New Delhi: A new study from Spain suggests that administering high doses of calcifediol — a hormone produced in the liver by vitamin D — can help reduce risk of severe infection in Covid-19 patients and even death.
The study, published in the Journal of Steroid Biochemistry and Molecular Biology by researchers from the University of Córdoba in Spain and research university KU Leuven in Belgium, reveals that calcifediol may have certain advantages over vitamin D3 — the vitamin supplement that is usually prescribed for consumption.
“Vitamin D3 is converted by the liver into calcifediol. However, by directly administering calcifediol instead of vitamin D3, levels of the hormone in the blood are rapidly restored,” José Manuel Quesada Gómez, one of the authors of the study, told ThePrint.
“It also has a more reliable intestinal absorption,” Gómez added. This means the calcifediol is more likely to be absorbed by the body than vitamin D3.
He also said direct administration of calcifediol is more desirable in Covid-19 patients as the CYP2R1 enzyme, which helps convert vitamin D3 to its more useful form, is compromised in many of them.
“Such impaired CYP2R1 activity has been well-demonstrated in patients with chronic obstructive pulmonary disease (a lung-related disease) or asthma. Additionally, calcifediol is more potent when compared to oral Vitamin D3,” Gómez said.
Thus, based on the research, calcifediol should be provided to all Covid-19 patients who have pulmonary or lung-related symptoms, he said.
For the study, 50 Covid-19 patients were given calcifediol along with standard care, involving a regime of hydroxychloroquine and azithromycin. Another 26 patients were only given standard care without the hormone.
Of the 50 patients who received calcifediol, only one was required to be admitted into the intensive care unit (ICU). In comparison, 13 patients or 50 per cent of those who received standard care were admitted to the ICU.
Not a single patient died among those treated with calcifediol and all were discharged without complications at the end of the study period. However, of the 13 patients admitted to the ICU from the standard care group, two died due to the infection.
“Our pilot study demonstrated that administration of a high dose of Calcifediol or, a main metabolite of vitamin D endocrine system, significantly reduced the need for ICU treatment of patients requiring hospitalisation due to proven COVID-19,” the team wrote in the study.
According to Gómez, “Those who suffer from vitamin D deficiency are more likely to benefit from this treatment.”
Experts not convinced by study
However, not all experts are convinced by the study.
Satyajit Rath, a scientist at Indian Institute of Science Education and Research (IISER) in Pune, said while the study is interesting, the results are not definitive.
“It is an extremely small group of patients. It does not identify the degree of severity of Covid-19 in the patients at admission, and does not provide any details of their clinical progress other than ICU admission and death,” Rath told ThePrint.
He also noted that the study did not specify the co-morbidities that the trial patients were suffering from but instead treated all of them as having an equal risk factor, which was not the case. For instance, an obese patient is more likely to succumb to the infection.
The study also does not identify what comorbidities, if any, the patients admitted to the ICU had, Rath pointed out.
“In such a small group, the small differences between the two groups could be enough to skew the results,” he said.
S.P Kalantri, Director-Professor of Medicine from the Mahatma Gandhi Institute of Medical Sciences in Maharashtra, agreed with Rath’s assessment and said that the study had several limitations such as a small sample size. He noted that the randomisation process of the study seemed flawed as well.
“The usual care group had more people with high blood pressure and diabetes — conditions known to adversely affect the outcome of hospitalised Covid patients,” Kalantri told ThePrint.
This means patients in the group that did not receive calcifediol were at higher risk of death than the group that did receive it.
He also noted that the researchers did not measure vitamin D levels before or after administering the hormone. “Thus, we do not know whether the study participants were indeed vitamin D deficient,” he said.
Kalantri also noted that admission to ICU is not a good measure to study disease outcome in trials.
“What matters is progression of disease, measured in most clinical trials by an ordinal scale that asks if the patients required oxygen, high flow nasal oxygen, mechanical ventilation or died,” he said.
The researchers, on their part, acknowledge that the study does not provide definitive answers on whether calcifediol can be beneficial for all Covid-19 patients.
“We are currently conducting a clinical trial with a much larger number of cases to confirm the results of our pilot study,” Gomez said.
This is not the first time that vitamin D has been studied as a possible treatment for Covid-19.
Several studies in the past have suggested that countries that reported low levels of vitamin D deficiency also reported less number of deaths from Covid-19.
Based on computational studies, researchers have shown that the active form of vitamin D, called calcitriol, exhibits significant potent activity against SARS-CoV-2. This led researchers to suggest that vitamin D could help protect against the disease.
A study published in the journal Lancet also highlighted the role of vitamin D in preventing acute respiratory infections.
However, so far, there have been no conclusive clinical trials to confirm the protective role of vitamin D against Covid-19.
While researchers of the Spanish study state that their research is an important entry point to this end, other experts are not too sure.
“The limitations of the study do not help us understand if vitamin D given to all patients with Covid could save lives and reduce serious complications. We need well-designed, robust, larger clinical points with meaningful endpoints to answer this question,” said Kalantri.