As few as six percent of Columbus residents could be without health insurance by 2016. Thatâs according to a new study by the Robert Wood Johnson Foundation and the Urban Institute. The report says the Affordable Care Act will help reduce the number of uninsured in Columbus by about two-thirds over the next two years, down to about 35,000 people. The study says about a quarter of those lacking coverage by then will be undocumented immigrants. The survey says cities in states that opted to expand Medicaid programs, like Columbus and Ohio, will see the most progress in insuring residents.