Evaluating The Role Of Payment Policy In Driving Vertical Integration In The Oncology Market.

The health care industry has experienced massive consolidation over the past decade. Much of the consolidation has been vertical (with hospitals acquiring physician practices) instead of horizontal (with physician practices or hospitals merging with similar entities). We documented the increase in vertical integration in the market for cancer care in the period 2003-15, finding that the rate of hospital or health system ownership of practices doubled from about 30 percent to about 60 percent. The two most commonly cited explanations for this consolidation are a 2005 Medicare Part B payment reform that dramatically reduced reimbursement for chemotherapy drugs, and the expansion of hospital eligibility for the 340B Drug Discount Program under the Affordable Care Act (ACA). To evaluate the evidence for these explanations, we used difference-in-differences methods to assess whether consolidation increased more in areas with greater exposure to each policy than in areas with less exposure. We found little evidence that either policy contributed to vertical integration. Rather, increased consolidation in the market for cancer care may be part of a broader post-ACA trend toward integrated health care systems.