The growing number of hospital-based physicians in the U.S. could be taxing Medicare resources, government-funded researchers suggest in a new report. They found hospitalized Medicare patients checked out sooner when they were cared for by a hospital doctor than when their primary care physician followed them. Yet they were also more likely to bounce back into the hospital over the next month. As a consequence, the savings from the shorter original stay were offset by a higher bill for health services later -- potentially adding up to an extra $1.1 billion across all Medicare patients. Hospital-based doctors, also called hospitalists, have become increasingly common in recent decades, and now tally some 30,000 in the U.S., according to the Society of Hospital Medicine. The idea behind the movement is to streamline and improve patient care, and earlier research has shown that the approach does indeed lead to shorter hospital stays.