Last week, Gallup released a report analyzing 43 U.S. Metropolitan areas and found that more than one in five Americans are uninsured. The study looked at the top 10 areas with the highest percentage rate of uninsured individuals, not surprisingly, located in highly populated states: California, Florida, Texas, Nevada, and Washington. The survey was among 190 metro areas.

Under the ACA, the uninsured residents of California, Nevada, and Washington will become eligible for Medicaid due to the individual state’s decisions to participate in the expansion. This could provide significant amount of health coverage to low-income, uninsured residents because the expansion issues a mandatory Medicaid eligibility to all individuals under the age of 65 with income levels up to the effective minimum threshold of 138% of federal poverty level (FPL).

This may be good news to some states and bad news for those who have decided not to participate in the expansion. For example, California estimates that there are currently 851,000 uninsured children and adults; however, those uninsured individuals will soon become eligible for Medicaid coverage in 2014 due to the state’s decision to expand Medicaid (Figure 1).

In contrast, Texas is ranked in the top 10 states with the highest uninsured populations but has no intentions to participate in the expansion.

Under the ACA, every legal resident of the United States is required to obtain health insurance or to pay a penalty tax. Alarmingly enough, in the metro area of McAllen-Edinburg-Mission in TX, 48.8% of residents are uninsured. However, TX chose not to expand Medicaid under the ACA. The uninsured TX residents will soon have to face a mandatory penalty tax or enroll in Medicaid, CHIP, or private coverage plans through the exchange.

In my opinion, some states could benefit from the Medicaid expansion while it may become a financial burden to other states. Ultimately, it is up to the individual states to decide for themselves. However, I hope that the state leaders are mindful of their residents when making an important decision such as expanding or opting Medicaid expansion.