In Ohio there is a three year look-back, though there was to be a vote in February at the State House making it a five year look back (though fortunately it wasn't reported to be retroactive). To apply for medicare to pay for a nursing home, any asset a person had must be exhausted. If she was co-owner of a home, she would have to sell her portion and it would go to medicare. Additionally, if she had an asset and were to die, Medicare could again use the three year (or possibly five year) look back and seize that asset.
We are currently going through this with my mother following a few strokes. We needed to sell her Condo, and basically liquidate her assets. We have banked enough money to get her through three years of nuring care in a nursing home. At the end of that three years, she had better be broke. Only at that time will we apply for medicare for her. The three year look back will show that all her assets from that point forward were used to pay for her care. With all assets then exhausted, Medicare will take over payment. The sad fact is, the three (or five) year lookbacks only hurt the people who actually planned ahead for their retirement. Those people who worked and saved are the ones who are penalized. If they had not bought a home, hadn't saved a dime and had instead blown it all on wine, women and song, they could apply for medicare immediately and wouldn't have to worry.
Edited to add: This is definitely one place you need a lawyer who knows your state's laws. Look for a lawyer/law firm who specializes in elder care. Ours charged around $2500 to handle everything. We sat down, went over everything, we brought in copies of all assets, did the math and they gave us our marching orders. We had it all wrapped up in two weeks. Granted, we were hurrying to beat the change in Ohio's laws, but we got it done.