2.1. Patients
sarcoidosis, SARS-CoV-2 infection, chronic kidney disease, intestinal malabsorption, COVID-19 disease, chronic hepatic dysfunction, lymphomas, kidney stones, hypercalciuria
SARCOIDOSIS, SARS-COV-2 INFECTION, INTESTINAL MALABSORPTION, TUBERCULOSIS, LYMPHOMAS, KIDNEY STONE, SYNDROMES, LOW LEVELS OF VITAMIN D
All patients admitted for the first time to the ICU in the study period were tested with a polymerase chain reaction (PCR) test for SARS-CoV-2 infection upon admission. Patients who had positive PCR test were considered eligible for inclusion in the study if they had a need for invasive or non-invasive respiratory support. All these patients had vitamin D levels measured on admission. Patients with low levels of vitamin D (<50 nmol/L) were included in further study. All patients were older than 18 years and had confirmed COVID-19 disease with PCR test.Non-inclusion criteria included patients with known vitamin D supplementation prior to hospitalization, patients with chronic hepatic dysfunction or intestinal malabsorption syndromes, concomitant use of medication affecting vitamin D metabolism or absorption (anticonvulsants, etc.), elevated serum calcium levels on admission (corrected for albumin concentration), history of hypercalciuria and kidney stones, conditions that could lead to high serum calcium levels (sarcoidosis, tuberculosis, lymphomas), pregnancy or breastfeeding, chronic dialysis, severe chronic kidney disease (estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73 mPatients were excluded from study in case of calcium levels that were consistently above normal serum range (>2.6 mmol/L, >10.5 mg/dL) or if vitamin D levels were >150 nmol/L.