Newswise — Vanderbilt researchers have been selected to receive a national grant as part of a push to gauge the coming impact of the Affordable Care Act (ACA). The Vanderbilt University Medical Center team is producing a tool that will predict and map hot spots where shortages for primary care providers are likely to occur as millions of Americans become insured in 2014. John Graves, Ph.D., assistant professor of Preventive Medicine and affiliate of the Institute of Medicine and Public Health, is principal investigator of the yearlong project, funded by the State Health Access Reform Evaluation (SHARE) program of the Robert Wood Johnson Foundation. SHARE seeks to fill gaps in research related to state-level implementation of the ACA. There is widespread concern about future access to primary care as Americans become insured through state-based insurance exchanges or an expansion of Medicaid projected to rival the number of people initially covered by Medicare in 1965. “We know 32 million people will become insured, but nailing down where these people will come from has been difficult. The interesting aspect of our work is it will map out where the coverage expansions will happen in local markets, and will highlight provider shortage areas in a visual way,” Graves said. VUMC co-investigators on the project are Robert Dittus, M.D., MPH, associate vice chancellor for Public Health and Health Care, and Peter Buerhaus, Ph.D., R.N., director of the Center for Interdisciplinary Health Work force Studies. Graves said the technique of scaling down the effect of a national policy to local regions is called small-area microsimulation modeling. The Vanderbilt model will be the first that can be used to estimate the local impact of the ACA within any state. The Vanderbilt model uses a combination of data including federal surveys and state administrative data to predict the location of people who will become insured in 2014. The methodology then links data on coverage with current information about the medical work force, including hospitals, doctors and nurses in each locality. Geospatial software is used to create a colorful map that displays a “topographic” scale of need for providers. An initial test of the microsimulation was performed for Ohio, where deeper colors show provider shortage areas running in river-like strips between large islands of provider-rich urban areas. “For example, in the city of Columbus we found each provider might expect to see just five newly insured patients despite predicted large numbers of newly insured patients. But just a few miles outside the city, despite predicted small numbers of newly insured, there are so few providers that each could expect up to 200 patients,” Graves said. The project draws heavily on Buerhaus’ knowledge of the health care work force and its dynamics. “In this research, we hope to pinpoint areas where demand is likely to expand the greatest, and determine whether the capacity of the current health care work force is likely to match the increase in demand. Results should help policy makers anticipate where there may be shortfalls in work force capacity and the magnitude of consequent decreases in access to health care,” Buerhaus said. Dittus’ work to test novel approaches for providing primary care will offer a glimpse of possible solutions for areas in the greatest need. “Since the Supreme Court’s reaffirmation of the constitutionality of the ACA legislation, there has been intense activity across the country to assess the impact of portions of the law coming into effect,” Dittus said. “This project is precisely what Vanderbilt’s developing public policy research team has the skills and experience to do: produce high quality analysis of the effects of national health policy to allow leaders in health care and legislators access to critical information to implement positive change.” Harvard Medical School statistician Alan Zaslavsky, Ph.D., will provide consultation for the team. Because more people will be insured, the federal government plans to cut Disproportionate Share Hospital (DSH) funding for individual hospitals — including Vanderbilt — by at least 25 percent and as much as 50 percent, beginning in 2014. The Vanderbilt microsimulation model will also allow hospitals to predict the impact of these cuts.