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The Impact of Hospital Mergers on Treatment Intensity and Health Outcomes
Author(s) -
Hayford Tamara B.
Publication year - 2012
Publication title -
health services research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.706
H-Index - 121
eISSN - 1475-6773
pISSN - 0017-9124
DOI - 10.1111/j.1475-6773.2011.01351.x
Subject(s) - medicine , health services research , intensity (physics) , medline , emergency medicine , nursing , public health , physics , quantum mechanics , political science , law
Objective To analyze the impact of hospital mergers on treatment intensity and health outcomes. Data Hospital inpatient data from C alifornia for 1990 through 2006, encompassing 40 mergers. Study Design I used a geographic‐based IV approach to determine the effect of a zip code's exposure to a merger. The merged facility's market share represents exposure, instrumented with combined premerge shares. Additional specifications include H erfindahl I ndex ( HHI ), instrumented with predicted change in HHI . Results The primary specification results indicate that merger completion is associated with a 3.7 percent increase in the utilization of bypass surgery and angioplasty and a 1.7 percent increase in inpatient mortality above averages in 2000 for the average zip code. Isolating the competition mechanism mutes the treatment intensity result slightly, but it more than doubles the merger exposure effect on inpatient mortality to a 3.9 percent increase. The competition mechanism is associated with a sizeable increase in number of procedures. Conclusions Unlike previous studies, this analysis finds that hospital mergers are associated with increased treatment intensity and higher inpatient mortality rates among heart disease patients. Access to additional outcome measures such as 30‐day mortality and readmission rates might shed additional light on whether the relationship between these outcomes is causal.