The plans operate using high deductibles and personal health accounts like HSAs.
The smaller number of encounters with healthcare providers accounted for about two-thirds of the system's overall savings, materials from RAND stated. Enrollees were also less likely to visit specialists and use brand-name drugs.
These choices did not come without concern from study authors.
"What we don't yet know is whether the healthcare that was eliminated was unnecessary," Sood said.
Amelia Haviland, the study's leader, added: "The goal is to get patients to think critically about their care, not reduce high-value care that can keep them healthy."
Cancer screenings and routine testing for diabetes patients were among the preventive services declined by enrollees, who were also less likely to choose to admit themselves to hospitals.
"Consumer-directed health plans can clearly have a significant impact on costs, at least in the short term," Haviland said. "What we don’t yet know is whether the cutbacks in care they trigger could result in poorer health or health emergencies down the road."
The study was conducted using claims filed between 2003 and 2007 with 59 large U.S. employers. It was sponsored by the California Healthcare Foundation and the Robert Wood Johnson Foundation.