Metformin is a drug frequently prescribed to patients with type 2 diabetes. Furthermore, diabetes can lead to micro- and macrovascular complications that may cause chronic organ failure. The presence of diabetes also increases the risk of infections. All of these factors contribute to the frequent admission of patients to the ICU who have been receiving metformin treatment in the preceding days. Acute renal failure, which is also frequently observed upon admission to the ICU, increases the risk of metformin overdose. In cases of overdose, metformin acts on several metabolic pathways that can lead to or even accelerate metabolic acidosis, sometimes severe. However, the impact on prognosis is controversial.

The role of metformin in lactic acidosis in patients treated for acute illness may be underestimated in routine practice.

This study aims to investigate the impact of prior metformin treatment on ICU survival in patients admitted to the ICU with severe lactic acidosis.

Inclusion Criteria:

• Adult patient (≥18 years)
• Admitted to the intensive care unit of Hautepierre Hospital - Strasbourg University Hospital between January 1, 2014, and December 31, 2023
• Having experienced lactic acidosis (pH <7.35 and lactate level ≥5 mmol/L) within the first 24 hours of hospitalization.

Exclusion Criteria:

• Patient without arterial blood gas measurements during the first 24 hours of admission
• whose background treatment is unknown and could not be determined
• for whom a limitation of active therapies was implemented before or during the first 24 hours of hospitalization

Adult patient (≥18 years) having experienced lactic acidosis (pH <7.35 and lactate level ≥5 mmol/L) within the first 24 hours of hospitalization.