Hospital Mergers and Quality of Care

A new study looks at the quality of care at hospitals acquired in a recent wave of consolidations

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The quality of care at hospitals acquired during a recent wave of consolidations has gotten worse or stayed the same, according to a study led by Harvard Medical School scientists published Jan. 2 in NEJM.

The findings deal a blow to the often-cited arguments that hospital consolidation would improve care. A flurry of earlier studies showed that mergers increase prices. Now after analyzing patient outcomes after hundreds of hospital mergers, the new research also dashes the hopes that this more expensive care might be of higher quality.

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“Our findings call into question claims that hospital mergers are good for patients—and beg the question of what we are getting from higher hospital prices,” said study senior author J. Michael McWilliams, the Warren Alpert Foundation Professor of Health Care Policy in the Blavatnik Institute at HMS and an HMS professor of medicine and a practicing general internist at Brigham and Women's Hospital.

McWilliams noted that rising hospital prices have been one of the leading drivers of unsustainable growth in U.S. health spending.   

To examine the impact of hospital mergers on quality of care, researchers from HMS and Harvard Business School examined patient outcomes from nearly 250 hospital mergers that took place between 2009 and 2013. Using data collected by the Centers for Medicare and Medicaid Services, they analyzed variables such as 30-day readmission and mortality rates among patients discharged from a hospital, as well as clinical measures such as timely antibiotic treatment of patients with bacterial pneumonia. The researchers also factored in patient experiences, such as whether those who received care at a given hospital would recommend it to others. For their analysis, the team compared trends in these indicators between 246 hospitals acquired in merger transactions and unaffected hospitals.

The verdict? Consolidation did not improve hospital performance, and patient-experience scores deteriorated somewhat after the mergers.

The study was not designed to examine the reasons behind the worsening in patient experience. Weakening of competition due to hospital mergers could have contributed, the researchers said, but deeper exploration suggested other potential mechanisms. Notably, the analysis found the decline in patient-experience scores occurred mainly in hospitals acquired by hospitals that already had a poor patient-experience score—a finding that suggests acquisitions facilitate the spread of low quality care but not of high quality care.

The researchers caution that isolated, individual mergers may have still yielded positive results—something that an aggregate analysis is not powered to capture. And the researchers could only examine measurable aspects of quality. The trend in hospital performance on these standard measures, however, appears to point to a net effect of overall decline, the team said.

“Since our study estimated the average effects of mergers, we can't rule out the possibility that some mergers are good for patient care," said first author Nancy Beaulieu, research associate in health care policy at HMS. "But this evidence should give us pause when considering arguments for hospitals mergers.”

The work was supported by the Agency for Healthcare Research and Quality (grant no. U19HS024072).
Co-investigators included Bruce Landon and Jesse Dalton from HMS, Ifedayo Kuye, from the University of California, San Francisco, and Leemore Dafny from Harvard Business School and the National Bureau of Economic Research.