Few understand that hospitals are paid by Medicare according to DRG coding. See link:
https://www.verywellhealth.com/how-does-a-drg-determine-how-much-a-hospital-gets-paid-1738874
So think--for instance: Mom goes in with pneumonia. She is 84 years old. She is allotted the same number of days as the 24-year-old with same diagnosis. However, Mom is unlikely to leave in the allotted time, whereas the 24-year-old may exit the next day.
This complicates services.
Say 3 days are allotted for "pneumonia" code. Mom stays 7, but the 24-year-old is out in 1 day. This means the hospital LOSES money on Mom and gains money on Junior.
This incentive is part of the reason hospitals send people home before they are ready.
This incentive is one of the reasons hospitals add on codes such as "arthritis flare", "dementia" and etc. to try to get more days added.
But one of the complications of our medical system.
I wish that billing was fair and honest, then we wouldn't have to have a system that games are played to get fair and honest payment.
So screwed up!