Sen. Joseph R. Biden Jr., D-Del., plagued with health problems since February, was released from the hospital Saturday about three weeks after he underwent surgery to repair an artery near his brain. "I am happier than you can possibly believe to be out of the hospital," Biden said at a news conference outside Walter Reed Army Medical Center in Washington. "I am in good shape and anxious to go back to work." He also said that though his health problem didn't come to light until after he dropped out of the race for the Democratic presidential nomination, ending his campaign may have saved his life. "I think getting out of the race was, quite frankly, a godsend," he said. If he had stayed in the race, "the percentages are I might not have made it down here," he said. The 45-year-old senator withdrew from the race after acknowledging he plagiarized a law school exam.