Having a 30-day Preventable Readmission Rates should influence hospitals to make a thorough diagnosis and plan of treatment for their patients to insure that they remain healthy and do not readmit. That being said, if readmission needs to occur due to unseen factors, hopsitals should not be penalized. They are professionals, but they are not perfect either.
Medicare by design does not reduce such things. That is why Medicare for all is the solution to the various and horrible healthcare issues that plague Americans within the United States of America. It's so easy, we should be doing it instead of this Obamacare nonsense, that should be abolished.