Effect of a Single High-Dose Vitamin D3 on the Length of Hospital Stay of Severely 25-Hydroxyvitamin D-Deficient Patients with COVID-19

OBJECTIVES: In this ancillary analysis of a multicenter, double-blinded, randomized, placebo-controlled trial, we investigated the effect of a single high dose of vitamin D3 on the length of hospital stay of patients with severe 25-hydroxyvitamin D deficiency and COVID-19. METHODS: The primary outcome was length of hospital stay, defined as the total number of days that patients remained hospitalized from the date of randomization until the date of hospital discharge. Secondary outcomes included serum levels of 25-hydroxyvitamin D, mortality during hospitalization, number of patients admitted to the intensive care unit, and number of patients who required mechanical ventilation. ClinicalTrials.gov: NCT04449718. RESULTS: Thirty-two patients were included in the study. The mean (SD) age was 58.5 (15.6) years, body mass index was 30.8 (8.6) kg/m2, and 25-hydroxyvitamin D level was 7.8 (1.6) ng/mL. No significant difference was observed in the median interquartile range of length of hospital stay between the vitamin D3 group (6.0 [4.0-18.0] days) versus placebo (9.5 [6.3-15.5] days) (log-rank p=0.74; hazard ratio, 1.13 [95% confidence interval (CI), 0.53-2.40]; p=0.76). Vitamin D3 significantly increased serum 25-hydroxyvitamin D levels in the vitamin D3 group compared with that in the placebo group (between-group difference, 23.9 ng/mL [95% CI, 17.7-30.1]; p<0.001). CONCLUSIONS: A dose of 200.000 IU of vitamin D3 did not significantly reduce the length of hospital stay of patients with severe 25-hydroxyvitamin D deficiency and COVID-19.


' INTRODUCTION
Vitamin D has potent antimicrobial effects, which may modulate the immune system (1) and protect against respiratory diseases (2). Hospitalized patients with COVID-19 may present with low levels of 25-hydroxyvitamin D [25(OH)D] (3,4). However, the role of vitamin D in the management of COVID-19 remains controversial (3,5,6). We recently showed that a single high dose of vitamin D 3 versus placebo did not significantly reduce the length of hospital stay among hospitalized patients with moderate to severe COVID-19 and either normal (430 ng/mL) or reduced levels of 25(OH)D (o20 ng/mL) (7). However, in a subsequent cohort study, we observed that COVID-19 patients with 25(OH)D levels o10 ng/mL showed a trend (p=0.057) of longer length of hospital stay than those with 25 (OH)D levels X10 ng/mL (95% confidence interval [CI]: 6.4-11.6 days versus 6.6-7.4 days) (8).
Herein, we report on an ancillary analysis of our randomized clinical trial (7)  Copyright & 2021 CLINICS -This is an Open Access article distributed under the terms of the Creative Commons License (http://creativecommons.org/licenses/by/ 4.0/) which permits unrestricted use, distribution, and reproduction in any medium or format, provided the original work is properly cited.
No potential conflict of interest was reported.
de São Paulo (a quaternary referral teaching hospital) and from the Ibirapuera Field Hospital, both located in São Paulo, Brazil. All patients were diagnosed with COVID-19 via polymerase chain reaction testing at the time of enrollment or using a serological assay (ELISA) to detect IgG against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The primary outcome was length of hospital stay, defined as the total number of days that patients remained hospitalized from the date of randomization until the date of hospital discharge. Secondary outcomes included serum levels of 25(OH)D, mortality during hospitalization, number of patients admitted to the intensive care unit, and number of patients who required mechanical ventilation.
The protocol followed the Declaration of Helsinki and local regulations and was approved by the National and Institutional Ethical Committee of the Hospital das Clínicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil. Written informed consent was obtained from each participant prior to enrollment. This manuscript has been reported according to the CONSORT guidelines. Further details on patient recruitment, supplementation protocol and blindness, procedures, and outcomes can be found elsewhere (7).
The log-rank test was used to compare the Kaplan-Meier estimate curves for length of hospital stay, with deaths being right-censored in the analysis. A Cox regression model was used to estimate the hazard ratio (HR) with corresponding two-sided 95% CIs. Generalized estimating equations for repeated measures were used to test possible differences in 25(OH)D levels. Statistical analyses were performed using the IBM-SPSS software, version 20.0. The significance level was set at two-sided a=0.05.
There was no significant difference in the median (interquartile range [IQR]) length of hospital stay between the vitamin D 3 group (6.0 [4.0-18.0] days) versus placebo (9.5 [6.3-15.5] days) (log-rank p=0.74; HR for hospital discharge, 1.13 [95% CI, 0.53-2.40]; p=0.76) (Figure 1). Importantly, the number of patients with a length of hospital stay o7 [the median time observed in the entire cohort of patients (7)   There was no in-hospital mortality in the vitamin D 3 group versus one death (6.3%) in the placebo group (p40.99).

' DISCUSSION
In this ancillary analysis including a subset of patients with moderate to severe COVID-19 and severe 25(OH)D deficiency, we showed that a single high dose of 200.000 IU of vitamin D 3 resulted in an approximate four-fold increase in 25(OH)D levels but did not significantly reduce length of hospital stay, mortality, admission to intensive care unit, mechanical ventilation requirement, or other clinical outcomes. Despite the well-recognized role of vitamin D in the immune system (1), findings from observational studies are   controversial concerning the association between vitamin D deficiency and COVID-19 severity (3,5). In addition, a recent systematic review including randomized controlled trials did not collate sufficient evidence to conclude that vitamin D supplementation benefits COVID-19 patients (10). In the current study, the wide CIs for HR regarding length of hospital stay suggest that some patients may have benefited from the intervention, a hypothesis that needs to be tested by larger clinical trials involving severely 25(OH)D-deficient patients. The strengths of this study include its randomized, controlled, double-blinded design, confirmation of the ability of the supplementation protocol to raise 25(OH)D levels, and assessment of patients before vaccination, which could be an important confounder affecting the clinical outcomes.
The limitations of this study were the small sample size, considering that this trial was not planned to evaluate severely 25(OH)D-deficient patients only, and the long time that elapsed from symptom onset to vitamin D 3 administration (i.e., 8.6 days), which could mask potential early benefits evoked by this intervention.

' CONCLUSION
A dose of 200.000 IU of vitamin D 3 did not significantly reduce the length of hospital stay of hospitalized patients with COVID-19 presenting with severe 25(OH)D deficiency, although there was great heterogeneity in the responses likely associated with the low sample size. Further trials are warranted to test the efficacy of vitamin D 3 supplementation, particularly as a pre-or post-exposure prophylaxis strategy, in patients with COVID-19 and severe 25(OH)D deficiency.