Hypocalcemia: a pervasive metabolic abnormality in the critically ill

Area of Science:

• Critical Care Medicine
• Endocrinology
• Clinical Chemistry

Background:

• Hypocalcemia is frequently observed in critically ill patients, often linked to sepsis.
• The prevalence and severity of hypocalcemia in non-septic critically ill patients require further definition.

Purpose of the Study:

• To determine and compare the incidence and severity of hypocalcemia across different patient groups, including critically ill patients in various intensive care units (ICUs).
• To compare hypocalcemia rates in critically ill patients versus non-critically ill ICU patients and hospitalized non-ICU patients.

Main Methods:

• A comparative study involving three groups: critically ill ICU patients (Group A, n=99), non-critically ill ICU patients (Group B, n=50), and hospitalized non-ICU patients (Group C, n=50).
• Measurement of ionized calcium (Ca) levels to identify hypocalcemia (defined as Ca < 1.16 mmol/L).
• Correlation analysis with severity scores (APACHE II), mortality, hypomagnesemia, blood transfusions, acute renal failure, and QT interval.

Main Results:

• Hypocalcemia incidence was significantly higher in critically ill ICU patients (88%) compared to non-critically ill ICU patients (66%) and non-ICU patients (26%) (P < 0.001).
• In critically ill patients, hypocalcemia frequency was not dependent on ICU setting or sepsis but correlated with illness severity (APACHE II score) and mortality.
• Hypomagnesemia, blood transfusions, and acute renal failure were associated with lower calcium levels.

Conclusions:

• Hypocalcemia is extremely prevalent in hospitalized patients, particularly the critically ill, irrespective of sepsis.
• The severity of illness is a key factor associated with hypocalcemia, which also correlates with increased mortality risk.
• The study highlights the frequent need for intravenous calcium therapy due to hypocalcemia, underscoring the clinical significance of this electrolyte imbalance.