Doctors call them frequent fliers: Patients who leave the hospital, only to boomerang back days or weeks later. They have become a challenge not only for hospitals and doctors but also for those trying to rein in rising healthcare costs. Typically elderly and suffering from the chronic diseases that account for 75% of healthcare spending, their experiences of being readmitted time and again reflect many of the deficiencies in a fragmented, poorly coordinated health system geared toward acute care, according to this article from the Washington Post.