California public employees will pay more for doctor visits and prescription drugs in order to hold health care premium increases to 6%, rather than the 15% to 18% hike that had been projected for next year based on HMO bids. The decision by the nation’s largest public pension fund marks a shift toward employees picking up a larger percentage of their health care costs and serves as an ominous warning for all employers. A number of factors are driving up health care rates, including an aging population, demand for prescription drugs, payment increases demanded by doctors and hospitals, looser cost controls, and laws requiring insurers to offer certain services.