Richard Leuchter, the lead author of the paper and an assistant professor at the David Geffen School of Medicine at UCLA, told the Globe occupancy is calculated by dividing the number of admitted patients at a hospital with staffed hospital beds, meaning beds that are open, available and ready to be used where a patient can be treated by a nurse and a doctor.

The research revealed that the US had a mean bed occupancy of about 64 percent prior to the pandemic. That went up to 75 percent in the year after the official end of the pandemic. Meanwhile, there was a 16 percent decline in health care workers staffing beds during the same period.

The concern, Leuchter said, is that with demographic trends showing that adults over 65 years old will outnumber children under 18 by 2035, hospitals around the country could face significant pressure.

“That is a huge, unprecedented, demographic shift,” he told the Globe. “What that means is that as the population ages, the need for hospitalizations will also increase. Older adults are hospitalized at five times higher than their younger counterparts.”

This could mean that by 2032, the US could hit 85 percent hospital occupancy, a threshold that experts use to determine that a country is experiencing bed shortages.

Massachusetts and Rhode Island registering the highest post-pandemic hospital occupancy suggests that they are at the highest risk of getting to that level, Leuchter said.

“Which is kind of a scary prospect,” he told the Globe.

Hitting that 85 percent threshold removes a safety buffer for hospitals, especially when faced with unexpected surges, such as a pandemic or a natural disaster.

It may also lead to longer wait times before patients can see a doctor, which could exacerbate the stresses on health care workers.

“All those physicians are going to be overburdened. The nurses are going to be stretched thin. The pharmacists are going to be feeling the impacts of that,” Leuchter said. “All of that basically has the potential to lead to more adverse events in the hospital, more medication errors, more delays in care, things of that nature that can have real impact on patients.”

Leuchter pointed out that high occupancy appeared to be driven by a decline in staff at hospitals and not by a rise in the number of patients admitted for care. But another additional factor could be due to an increase in hospital closures and bankruptcies seen across the country, driven in part by what he said was private equity’s foray into healthcare.

“So that’s another issue here. So when we talk about staffed hospital bed shortage, it’s the actual people, but it’s the bed themselves, and we have to address both of those things to avoid a hospital bed shortage,” Leuchter said.

The prospect of a bed shortage hitting the country could be accelerated by how sick people get over the coming years, with trends showing that obesity levels and Americans with cardiovascular diseases rising.

“If people get drastically sicker over the next decade and require more hospitalizations that could precipitate a hospital bed shortage, make it happen even sooner,” Leuchter told the Globe.

But on the flip side, if medical breakthroughs come to the fore that help the country get healthier, it could help delay states hitting that threshold, he added.

One thing that could help, Leuchter said, is an initiative being tried at UCLA called Next Day Clinic, where patients who need more time at a hospital can be referred to specialized clinics, a process than can free up beds at facilities.

“That’s another thing nationally we can implement these models to reduce the demand for hospital beds by about 10 percent over the next decade,” he said. “That’s enough to avoid this potential shortage.”

John Hancock of the Globe Staff contributed to this report.

Omar Mohammed can be reached at omar.mohammed@globe.com. Follow him on Twitter (X) @shurufu.