I am a just retired (at age 80) physician who completed 28 years of volunteering in free clinics staffed by volunteers and providing comprehensive care to the working poor who were not Medicaid eligible.

When the Patient Protection and Affordable Care Act (ACA) was passed, I was quite optimistic that the community efforts to care for the uninsured would be considerably enhanced by the new law. Some of the free clinics actually closed or reduced services in that anticipation.

I now realize that there will be serious shortcomings in some of the states, including South Carolina. The ACA was designed to increase access to health insurance by requiring states to expand Medicaid eligibility to people with incomes less than 138 percent of the Federal Poverty Level (FPL, which was $19,530 for a family of three in 2013), with the cost of expanded eligibility mostly paid by the federal government.

Recent studies suggest that Medicaid expansion will result in health and financial gains. Older studies also found salutary health effects of expanded or improved insurance coverage, particularly for lower income adults.

These studies also document an increase in utilization of most health care services.

The Supreme Court ruled in June 2012 that states may opt out of Medicaid expansion, and as of late last month, 24 states had done so.

These opt-out decisions will leave millions uninsured who would have otherwise been covered by Medicaid, but the health and financial impacts have not been quantified.

South Carolina's decision to opt out of Medicaid expansion may have adverse health and financial consequences. It is predicted that many low-income women will forego recommended breast and cervical cancer screening; diabetics will forego medications, and all low-income adults will face a greater likelihood of depression, catastrophic medical expenses and death. Disparities in access to care based on state of residence will increase.

Because the federal government will pay 100 percent of increased costs associated with Medicaid expansion for the first three years (and 90 percent thereafter), opt-out states are also turning down billions of dollars of potential revenue, which might strengthen their local economy.

The ACA's tax subsidy for insurance purchase on the exchanges is only available to persons with incomes above 100 percent of the FPL. People below this threshold in opt-out states (the so-called low-income "coverage gap") will see no benefit as the law goes into effect.

They may even see harm because the ACA cuts disproportionate share funding to safety net hospitals, reducing the resources available to care for the remaining uninsured.

Despite the widely held belief that almost all Americans will be insured under the ACA, more than 32 million people will remain uninsured after the law goes into effect.

Some 500,000 of our state's residents will remain uninsured and will be at a significant disadvantage, and may forego gains in access to care, financial well-being, physical and mental health, and longevity that would be expected with expanded Medicaid coverage.

Frederic G. Jones, M.D.

Long Grove Drive

Mount Pleasant

Dr. Jones is a board certified cardiologist who served 28 years as an Air Force physician, followed by a 20 year career as chief medical officer of the Anderson Area Medical Center.