New to care: demands on a health system when homeless veterans are enrolled in a medical home model.

Objectives: We compared service use among homeless and nonhomeless veterans newly enrolled in a medical home model and identified patterns of use among homeless veterans associated with reductions in emergency department (ED) use.
Methods: We used case-control matching with a nested cohort analysis to measure 6-month health services use, new diagnoses, and care use patterns in veterans at the Providence, Rhode Island, Veterans Affairs Medical Center from 2008 to 2011.
Results: We followed 127 homeless and 106 nonhomeless veterans. Both groups had similar rates of chronic medical and mental health diagnoses; 25.4% of the homeless and 18.1% of the nonhomeless group reported active substance abuse. Homeless veterans used significantly more primary, mental health, substance abuse, and ED care during the first 6 months. Homeless veterans who accessed primary care at higher rates (relative risk ratio [RRR] = 1.46; 95% confidence interval [CI] = 1.11, 1.92) or who used specialty and primary care (RRR = 10.95; 95% CI = 1.58, 75.78) had reduced ED usage. Homeless veterans in transitional housing or doubled-up at baseline (RRR = 3.41; 95% CI = 1.24, 9.42) had similar reductions in ED usage.
Conclusions: Homeless adults had substantial health needs when presenting for care. High-intensity primary care and access to specialty care services could reduce ED use.