Primary outcome measures (summarised) |
| NCT 04386850 | Preventive and Therapeutic Effects of Oral 25-Hydroxyvitamin D3 on Coronavirus (COVID-19) in Adults | Iran and USA | 1500 | Recruiting | March 2021 | Two-armed study looking at the effect of 1000 IU of vitamin D in the prevention of COVID-19 in healthcare workers and their families as well as in patients with a COVID-19 diagnosis and treatment of patients with COVID-19 | COVID19 diagnosis, severity, hospitalisation, disease duration, death, oxygen support |
| NCT 04411446 | Randomised Controlled Trial of High Dose of Vitamin D as Compared With Placebo to Prevent Complications Among COVID-19 Patients | Argentina | 1265 | Recruiting | December 2020 | An RCT comparing one dose of 500 000 IU of vitamin D versus placebo in SARS-CoV-confirmed patients requiring hospitalisation for COVID-19 but not critical care at the time of admission. |
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| NCT 04385940 | Improving Vitamin D Status in the Management of COVID-19 | USA | 64 | Not yet recruiting | December 2020 | A double-blind RCT assessing the efficacy of vitamin D (1000 IU daily vs 50 000 IU two times per week for the first week then once weekly) in COVID-19 patients | Symptom recovery over 3-week time period |
| IRCT20200401046909N2 | Investigating Preventive Effects of Oral 25-Hydroxyvitamin D3 on COVID-19 in Adults: a Randomised, Controlled Double-Blind Clinical Trial | Iran | 540 | Recruiting | Not stated | A double-blind RCT on adult participants without COVID-19 to determine the effect of vitamin D supplementation (1000 IU/day) on serum levels of 25(OH)D and relate this to decreased incidence of COVID-19 | Affected by COVID-19 during study (symptoms, CT findings, PCR) |
| NCT 04344041/ EUCTR2020001602-34-FR | COVID-19 and Vitamin D Supplementation: a Multicenter Randomised Controlled Trial of High Dose vs Standard Dose Vitamin D3 in High-risk COVID-19 Patients (CoVitTrial) | France | 260 | Recruiting | May 2021 | Open-labelled randomised study of 400 000 IU of vitamin D as a single dose compared with 50 000 IU of vitamin D in confirmed COVID-19 | Number of death of any cause, during the 14 days following the inclusion and intervention |
| NCT 04334005 | Effect of Vitamin D Administration on Prevention and Treatment of Mild Forms of Suspected COVID-19 | Spain | 200 | Not yet recruiting | June 2020 | An RCT assessing the addition of 25 000 IU of vitamin D in 40–70 year olds who have non-severe symptomatic COVID-19 and who are taking NSAIDs, ACE2 inhibitor, ARB or thiazolidinediones, according to clinician criteria, based on the current recommendations. | Composite of cumulative death (ie, mortality) for all causes and for specific causes |
| EUCTR2020002312-43-ES | Clinical Trial, PHASE III, Randomised, Open-Label, to Evaluate the Efficacy of Administering High-Dose Cholecalciferol Orally Alongside Standard Therapy in Patients with COVID-19 Pneumonia (COVID-19 HUSO) - Efficacy of High Dose Vitamin D in COVID-19 Pneumonia | Spain | 82 | Unknown | Not stated | RCT in vitamin D-deficient (<30 ng/mL) COVID-19 patients with the aim to provide estimates of increased levels of vitamin D levels on days 7 and 14 after high-dose vitamin D treatment (10 000 IU/day) compared with conventional dosing (2000 IU/day) | Increased levels of vitamin D will be determined on days 7 and 14 after initiation of treatment |
| EUCTR2020001960-28-ES | Efficacy of Vitamin D Treatment in Patients Diagnosed with Pneumonia Who Require Hospital Admission and Have Vitamin D Deficiency and a Positive Diagnosis for SARS-CoV-2 (COVID-19) | Spain | 108 | Unknown | Not stated | Randomised controlled blinded trial of vitamin D in COVID-19-positive patients with vitamin D deficiency | Less serious evolution of respiratory syndrome in terms of mortality and ICU admission |
ARB, angiotensin receptor blocker; ICU, intensive care unit; NSAID, non-steroidal anti-inflammatory drug; RCT, randomised controlled trial; SOFA, sequential organ failure assessment.