More patients are being confronted with hospital "facility fees" for routine doctors' office visits. The costly trend has caught the attention of the Medicare Payment Advisory Commission. Facility fees for simple office visits, it estimated, will add $2 billion a year to Medicare spending by 2020. For a middle-range doctor's office visit, such fees increase the total charge by more than 80 percent. Hospitals say the fees are needed to defray overhead such as equipment, staff, medical-records systems, diagnostic imaging and care not covered by insurance or underpaid by Medicare or Medicaid.