[jdmcnugent]

They certainly do track it because Medicare will not pay for a second hospital stay in many cases.

https://www.cms.gov/Medicare/Quality-Initiatives-Patient-Ass...

Beware of unintended consequences though, hospitals are less inclined to permit riskier surgeries on unhealthy patients if they think the risk of readmissions is too high. Good luck getting your knee replacement if you are a 300lb diabetic smoker.