Medicare could find itself in crisis unless lawmakers overhaul the program's physician payment formula, a congressional adviser warned Thursday. Glenn Hackbarth, who leads the Medicare Payment Advisory Commission (MedPAC), told a House panel that replacing the much-derided sustainable growth rate (SGR) is essential to ensuring seniors' access to care. "I'm not predicting a national crisis at this point," he said, "but we certainly can't rule it out, either." Hackbarth appeared before the House Energy and Commerce health subcommittee, which kicked off its legislative session with a hearing on Medicare payments to doctors.