My lede:

Nearly 20% of Medicare patients discharged from hospitals were readmitted within 30 days, costing taxpayers $17.4 billion, according to an April 2 study in the New England Journal of Medicine.

About 10% of rehospitalizations were planned to continue needed care, the study found. But as many as 40% of them — or about 1 million readmissions — were preventable, said Stephen F. Jencks, MD, MPH, lead author of the study (content.nejm.org/cgi/content/abstract/360/14/1418/).

The whole shebang.