U.S. District Judge B. Lynn Winmill ruled that the St. Luke's Health System's 2012 acquisition of the Saltzer Medical Group risked driving up the price of healthcare unnecessarily.
"There are other ways to achieve the same effect that do not run afoul of the antitrust laws and do not run such a risk of increased costs," Winmill said in his ruling.
The Wall Street Journal reported Friday that the ruling, a win for the Federal Trade Commission, fits in with a recent streak of FTC victories in hospital mergers cases brought on anti-trust grounds, but that attorneys looked at the case in Idaho as a litmus test for how the federal courts would view mergers with doctor groups.
The FTC said the acquisition would drive up insurance costs, because less competition would allow the hospital to raise its prices.
The hospital said acquisition of the 40-doctor group by the St. Luke's Health System would help integrate healthcare services in the area, the Journal said.