Acute systemic diseases, such as severe
infections, can lead to
electrolyte and
acid-base alterations. To study the presence of
electrolyte imbalance in severe
COVID-19, we investigated the frequency and consequences of changes in
electrolyte and
acid-base patterns over time. We performed a retrospective cohort study including 406 patients with severe
COVID-19. Levels of
electrolytes, base excess, pH, serum osmolality, and hematocrit, the first 2 weeks of hospitalization, were collected daily from the laboratory database and clinical data from patients' medical records. We found that
hyponatremia was present in 57% of the patients at admission and 2% in
hypernatremia. However, within 2 weeks of hospitalization 42% of the patients developed
hypernatremia, more frequently in
critically ill patients. Lower levels of
sodium and
potassium during admission were associated with the need for
mechanical ventilation. Decreased pH at admission was associated with both death and the need for
mechanical ventilation.
Hypernatremia in the ICU was combined with rising base excess and a higher pH. In the group without
intensive care,
potassium levels were significantly lower in the patients with severe
hypernatremia. Presence of
hypernatremia during the first 2 weeks of hospitalization was associated with 3.942 (95% CI 2.269-6.851) times higher odds of death. In summary,
hypernatremia was common and associated with longer
hospital stay and a higher risk of death, suggesting that the dynamics of
sodium are an important
indicator of severity in
COVID-19.