WASHINGTON (AP) — President Barack Obama's health care law would let several million middle-class people get nearly free insurance meant for the poor, a twist government number crunchers say they discovered only after the complex bill was signed.

The change would affect early retirees: A married couple could have an annual income of about $64,000 and still get Medicaid, said officials who make long-range cost estimates for the Health and Human Services department.

Up to 3 million people could qualify for Medicaid in 2014 as a result of the anomaly. That's because, in a major change from today, most of their Social Security benefits would no longer be counted as income for determining eligibility.