Vitamin D deficiency plays major role in hypocalcemia among hospitalized patients with COVID-19: study

Despite the high prevalence of hypocalcemia in patients with COVID-19, very limited studies have been designed to evaluate etiologies of this disorder. The study by Sima Hashemipour et al was designed to evaluate the status of serum parameters involved in calcium metabolism in patients with COVID-19 and hypocalcemia.

Despite some similarities between hypocalcemia in COVID-19 and other critical illnesses, it seems that this disorder is somehow different in COVID-19. Firstly, albeit based on limited studies, hypocalcemia is more prevalent in the acute respiratory syndrome by COVID-19 infection compared to other infections; secondly, hypocalcemia in COVID-19 is not restricted to severe or critical cases and the prevalence of this disorder is high even in non-severe COVID-19.

This cross-sectional study was conducted on 123 hospitalized patients with COVID-19. Serum concentrations of PTH, 25 (OH) D, magnesium, phosphate, and albumin were assessed and compared across three groups of moderate/severe hypocalcemia (serum total calcium<8 mg/dl), mild hypocalcemia (8 mg/dl ≤ serum total calcium< 8.5 mg/ dl) and normocalcemia (serum total calcium≥8.5 mg/dl). Multivariate analyses were performed to evaluate the independent roles of serum parameters in hypocalcemia.

The results of the study were:

• In total, 65.9% of the patients had hypocalcemia.

• Vitamin D deficiency was found in 44.4% and 37.7% of moderate/ severe and mild hypocalcemia cases, respectively, compared to 7.1% in the normal serum total calcium group (P=0.003).

• In multivariate analysis, vitamin D deficiency was independently associated with 6.2 times higher risk of hypocalcemia (P=0.001).

• Only a minority of patients with hypocalcemia had appropriately high PTH (15.1% and 14.3% in mild and moderate/severe hypocalcemia, respectively).

• Serum PTH was low/low-normal in 40.0% of patients with moderate/severe low-corrected calcium group.

• Magnesium deficiency was not associated with hypocalcemia in univariate and multivariate analysis.

In conclusion, the results of the study revealed the significant roles of vitamin D deficiency and the high frequency of functional hypoparathyroidism in the hypocalcemia of COVID-19. Vitamin D deficiency plays a major role in hypocalcemia among hospitalized patients with COVID-19. Inappropriately low/low-normal serum PTH may be a contributing factor in this.

Further reading:

Hypocalcemia in hospitalized patients with COVID 19: roles of hypovitaminosis D and functional hypoparathyroidism

Sima Hashemipour, Somaieh Kiani et al

Journal of Bone and Mineral Metabolism (2022) 40:663–669

https://doi.org/10.1007/s00774-022-01330-w