Some hospital bills can be written off if the medical care was done under charity care and you cannot afford to pay for the medical bills then they can usually be written off.
But some other medical bills cannot be written off and will be sent to collections if you cannot pay them which will harm your credit score.
The medical bills will stay on your credit report for up to 7 years before falling off your credit report.
Sometimes you may to file bankruptcy to eliminate the medical bills if you cannot afford to pay the medical bills.