Emergency patients of similar ages and similar injuries were 16 percent more likely to survive if flown instead of driven to the hospital, according to the research led by clinical researcher Adil Haider at Johns Hopkins University School of Medicine.
Haider and colleagues examined the survival rates for more than 223,000 severely injured patients transported by either helicopter or ground emergency services.
The Journal of the American Medical Association published the results Tuesday.
Haider said that previous studies examined survival rates but were limited because of missing data, as well as a bias that helicopter-transported patients already tend to be more severely injured.
There's such a difference between groups of patients transported via air versus ground transport, Haider said in a phone interview.
Other studies attempted to correct this bias using a technique called logistic regression. Haider and his colleagues used a different method called propensity score matching, a more upfront method of ensuring that other factors such as age or gender don't influence the analysis.
It balances the groups in such a way that the only difference ends up being that one group came by helicopter transport and the other came by ground transport, Haider said.
The group concluded that one in 65 significantly injured patients brought to a trauma center with the highest level of surgical care by helicopter would have died if an ambulance had been their only option.
Helicopters are costly. In Maryland, where the study took place, helicopters cost $5,000 per patient on average of public funds. Haider said that the additional costs get balanced out.
For those hypothetical 65 air-transported patients, the cost of saving that one life works out to be around $325,000.
That's not a very high number if you compare it to the cost of a couple years of dialysis, a procedure that runs between $50,000 and $70,000 per year, Haider said.