Hospitalization for carbon monoxide poisoning is associated with substance use and mood disorders

Carbon monoxide (CO) poisoning continues to result in hospitalization and mortality. We sought to analyze risk factors associated with inpatient admission for CO poisoning. Retrospective study of the US National Inpatient Sample (NIS) database. All adults with ICD-10 code for CO poisoning from 01/01/2016 to 12/31/2020 were identified. Demographics, co-morbid conditions, insurance type, household income, length of stay (LOS), total charges, and mortality were abstracted. Univariable logistic regression was used to calculate unadjusted odds ratios (ORs) for CO poisoning admissions. Variables with p-value ≤ 0.2 were included in a multivariable logistic regression model. Of 148,767,786 total hospitalizations, 14,625 had a principal diagnosis of CO poisoning. Compared to non-CO hospitalizations, the CO group was younger (median age 54 vs 61 years; p < 0.001), included more males (61.1 vs 42.7%; p < 0.001), and higher in-hospital mortality (4.0 vs 2.4%; p < 0.001). Although LOS was similar (3 vs 3; p = NS), the CO group had lower median hospital charges ($24,368 vs $ 32,667; p < 0.001). In multivariable analysis, male sex (OR 1.98; 95% CI 1.83-2.15), alcohol use disorder (OR 1.89; 95% CI 1.71-2.10), cannabis use disorder (OR 1.26; 95% CI 1.09-1.47), mood disorders (OR 2.65; 95% CI 2.44-2.88), and suicide ideation (OR 1.74; 95% CI 1.50-2.02) were independently associated with hospitalization. In this 5-year analysis, cannabis use, mood disorders, and suicidality were significant risk factors for CO-related hospitalization in addition to previously known risks of alcohol use and male gender. Since mood and substance use disorders are increasing globally, these modifiable risk factors deserve priority attention from clinicians and policymakers.