Influence of psychiatric comorbidity on in-hospital costs for multitrauma patients

Introduction: The purpose of this study was to quantify the impact of psychiatric comorbidity on in-hospital costs after multitrauma. Methods: A retrospective single-center cohort study identified adult trauma patients with an Injury Severity Score (ISS) ≥ 16, who entered the hospital between January 2018 and December 2019. Descriptive statistics were assessed for patient characteristics, injury characteristics, and injury outcomes. Bivariate analysis was performed for in-hospital costs between patients with and without psychiatric comorbidity. The psychiatric cohort was then further divided into different sub-cohorts by status of their psychiatric comorbidity: ‘Acute’ for patients with no known history of psychiatric illness who required inpatient psychiatric consultation for a newly diagnosed or suspected psychiatric illness, ‘Stable’ for patients with a prior psychiatric history that did not require inpatient psychiatric consultation, and ‘Chronic’ for patients with a prior psychiatric history that required continued inpatient psychiatric consultation. Baseline demographic and in-hospital cost data was compared between these cohorts. Results: Of the 616 patients meeting inclusion criteria, 94 patients (15.3%) either suffered from pre-existing psychiatric illness, needed psychiatric consultation during hospitalization, or suffered both pre-existent from a psychiatric illness and needed psychiatric consultation during hospitalization. The psychiatric cohort generated significantly higher total in-hospital costs than the control cohort (median costs: €22.000 versus €15.200, respectively (p < 0.01). In particular, the Acute psychiatric cohort generated the highest hospital expenses (median total in-hospital costs €47.000). Multivariable regression analyses did not reveal psychiatric comorbidity as an independent predictor of higher in-hospital costs (p = 0.88). Instead, the duration of hospital stay (p < 0.01), ISS (p < 0.01), and the number of total surgical interventions (p < 0.01) independently predicted higher total in-hospital costs. Conclusions: Although in-hospital costs of multitrauma patients were higher among patients with psychiatric comorbidity, psychiatric comorbidity does not independently predict increased in-hospital costs for patients after multitrauma. Instead, higher in-hospital costs are due to longer inpatient stay, higher ISS and greater number of surgical interventions among those with psychiatric comorbidity.