By the time people have accrued medical debt, the thing that was going to change their lives in relation to that debt - the procedure itself - has already occur

By the time people have accrued medical debt, the thing that was going to change their lives in relation to that debt - the procedure itself - has already occurred. And like others in here are saying, many are just willing to tell hospitals "You can't squeeze blood from a stone" in relation to paying off the debt, so paying it just removes some debt they didn't intend on paying anyways. Where the problem comes from is that people put off procedures that are necessary because they are afraid of the debt. Those people never get the debt that has to be paid off to begin with, so they wouldn't be a focus of the study. That being said, they're at the very least more miserable because they're not going to the doctor to get treated. They could also be less productive, develop more expensive conditions, or die.