Magnesium is an essential electrolyte involved in numerous physiological processes, including maintaining cellular integrity, regulating muscle tone, supporting cardiovascular function, and modulating immune responses. Despite its critical role, magnesium is often overlooked in clinical practice, earning it the title of the "forgotten electrolyte." Hypomagnesemia, defined as serum magnesium levels below 1.5 mEq/L, has been associated with adverse clinical outcomes such as increased mortality, prolonged ICU stays, and higher requirements for mechanical ventilation. Critically ill patients are particularly vulnerable to hypomagnesemia due to various underlying conditions, gastrointestinal losses, and renal complications. However, limited data are available from Bangladesh on the burden and clinical impact of hypomagnesemia in ICU settings. This study aims to assess the correlation between hypomagnesemia and clinical outcomes, including length of ICU stay, need for mechanical ventilation, and mortality among critically ill patients in a tertiary care ICU in Bangladesh.

Inclusion Criteria:

• Patients aged 18 years and above.
• Patients admitted to the Intensive Care Unit (ICU).
• Patients who have serum magnesium levels measured within 24 hours of ICU admission.

Exclusion Criteria:

• Patients with known end-stage renal disease on dialysis.
• Patients with a history of magnesium supplementation prior to ICU admission.
• Pregnant women.
• Patients with incomplete medical records or unavailable laboratory data.

Population will consist of critically ill adult patients admitted to the Intensive Care Unit (ICU) of a tertiary care hospital in Bangladesh. The study will include both male and female patients aged 18 years and above, irrespective of their underlying diagnosis, provided they meet the inclusion criteria. Patients will be assessed for serum magnesium levels (Hypo; Normo and Hyper) within 24 hours of ICU admission, along with relevant biochemical, hematological and clinical parameters. The study will exclude individuals with known end-stage renal disease on dialysis, those receiving magnesium supplementation prior to ICU admission, pregnant women and patients with incomplete medical records.

Individual Participant Data (IPD) will not be shared with other researchers to ensure the protection of patient confidentiality and comply with institutional and ethical guidelines. Only aggregated, de-identified data may be shared upon reasonable request and with appropriate ethical approvals.