As policymakers try to revive emergency medical care at the recently shuttered North Adams Regional Hospital, another Massachusetts hospital network recently had its rating outlook lowered to stable from positive, with analysts saying Steward Health Care System needs to continue restructuring.

In its April 10 rating outlook change, Moody’s Investors Service wrote, “Moody’s anticipates that the company will have to continue to undergo significant restructuring efforts in order to improve margins and contend with weak volume trends and a very competitive market . . . The rating reflects the benefit of the significant presence Steward has in its eastern Massachusetts market but also the risk of having all of its operations in one state.”

Steward, a for-profit health network, has more than 17,000 employees serving more than one million patients in 150 Bay State communities.

Hospitals in its system include Carney Hospital in Dorchester, Good Samaritan Medical Center in Brockton, Holy Family Hospital in Methuen, Merrimack Valley Hospital in Haverhill, Morton Hospital in Taunton, Nashoba Valley Medical Center in Ayer, New England Sinai Hospital in Stoughton, Norwood Hospital, Quincy Medical Center, Saint Anne’s Hospital in Fall River and St. Elizabeth’s Medical Center in Brighton.

While changing Steward’s rating outlook, Moody’s last week affirmed the health care system’s rating at B3.

“Moody’s has affirmed Steward’s existing rating in spite of a challenging operating environment facing all health care providers. Steward’s financials have improved, including demonstrating positive cash flow and reduction in debt. The company is in a stronger position than it was a year ago. For anyone following the health care industry, remaining stable in this environment is a success,” said Brooke Thurston, a spokeswoman for Steward Health Care, in a statement.

Analysts said improvements in Steward’s operating results would take longer to realize than expected, citing operations “with very high leverage and limited ability to repay debt through free cash flow due to continued weak volume trends and increased restructuring efforts.”

Moody’s called the operating environment for hospitals in eastern Massachusetts “challenging” in part due to individuals deferring or foregoing non-urgent care due to higher deductibles and copayments.

“The shift of responsibility of payment to the patient also results in shifting the collection burden for the patient portion to the hospital operators,” Moody’s wrote in an April 12 credit opinion. “We also expect that the shift toward lower cost settings will continue to depress inpatient admissions as services move to outpatient settings.”

Moody’s also concluded the slower pace of improvements in Steward’s operating results would make complying with financial covenants “less certain” over the next 12 to 18 months.

An affiliate of Cerberus Capital Management L.P., Steward was formed in March 2010 to operate an integrated care and community hospital network that includes 10 acute care hospitals and one long-term acute care hospital.

As state policymakers continue implementation of health care access, cost control and care delivery laws - including integration of the federal Affordable Care Act - the health care market in Massachusetts has undergone many changes, with care providers forming strategic alliances through business deals and mergers.

Tufts Medical Center and Lowell General Hospital on Monday announced plans to form a new health system to “foster collaboration between and among community-based and academic medical providers to effectively identify patient needs and manage the health of the communities they serve.” The organizations will align with a new parent company led by Normand Deschene, of Lowell General, as chief executive officer and Ellen Zane as chairperson.

After nearly four weeks without emergency medical services in the region, hundreds of residents and nurses from North Adams visited the State House Tuesday demanding the Patrick administration speed up the process to reopen an emergency room at North Adams Regional Hospital.

“I would like the governor to do something right away. It is a health care crisis,” said Robbin Simonetti, a nurse who worked in the day surgery department.

Karin Robert, who was also a registered nurse at the hospital, said, "People are showing up at the ER and it’s closed. So they are driving to the local ambulance dispatch.”

Colleen Quinn contributed reporting.