(Reuters Health) - Immigrants use fewer healthcare services and account for less spending by public and private insurance programs than people born in the U.S., according to a study that suggests the foreign-born may be subsidizing care for other patients.

FILE PHOTO: The women's medical room is seen at the Adelanto immigration detention center, which is run by the Geo Group Inc (GEO.N), in Adelanto, California, U.S., April 13, 2017. REUTERS/Lucy Nicholson

Immigrants’ healthcare utilization was only one-half to two-thirds as high as that of people born in the U.S., the study found. While undocumented immigrants had by far the lowest healthcare use, even immigrants who attained U.S. citizenship still used less healthcare than people born in the country.

In particular, undocumented immigrants account for 1.4 percent of total medical expenditures in the U.S. even though they make up five percent of the population, the analysis found.

And immigrants paid more out-of-pocket than people born in the U.S.

“In the public debate, immigrants, particularly those that are undocumented, have been blamed for the rising cost of healthcare,” said lead study author Lila Flavin of Tufts University School of Medicine in Boston.

“The most surprising finding is that immigrants subsidize healthcare for U.S. born individuals by paying in more to the system than they withdraw,” Flavin said by email.

For the study, Flavin and colleagues examined data from 16 studies published since 2000 looking at variation in healthcare expenditures based on immigration and citizenship status in the U.S.

In three studies that tracked expenditures over time, increases were steeper for citizens than for non-citizens. Between 1999 and 2006, average annual spending for undocumented immigrants, for example, increased by $500 while spending for people born in the U.S. increased by $1,000.

Based on data from 2000 to 2008, spending averaged $1,836 for undocumented immigrants, $3,737 for foreign-born citizens, and $4,478 for people born in the U.S.

Public health insurance programs like Medicaid also spent less on immigrants than on other patients, which might be because non-citizens are not always eligible for this coverage.

One limitation of the study is that it’s difficult to accurately assess how much free care is provided to immigrants, the authors note. Researchers also lacked data on health spending for immigrant children and on any spending for care immigrants may have received outside the U.S.

“When immigrants avoid public services, due to immigration fears or language barriers or lack of providers near their homes, they often visit private pay doctors in their communities,” said Steven Wallace, associate director of the Center for Health Policy Research at the University of California Los Angeles.

“They also sometimes seek care when they are visiting their home countries and pay cash,” Wallace, who wasn’t involved in the study, said by email. “The very low rates of insurance for undocumented immigrants means that most of their care is paid for out of pocket.”

When they arrive in the U.S., immigrants are also healthier than the typical U.S. citizen, said Dr. Robert Fowler, a public health researcher at the University of Toronto who wasn’t involved in the study.

“It is ironic that the immigrant and migrant population is often excluded from participating in public and private health insurance plans,” Fowler said by email.

“This is exactly the healthy population that most plans would want to encourage to enroll, Fowler added. “On average they are healthier and will make money for the plan and subsidize healthcare for the rest of the population.”

SOURCE: bit.ly/2OWR8tM International Journal of Health Services, online August 8, 2018.