Endocrine Abstracts

Introduction

There is evidence of the interaction between the main parameters of calcium-phosphorus metabolism, vitamin D and the course of a new coronavirus infection. Moreover, hypocalcemia is one of the most frequent biochemical disorders and is associated with severity of the disease, increased likelihood of hospitalization, need for mechanical ventilation, and poor prognosis in COVID-19.

Objective

To estimate the main parameters of calcium-phosphorus metabolism in patients with COVID-19 upon admission to our hospital.

Material and methods

A single-center study was carried out at the Endocrinology Research Centre, Moscow. We included 60 patients (aged ≥ 18 years) with acute respiratory infectious diseases related to COVID-19 (CoV). Baseline biochemical investigations, including serum calcium, phosphate, albumin, 25-hydroxyvitamin D, parathormone, as well as instrumental assessment of the COVID-19 severity were performed before any specific immunotherapy. Statistical analysis was conducted with Statistica 13 (<<StatSoft>>, USA). A p-value of < 0.05 was considered statistically significant.

Results

The prevalence of hypocalcemia (for albumin-adjusted calcium (Ca_adj) < 2.15 mmol/l) and vitamin D deficiency (< 20 ng/ml) was 36.7 and 86.7%, respectively. Lower saturation (SpO2) was observed in patients with the lowest Ca_adj (P = 0.002) and 25(OH) D levels (P = 0.001). Moreover, lower Ca_adj was related to lower values of SpO2 (OR 12 725.213, 95% CI 2.661–60 863.931.6) and vice versa Ca_adj > 2.17 mmol/l was associated with SpO2 > 93% with a probability of 71–92%. In addition, there were no associations between total and albumin-adjusted calcium levels and 25(OH) vitamin D (p1 = 0.061 and p2 = 0.339, respectively). Patients with severe COVID-19 pneumonia (computer tomography (CT) scan grade 3–4) compared with those with less grades (CT 1—2) had significantly lower total Ca and albumin (P < 0.001 for all). In 11.6% of cases, the level of 25(OH)vitamin D was less than 5 ng/ml. Decreased vitamin D levels were associated with higher CRP values (OR 0.892, 95% CI 0.8—0.995) and lower SpO2 (OR 1.227, 95% CI 1.028—1.465). Patients with normal and increased (10 pg/ml or more) IL-6 levels have significant differences in total calcium (2.25 [2.18; 2.38] mmol/l vs 2.15 [2.07; 2.23] mmol/l; P < 0.001) and albumin (44.5 [42; 47] g/l vs 39, 5 [36; 42] g/l; P < 0.001) concentrations.

Conclusion

The hypocalcemia and vitamin D deficiency are highly prevalent in patients with severe course of COVID-19 with the need for hospitalization. Further research is required to determine the impact of impaired calcium-phosphorus metabolism on COVID-19 to develop the optimal therapeutic strategies.