A contract dispute between one of California's largest health insurers and UCLA could force thousands of patients at the university's medical centers to seek treatment elsewhere if the disagreement is not resolved by the end of December. Blue Shield says the rates for care at at Ronald Reagan UCLA Medical Center in Westwood and nearby Santa Monica-UCLA Medical Center and Orthopaedic Hospital have nearly doubled in the last five years, and the costs for inpatient treatments are already 41% higher than what it pays on average in Southern California hospitals overall.