Maine is at the forefront in trying to improve health care for the patients who make multiple trips to the hospital an d drive up costs for everyone else, a national health care expert said Tuesday. Jeffrey Brenner, director of the Institute of Urban Health at Cooper Hospital in Camden, N.J., spoke to dozens of Maine health care providers during a meeting at Maine General's Harold Alfond Center for Cancer Care. "Maine is on the cutting edge of trying to figure this out," he said. "There's a real sense of collaboration and teamwork in Maine."