Characteristics and prognostic factors of adult poisoning patients in the intensive care unit: A retrospective cohort study using the Japanese intensive care patient database

Poisoning presents significant challenges in intensive care, with presentations ranging from mild to life-threatening conditions. Understanding the characteristics and prognostic factors of poisoning patients is crucial for developing treatment strategies and optimizing resource allocation. This study examined the characteristics and outcomes of adult poisoning patients admitted to intensive care units and evaluated the applicability of the Acute Physiology and Chronic Health Evaluation III scoring system. We conducted a multicenter retrospective cohort study using the Japanese Intensive Care Patient Database from April 2015 to March 2023. Adult poisoning patients (aged ≥16 years) from 94 intensive care units were categorized into six groups: medications, psychotropic medications and substances of abuse, alcohols, domestic and industrial chemicals, toxic gases, and natural toxins and envenomations. Clinical characteristics, management, and outcomes were analyzed. Among 1930 patients (median age 45.0 years, 43.1% male), psychotropic medications constituted the largest category (58.5%). Intensive care unit and hospital mortality rates were 2.5% and 4.5%, respectively. Patients with chemical poisoning were significantly older (median 73.0 years) and required the highest mechanical ventilation rates (74.6%). Mechanical ventilation consistently prolonged intensive care unit stay across all categories. Acute Physiology and Chronic Health Evaluation III demonstrated good discriminative performance (area under the receiver operating characteristic curve 0.895) but systematically overestimated mortality risk (standardized mortality ratio 0.426, 95% confidence interval: 0.341-0.526). These findings highlight the limitations of applying general intensive care unit scoring systems to poisoning patients and emphasize the need for poisoning-specific prognostic tools.