Lactic acidosis and the relationship with metformin usage: Case reports

Area of Science:

• Clinical Medicine
• Endocrinology
• Pharmacology

Background:

• Lactic acidosis (LA) is a serious complication, particularly in patients with type 2 diabetes mellitus (T2DM).
• Metformin is a common medication for T2DM, but its association with LA requires careful evaluation.
• Understanding risk factors for LA and in-hospital mortality is crucial for patient management.

Purpose of the Study:

• To retrospectively review LA cases in T2DM patients and assess the relationship with metformin use.
• To investigate patient profiles and clinical variables associated with in-hospital mortality in LA patients.
• To identify predictors of mortality in patients experiencing LA.

Main Methods:

• Retrospective review of LA patients (lactate >5.0 mmol/L, pH <7.35) admitted to Royal Hobart Hospital over 4 years.
• Data collection included demographics, medical history, medications, comorbidities, and pathology results.
• Multivariate logistic regression analysis was employed to determine predictors of in-hospital mortality.

Main Results:

• 139 LA patients were identified; 23 had T2DM, and 11 were on metformin.
• All metformin users had co-existing conditions predisposing them to LA.
• In-hospital mortality was high (51.8%), with older age and lower pH identified as independent predictors of death.

Conclusions:

• LA is associated with significant in-hospital mortality, with age and pH being key risk factors.
• In T2DM patients with LA, metformin use was consistently accompanied by other risk factors for LA.
• The contribution of metformin to LA in T2DM patients may be overestimated when other risk factors are present.