Visits to primary care delivery sites: United States, 2008.

This study describes primary care delivery across ambulatory care settings. Although the majority of visits to primary care settings occur in physician offices (84%), OPDs and CHCs are important sources of primary care for poor and uninsured populations. CHCs also had a higher percentage of visits by patients with one or more chronic conditions compared with office-based physicians and OPDs. This higher burden may not be surprising, as there are well-established associations between socioeconomic status and health. Although OPDs and CHCs serve patients from similar neighborhoods and with similar sources of payment, OPDs receive fewer visits by patients with chronic disease. These observations may reflect true differences in case mix or differences in awareness or documentation of chronic disease across settings. The higher percentage of hospital OPD visits in which imaging and nonmedication treatment was ordered or provided compared with physician offices and CHCs may be due to greater access to these services in a hospital setting. Additionally, our analysis suggests OPDs serve a critical complementary function to CHCs by providing care for acute conditions. These findings are consistent with the role of CHCs and OPDs in the health care safety net. All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as to source, however, is appreciated.