A comorbid anxiety disorder does not result in an excess risk of death among patients with a depressive disorder

Abstract

Background: Several studies have demonstrated increased mortality associated with depression and with anxiety. Mortality due to comorbidity of two mental disorders may be even more increased. Therefore, we investigated the mortality among patients with depression, with anxiety and with both diagnoses.

Methods: By linking the longitudinal Psychiatric Case Register Middle-Netherlands, which contains all patients of psychiatric services in the Utrecht region, to the death register of Statistics Netherlands, hazard ratio's of death were estimated overall and for different categories of death causes separately.

Results: We found an increased risk of death among patients with an anxiety disorder (N=6919): HR=1.45 (95%CI: 1.25-1.69), and among patients with a depression (N=14,778): HR=1.83, (95%CI: 1.72-1.95), compared to controls (N=103,824). The hazard ratios among both disorders combined (N=4260) were similar to those with only a depression: HR=1.91, (95% CI: 1.64-2.23). Among patients with a depression, mortality across all important disease-related categories of death causes (neoplasms, cardiovascular, respiratory, and other diseases) and due to suicide was increased, without an excess mortality in case of comorbid anxiety.

Limitations: The presented data are restricted to broad categories of patients in specialist services. No data on behavioral or intermediate factors were available.

Conclusions: Although anxiety is associated with an increased risk of death, the presence of anxiety as comorbid disorder does not give an additional increase in the risk of death among patients with a depressive disorder. The increased mortality among patients with depression is not restricted to suicide and cardiovascular diseases, but associated with a broad range of death causes.