The total economic output of hospitals and related services in Los Angeles and five surrounding counties is $85.5 billion, or 12.1 percent of the region’s $708 billion economy, according to a report released Tuesday.

The Los Angeles County Economic Development Corp. study, based on statistics from 2004, also points out that more than half of the hospitals in the six-county region lost money on patient care.

The study, “Hidden in Plain Sight: The Economic Contribution of Southern California Hospitals and Related Services,” measured the economic impact that 212 hospitals in Southern California have on the economy. The study found that 107 of those facilities spent more treating patients than they were able to collect from insurers or the patients themselves.

“Health care providers are caught in the middle of conflicting trends,” the study said. “On one hand, demand for their products is growing. On the other, rates for their services are under continuous downward pressure from buyers who acting on behalf of their private and public sponsors and members negotiate the lowest prices possible.”

The Hospital Association of Southern California commissioned the report covering the counties Los Angeles, Santa Barbara, Orange, Riverside, San Bernardino and Ventura.

The study noted that Los Angeles County had the largest hospital-related economic engine in the region, with $47.2 billion in economic output from the 116 hospitals that participated in the study. Hospitals and related services provided 352,000 full-time jobs paying $15.6 billion in wages. More than $1.1 billion in state, county and city tax revenues was generated in 2004, according to the study.

The study estimates that hospitals in the region would spend at least $8.2 billion on construction projects between 2005 and 2009, primarily on modernization and earthquake retrofitting.