Hypocalcemia with Immune Checkpoint Inhibitors: The Disparity among Various Reports

Area of Science:

• Oncology
• Endocrinology
• Immunology

Background:

• Immune checkpoint inhibitors (ICPIs) can cause immune-related adverse events.
• Hypocalcemia is a potential adverse event, but its true incidence with ICPIs is unclear.
• Previous trials reported high hypocalcemia rates without clarifying etiology.

Purpose of the Study:

• To determine the true incidence of hypocalcemia in patients receiving ICPIs.
• To investigate the role of albumin-corrected calcium levels in assessing hypocalcemia.
• To compare hypocalcemia rates with and without confounding factors.

Main Methods:

• Retrospective chart review of patients receiving ICPIs from 2015-2018.
• Patients divided into two groups: those with and without calcium-altering conditions/medications.
• Albumin-corrected calcium levels used to calculate true hypocalcemia incidence.

Main Results:

• Uncorrected hypocalcemia incidence was 8.4% in Group 1 and 19.3% in Group 2.
• After albumin correction, true hypocalcemia incidence was 0.56%.
• Higher uncorrected rates were observed in patients with calcium-altering factors.

Conclusions:

• The true incidence of hypocalcemia in ICPI patients is very low when using albumin-corrected values.
• High reported hypocalcemia rates in prior studies may be attributed to uncorrected serum calcium measurements.
• ICPIs are unlikely to be a significant cause of true hypocalcemia.