Trauma-related mortality of patients with severe psychiatric disorders: population-based study from the French national hospital database.

Background: Most research on mortality in people with severe psychiatric disorders has focused on natural causes of death. Little is known about trauma-related mortality, although bipolar disorder and schizophrenia have been associated with increased risk of self-administered injury and road accidents.

Aims: To determine if 30-day in-patient mortality from traumatic injury was increased in people with bipolar disorder and schizophrenia compared with those without psychiatric disorders.

Method: A French national 2016 database of 144 058 hospital admissions for trauma was explored. Patients with bipolar disorder and schizophrenia were selected and matched with mentally healthy controls in a 1:3 ratio according to age, gender, social deprivation and region of residence. We collected the following data: sociodemographic characteristics, comorbidities, trauma severity characteristics and trauma circumstances. Study outcome was 30-day in-patient mortality.

Results: The study included 1059 people with bipolar disorder, 1575 people with schizophrenia and their respective controls (n = 3177 and n = 4725). The 30-day mortality was 5.7% in bipolar disorder, 5.1% in schizophrenia and 3.3 and 3.8% in the controls, respectively. Only bipolar disorder was associated with increased mortality in univariate analyses. This association remained significant after adjustment for sociodemographic characteristics and comorbidities but not after adjustment for trauma severity. Self-administered injuries were associated with increased mortality independent of the presence of a psychiatric diagnosis.

Conclusions: Patients with bipolar disorder are at higher risk of 30-day mortality, probably through increased trauma severity. A self-administered injury is predictive of a poor survival prognosis regardless of psychiatric diagnosis.