Carlin Caroline S, Feldman Roger, Dowd Bryan
Medica Research Institute, Minnetonka, Minnesota, USA.
University of Minnesota, Minneapolis, Minnesota, USA.
Health Econ. 2017 Dec;26(12):1789-1806. doi: 10.1002/hec.3502. Epub 2017 May 4.
When a clinic system is acquired by an integrated delivery system (IDS), the ownership change includes both vertical integration with the hospital(s), and horizontal integration with the IDS's previously owned or "legacy" clinics, causing increased market concentration in physician services. Although there is a robust literature on the impact of hospital market concentration, the literature on physician market concentration is sparse. The objective of this study is to determine the impact on physician prices when two IDSs acquired three multispecialty clinic systems in Minneapolis-St Paul, Minnesota at the end of 2007, using commercial claims data from a large health plan (2006-2011). Using a difference-in-differences model and nonacquired clinics as controls, we found that four years after the acquisitions (2011), average physician price indices in the acquired clinic systems were 32-47% higher than expected in absence of the acquisitions. Average physician prices in the IDS legacy clinics were 14-20% higher in 2011 than expected. Procedure-specific prices for common office visit and inpatient procedures also increased following the acquisitions.
当一个诊所系统被一个综合医疗服务系统（IDS）收购时，所有权变更既包括与医院的纵向整合，也包括与IDS之前拥有的或“传统”诊所的横向整合，这导致医生服务市场的集中度提高。虽然有大量关于医院市场集中度影响的文献，但关于医生市场集中度的文献却很少。本研究的目的是利用来自一个大型健康计划（2006 - 2011年）的商业理赔数据，确定2007年末两个IDS在明尼苏达州明尼阿波利斯 - 圣保罗收购三个多专科诊所系统时对医生价格的影响。使用差异中的差异模型并以未被收购的诊所作为对照，我们发现收购四年后（2011年），被收购诊所系统中的平均医生价格指数比没有收购情况下预期的高32% - 47%。2011年，IDS传统诊所的平均医生价格比预期高14% - 20%。收购后，普通门诊和住院手术的特定程序价格也有所上涨。
