Prognostic value of blood lactate levels in predicting cardiac adverse events in patients presenting with drug intoxication

Background Acute drug intoxication (ADI) is a major cause of morbidity and mortality, often leading to complications such as cardiac adverse events (CAEs). Lactate levels are widely used to indicate anaerobic metabolism and hypoperfusion, with known prognostic values in various clinical settings. Objectives This study aimed to assess the prognostic value of serum lactate levels and lactate clearance (LC) in predicting CAEs in patients presenting to the emergency department (ED) with suicide‐related ADI. Methods This retrospective study analyzed records of 140 patients admitted to the ED with suicide‐related ADI. Demographic, clinical, and laboratory data were collected. CAEs were defined using specific criteria. Lactate levels were measured at 0 and 6 h, and LC was calculated. Results The median age of the patients was 31.0 [23.0; 43.0] years, with 37.1% male and 62.9% female. CAEs occurred in 29.3% of the patients. The ingestion of salicylates, nonbenzodiazepine‐hypnotics, angiotensin‐converting enzyme inhibitors, and beta‐blocker/calcium channel blockers significantly increased the risk of CAE ( p < 0.05). All patients who ingested tricyclic antidepressants experienced CAEs ( p < 0.001). 0‐h lactate (OR: 10.11, 95% CI: 4.25–37.07) and LC (OR: 0.88, 95% CI: 0.82–0.93) were identified as strong prognostic factors for CAE risk. The optimal cutoff for predicting CAEs was determined as ≥3.3 mmol/L for 0‐h lactate (AUC: 0.921) and ≥2.7 mmol/L for 6‐h lactate (AUC: 0.984). LC (AUC: 0.799) demonstrated moderate performance in predicting CAEs, with an optimal cutoff of ≤35.3%. Conclusions Lactate levels and LC are useful prognostic markers for predicting CAEs in ADI, aiding early risk stratification in the emergency setting.