Psychiatric Comorbidities in Neurologic Hospitalizations in Portugal: A Nationwide Retrospective Observational Study

Abstract

Introduction: Psychiatric comorbidities have a significant impact on patients' quality of life and often go undetected in neurologic practice. The aim of this study was to describe and characterize psychiatric comorbidities among patients hospitalized due to a neurologic disorder in mainland Portugal.

Methods: A retrospective observational study was performed by analyzing hospitalization with a primary diagnosis of neurologic disorder defined as categories 76, 77, 79 - 85, 95, 109 of the Clinical Classification Software for International Classification of Diseases, Ninth Revision, Clinical Modification, occurring between 2008 and 2015 in adult patients (≥ 18 years of age). Psychiatric comorbidities were determined as the presence of a secondary diagnosis belonging to the Clinical Classification Software categories 650 to 670.

Results: A total of 294 806 hospitalization episodes with a primary diagnosis of a neurologic disorder were recorded in adult patients between 2008 - 2015 in Portuguese public hospitals. Approximately 26.9% (n = 79 442) of the episodes had a recorded psychiatric comorbidity (22.1%; 32.2%, female versus male hospitalizations). Patients with registered psychiatric comorbidities were younger (66.2 ± 16.2 vs 68.6 ± 17.2 with no psychiatric comorbidities, p < 0.001), presented lower all-cause in-hospital mortality rates, and significantly longer mean hospital stays. 'Delirium, dementia, amnestic and other cognitive disorders' were recorded in 7.4% (n = 21 965) of the hospitalizations, followed by alcohol-related disorders in 6.5% (n = 19 302) and mood disorders in 6.1% (n = 18 079). Epilepsy/seizures were the neurologic disorders with the highest proportion of recorded psychiatric comorbidities (39.9%).

Conclusion: Psychiatric comorbidities were recorded in more than a quarter of the hospitalizations with a primary diagnosis of a Neurologic disorder. Psychiatric comorbidities varied among neurological disorders and were associated with different demographic and clinical features.

Keywords: Comorbidity; Hospitalization; Mental Disorders; Nervous System Diseases.