Maryland health officials are proposing to build a 280-bed regional acute-care hospital and expand outpatient care in Prince George’s County as they try to reshape the county’s health-care system and make it more financially secure.

During a news conference Wednesday in Cheverly, several officials offered more details of their vision to improve the county’s health by attracting more primary-care practices and more dentists, an effort launched a year ago.

Prince George’s has a high number of uninsured residents who rely on emergency rooms. Many of the insured residents seek health care outside the county.

“We are talking about a vision, not just a building, for a health-care system that really produces better health,” said Joshua Sharfstein, Maryland’s health secretary.

“We don’t want to just wait for people to have heart attacks and strokes and gunshot wounds. We want to provide a health-care system that prevents that.”

A high number of people who live in the predominantly African American county suffer from asthma, hypertension, HIV, cancer, diabetes and heart disease, studies show.

By early 2014, officials expect to make a formal application to the state for the new hospital, which would be aimed at serving the close-in Washington suburbs as well as Southern Maryland and is expected to open by 2017.

Before they fill out the forms, however, they are trying to assess community needs, gaps in coverage and how to attract people who can afford care but are spending their health-care dollars outside the county. They also are seeking political support for about $600 million in public funds.

The county, the state and the University of Maryland Medical System are expected to shoulder the costs, and the new network will be part of the university system.

A study by the University of Maryland School of Public Health shows that the county needs at least 61 more primary-care doctors (a 13 percent increase) as well as 31 additional dentists (a 7 percent increase) to meet recommended levels of care for a population of nearly 1 million.

The study also found that about 300,000 county residents live in what are in essence medical deserts and must travel miles, often by limited public transportation, to get to a hospital or medical practice.

Because the county has a high number of residents without health insurance, many do not seek care until their needs become urgent. That can drive up the cost of their care and is one of many reasons why Dimensions Healthcare System, which operates the county-owned Prince George’s Hospital Center, is in financial trouble and for several years has relied on an annual state and county subsidy of $30 million.

Last year, recognizing that the public subsidy had done little to improve the county’s health statistics, Prince George’s County Executive Rushern L. Baker III (D) and Maryland Lt. Gov. Anthony G. Brown (D) pushed for the new system.

It would be anchored by the regional medical center with 280 beds, slightly smaller than predicted.

The center would care for the most seriously ill patients who need sophisticated treatment for cancer, cardiac care and other specialities, officials said. For lesser illnesses and preventive care, patients could use ambulatory care centers in Beltsville, Bowie, Suitland, Upper Marlboro and Cheverly, replacing the hospital, said John W. Ashworth III, senior vice president for network development at the University of Maryland Medical System. It would be closely aligned with the county’s public health clinics as well.

“It is an awesome opportunity to build, from the ground up, the health-care system,” Sharfstein said.