The constitution forbids congress and the states from enforcing laws on an ex-post facto basis. Normally, this is not a problem although the Clinton administration did face legal challenges when it tried to raise taxes on a retroactive basis. Ex-post facto laws and retroactive taxes have nothing to do with Medicare is retroactive or not.
A person on Medicare can get enrolled in the program retroactively. This usually happens with a disability claim or it occurs because an oversight. When an individual finds out that his Medicare is retroactive, he receives a letter in the mail and new insurance cards. The letter provides the documentation for when the coverage would have become effective. The insurance cards carry that date on the letter. If a check comes in the envelope with the insurance cards, it means that the person also is eligible for social security retirement or social security disability benefits.
If a person gets a retroactive Medicare card, the first thing he should do is file insurance claims for medical care the he might need. As long as these claims do not exceed the time limit for such claims, the individual should receive some reimbursement for these expenses. Medicare is retroactive only in certain circumstances. In most cases, a retroactive decision comes about because a disability claim successfully went through. A person who receives such a letter and the cards can find more detailed information about how it works on Medicare’s official website.
A retroactive enrollment in Medicare Part A or Part B does not necessarily give the person prescription drug coverage. The letter that explains the enrollment decision also tells the person who receives the letter how long he has to enroll in a prescription drug plan. The drug plan can also be made to go back to the date of the original Medicare enrollment.