Vitamin D in the critically ill - update 2024.

Purpose of review: This review aims to summarize the latest publications on vitamin D focused on critically ill patients.

Recent findings: Vitamin D deficiency is common in critically ill patients (children and adults) and associated with a higher risk for mortality and morbidity as well as sepsis, acute respiratory failure, acute renal failure and prolonged ICU stay. As it is an inexpensive substance with a wide safety margin, acute treatment in form of a loading dose in addition to ongoing maintenance therapy is an interesting option in the ICU. The potential benefit of acute native (biologically inactive) vitamin D treatment has not fully been answered but even a small survival benefit demonstrable in very large analyses could be relevant to critical care. To date, less than 5000 patients cumulative have been enrolled in randomized controlled trials concerning vitamin D, with substantial heterogeneity in trial design regarding population (with or without deficiency, coronavirus disease 2019, different age groups, underlying illnesses), metabolite, dosing, outcome, and more.

Summary: More research is needed, but vitamin D supplementation represents a simple intervention with an excellent safety profile. As adequate vitamin D is essential to the health of multiple organ systems, rapid normalization of deficiency states could translate to benefits across the wide range of diagnoses and organ dysfunctions experienced in the ICU setting. As a minimum, we recommend administering the standard daily dose of vitamin D3 in the critically ill patient.