Utilization of primary care by veterans with psychiatric illness in the National Department of Veterans Affairs Health Care System.

BACKGROUND: Psychiatric illness is associated with increased medical morbidity and mortality. Studies of primary care utilization by patients with psychiatric disorders have been limited by nonrepresentative samples and confounding by medical co-morbidity.
OBJECTIVE: To determine whether patients with psychiatric disorders use primary care services differently than patients without these disorders, after controlling for medical co-morbidity.
DESIGN: Data from the 1999 Large Health Survey of Veterans (LHS) (n = 559,985) were linked to VA administrative data in order to identify veterans who received primary care. After adjusting for sociodemographic and clinical characteristics, medical co-morbidity, and facility characteristics, multivariate logistic regression was used to evaluate whether seven psychiatric diagnoses were associated with an increased or decreased likelihood of any primary care visit over 12 months.
RESULTS: Veterans with either schizophrenia, bipolar disorder or a drug use disorder were less likely to have had any primary care visit during the study period: [OR 0.61, 95% CI 0.59 to 0.63], [OR 0.63, 95% CI 0.60 to 0.67] and [OR 0.88, 95% CI 0.83 to 0.92], respectively, than veterans without these diagnoses, even after controlling for medical co-morbidity. Among patients with any primary care utilization, those with six of the seven psychiatric diagnoses had fewer visits in the study period.
CONCLUSIONS: Patients with schizophrenia, bipolar disorder or drug use disorders use less primary care than patients without these disorders. Interventions are needed to increase engagement in primary care by these vulnerable groups.