Medical-Surgical Hospitalization Among Veterans With Psychiatric and Substance Use Disorders.

BACKGROUND

Mental illness is associated with an increased risk for medical hospitalizations.

OBJECTIVE

This study investigates the degree to which nonpsychiatric factors account for these hospitalizations.

METHODS

Using National Veterans Health Administration (VHA) fiscal year 2012 data for 2 million veterans under the age of 60 years, hospitalization risks were compared for veterans with and without mental illnesses. Bivariate analyses identified factors associated with mental illnesses. Multiple logistic regression was used to calculate adjusted psychiatric risk for medical hospitalization, controlling for these factors.

RESULTS

Veterans carrying mental health diagnoses were at increased risk for hospitalizations (odds ratio [OR] = 2.52, 2.48-2.55). Among individual diagnoses, alcohol use disorder (AUD) (OR = 3.84, 3.78-3.91) and drug use disorders (OR = 4.58, 4.50-4.66) were associated with the highest risk. After adjusting for nonpsychiatric medical, addiction-related, and care utilization factors and the use of outpatient medical services, veterans with mental illnesses were at increased risk for medical hospitalization (OR = 1.43, 1.41-1.45). After further adjustment for AUD and drug use, hospitalization risk decreased further (OR = 1.23, 1.21-1.26) while the association of AUD and hospitalizations remained high (OR = 1.77, 1.73-1.81).

CONCLUSIONS

Medical comorbidities and service use accounted for most, but not all, of the increased risk of medical hospitalizations associated with mental illness. Even after accounting for poor health, AUD remained strongly associated with medical hospitalization.