Following the mass shooting in Las Vegas earlier this week, hundreds of gunshot victims were sped to local hospitals. Some have since been released; those with more serious injuries are still being treated. Understanding the full extent of their medical needs will take years, even lifetimes. Many, almost certainly, face a long, painful recovery — and mounting medical bills.

There has been scant research on the physical and financial toll of being shot. But three major studies published this year help describe one significant part of the picture: the cost of providing hospital care in the immediate aftermath of a bullet injury. The sums spent to treat shooting victims are staggering, the research reveals, with the burden falling on medical facilities, insurance companies, taxpayers, and the survivors themselves.

In March, an analysis from researchers at the Stanford University School of Medicine estimated the initial hospitalization cost of firearm injuries at $735 million per year. In August, research from the University of Iowa estimated the average annual cost of hospital admission to be $622 million.

The most recent study, released last week, comes from three researchers at Johns Hopkins University School of Medicine. The yearly charges associated with treating gunshot patients in American hospitals, they determined, is nearly $3 billion.

The new Hopkins study goes beyond the earlier studies, capturing charges for emergency department treatment as well as inpatient charges. Using data from the Healthcare Cost and Utilization Project, the largest collection of hospital-care data in the United States, the authors analyzed records of 150,930 gunshot patients between 2006 and 2014. They examined patient demographics like age and sex, as well as the type of firearm, circumstances of the shooting, and discharge status.

“There is a minimal amount of evidence that exists when it comes to firearm injury, from a research perspective,” said Joseph Sakran, an assistant professor in the Johns Hopkins Department of Surgery and one of the study’s co-authors. The study, he said, was an effort to “contribute and add to the literature, both from a human suffering perspective and also from an economic perspective.”

Sakran has an unusually personal tie to the issue he studies. At the age of 17, he was hit in the throat by a stray bullet. The experience moved him to become a trauma surgeon.

He and his co-authors found that over the nine-year study period, firearm injuries accounted for an estimated $24.9 billion in emergency department and inpatient charges — which comes out to $2.8 billion per year.

The discharge findings from the Hopkins study offer clues into what gunshot patients face after being initially treated in the emergency department, and the charges for different services.

Nearly half of gunshot patients were treated in the emergency department and sent home. The average charge for each of these patients was $5,254. More than a third of patients — 37 percent — were admitted to the hospital, which includes those who stayed just one night, as well as those kept longer to undergo multiple operations. Those admitted for inpatient care incurred charges 18 times higher than those who were treated in the emergency room and released: $95,887 per patient, on average.

Another 8 percent of patients were discharged to additional-care facilities, which could include rehabilitation centers that treat spinal-cord or traumatic brain injuries, or other types of acute physical-rehab facilities.

A significant proportion of the patients analyzed in the Hopkins study had either had no healthcare coverage or were categorized as self-pay. The study, published in Health Affairs, notes that the total hospital charges do not represent the actual cost associated with firearm injuries.

As with earlier research, the Johns Hopkins team found that gunshot survivors skew heavily male. The rate of gun injuries was nine times higher for men than for women. Young men in particular are at risk, with those between the ages of 20 and 24 arriving in the emergency department with a gunshot wound at a rate of 152.8 per 100,000 people, compared to the average rate of 25.3 per 100,000 for all demographics.

The majority of gunshot wounds stemmed from assaults, and most were caused by handguns, the research found. Assault was the most common circumstance of injury among patients enrolled in Medicaid or labeled self-pay.

The authors noted that the results likely underestimate the true financial burden and prevalence of firearm injuries. The data didn’t factor in patients who died before reaching the hospital, or gunshot patients who survived but didn’t come to the hospital at all; nor did it account for the price of subsequent needs like physical therapy, trauma counseling, or in-home care.

Survivors of gun assaults are at high risk of being shot again, so understanding more about the patients who sustain even minor wounds can help hospitals and advocates know where to focus prevention efforts, Sakran said. “What we don’t want to see is those people coming back, and next time having lethal injuries,” he said.