Underlying claims costs -- which form the basis for insurers' health care coverage premiums -- will jump by one-third across the U.S. after the Affordable Care Act goes into effect next year, according to the Society of Actuaries.

But that increase won't be felt evenly across the country because the study forecasts that some states will feel more pain than others. Among the hardest-hit will be Ohio, where claims costs will jump by almost 81%, and California, with a 62% increase.

Other states projected to see big increases in claims costs are Wisconsin, with an 80% jump; Indiana at 68%; Maryland, with a 67% bump; and Idaho at 62%.

[...] The silver lining in the study is its finding that some states will actually see decreasing costs. Among those are New York, with claims costs sliding 14%, and Massachusetts, with a 13% decline.