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BMJ. 2018 Oct 18;363:k4011. doi: 10.1136/bmj.k4011.

Association between patient outcomes and accreditation in US hospitals: observational study.

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Department of Radiation Oncology, Brigham and Women's Hospital/Dana Farber Cancer Institute, Boston, MA, USA.
Department of Health Policy and Management, Harvard T H Chan School of Public Health, Boston, MA 02115, USA.
Department of Medicine, Harvard Medical School, Boston, MA, USA.
Department of Medicine, Division of General Internal Medicine, Brigham and Women's Hospital, Boston, MA, USA.
Department of Biostatistics, Harvard T H Chan School of Public Health, Boston, MA, USA.
Department of Health Policy and Management, Harvard T H Chan School of Public Health, Boston, MA 02115, USA



To determine whether patients admitted to US hospitals that are accredited have better outcomes than those admitted to hospitals reviewed through state surveys, and whether accreditation by The Joint Commission (the largest and most well known accrediting body with an international presence) confers any additional benefits for patients compared with other independent accrediting organizations.


Observational study.


4400 hospitals in the United States, of which 3337 were accredited (2847 by The Joint Commission) and 1063 underwent state based review between 2014 and 2017.


4 242 684 patients aged 65 years and older admitted for 15 common medical and six common surgical conditions and survey respondents of the Hospital Consumer Assessment of Healthcare Provider and Systems (HCAHPS).


Risk adjusted mortality and readmission rates at 30 days and HCAHPS patient experience scores. Hospital admissions were identified from Medicare inpatient files for 2014, and accreditation information was obtained from the Centers for Medicare and Medicaid Services and The Joint Commission.


Patients treated at accredited hospitals had lower 30 day mortality rates (although not statistically significant lower rates, based on the prespecified P value threshold) than those at hospitals that were reviewed by a state survey agency (10.2% v 10.6%, difference 0.4% (95% confidence interval 0.1% to 0.8%), P=0.03), but nearly identical rates of mortality for the six surgical conditions (2.4% v 2.4%, 0.0% (-0.3% to 0.3%), P=0.99). Readmissions for the 15 medical conditions at 30 days were significantly lower at accredited hospitals than at state survey hospitals (22.4% v 23.2%, 0.8% (0.4% to 1.3%), P<0.001) but did not differ for the surgical conditions (15.9% v 15.6%, 0.3% (-1.2% to 1.6%), P=0.75). No statistically significant differences were seen in 30 day mortality or readmission rates (for both the medical or surgical conditions) between hospitals accredited by The Joint Commission and those accredited by other independent organizations. Patient experience scores were modestly better at state survey hospitals than at accredited hospitals (summary star rating 3.4 v 3.2, 0.2 (0.1 to 0.3), P<0.001). Among accredited hospitals, The Joint Commission did not have significantly different patient experience scores compared to other independent organizations (3.1 v 3.2, 0.1 (-0.003 to 0.2), P=0.06).


US hospital accreditation by independent organizations is not associated with lower mortality, and is only slightly associated with reduced readmission rates for the 15 common medical conditions selected in this study. There was no evidence in this study to indicate that patients choosing a hospital accredited by The Joint Commission confer any healthcare benefits over choosing a hospital accredited by another independent accrediting organization.

Conflict of interest statement

Competing interests: All authors have completed the ICMJE uniform disclosure form at and declare: no support from any organization for the submitted work; no financial relationships with any organizations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

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