Serum Ionized Calcium Levels May Be More Closely Related To The Admission Qtc Interval Than Total Calcium Levels In Patients Hospitalized With Covid-19

Özet

Hypocalcemia prolongs the QTc interval. Total calcium (TCa) measurement can be misleading in cases where theconcentration of albumin is abnormal. We aimed to investigate which calcium level—ionized calcium (iCa) or TCa—maybe more closely related to the QTc interval in COVID-19 patients in whom hypocalcemia and hypoalbuminemia areobserved frequently.Adult patients hospitalized for COVID-19 were included in this study. ICa levels were obtained from the venous blood gassample examined during the emergency department admission, and the TCa levels were obtained from the biochemistryresults on admission. The pH-adjusted iCa (Corrected-iCa) and albumin-adjusted TCa (corrected-TCa) were calculated. TheQT interval was measured from the admission ECG and corrected for heart rate using the Bazett formula.Hundred and thirty-two patients were included in the study. The mean age was 50±19 years, and 62 (47%) patients werefemale. Median iCa level was 1,13 mmol/L (1,08-1,18 interquartile range (IQR)), median TCa level was 2.13 mmol/L (2.02 -2.22 IQR). 76 patients (57%) had hypocalcemia (iCa<1,16 mmol/L). The median QTc interva l was 431 ms (414-450 IQR).In the multivariable linear regression analysis, a significant relationship was observed between the QTc interval and iCaand corrected-iCa levels (β=-2.22, standard error (SE) =27.839, p=0.028, β=-2.16, SE=29.407, p=0.033), but no significantrelationship was observed between TCa and corrected-TCa levels (β=-1.02, SE=3.959, p=0.312, β=-0.44, SE=4.635,p=0,650).A significant relationship was observed between iCa levels and the QTc interval, which was longer in patients withhypocalcemia, but there was no significant relationship observed with TCa levels.