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Original Investigation
May 23/30, 2017

Association Between Teaching Status and Mortality in US Hospitals

Author Affiliations
  • 1Department of Health Policy and Management, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
  • 2Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
  • 3Partnered Evidence-based Policy Resource Center, VA Boston Healthcare System, Boston, Massachusetts
  • 4Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts
  • 5Department of Medicine, Massachusetts General Hospital, Boston
  • 6Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
  • 7Harvard Global Health Institute, Cambridge, Massachusetts
JAMA. 2017;317(20):2105-2113. doi:10.1001/jama.2017.5702
Key Points

Question  Is there a difference in mortality rates at US teaching hospitals compared with other hospitals?

Findings  In an observational study of approximately 21 million hospitalizations of Medicare beneficiaries, adjusted 30-day mortality rates were significantly lower at 250 major teaching hospitals compared with 894 minor teaching and 3339 nonteaching hospitals overall (8.3% vs 9.2% and 9.5%) as well as for several individual common medical and surgical conditions.

Meaning  Major teaching hospital status was associated with lower mortality rates for common conditions.


Importance  Few studies have analyzed contemporary data on outcomes at US teaching hospitals vs nonteaching hospitals.

Objective  To examine risk-adjusted outcomes for patients admitted to teaching vs nonteaching hospitals across a broad range of medical and surgical conditions.

Design, Setting, and Participants  Use of national Medicare data to compare mortality rates in US teaching and nonteaching hospitals for all hospitalizations and for common medical and surgical conditions among Medicare beneficiaries 65 years and older.

Exposures  Hospital teaching status: major teaching hospitals (members of the Council of Teaching Hospitals), minor teaching hospitals (other hospitals with medical school affiliation), and nonteaching hospitals (remaining hospitals).

Main Outcomes and Measures  Primary outcome was 30-day mortality rate for all hospitalizations and for 15 common medical and 6 surgical conditions. Secondary outcomes included 30-day mortality stratified by hospital size and 7-day mortality and 90-day mortality for all hospitalizations as well as for individual medical and surgical conditions.

Results  The sample consisted of 21 451 824 total hospitalizations at 4483 hospitals, of which 250 (5.6%) were major teaching, 894 (19.9%) were minor teaching, and 3339 (74.3%) were nonteaching hospitals. Unadjusted 30-day mortality was 8.1% at major teaching hospitals, 9.2% at minor teaching hospitals, and 9.6% at nonteaching hospitals, with a 1.5% (95% CI, 1.3%-1.7%; P < .001) mortality difference between major teaching hospitals and nonteaching hospitals. After adjusting for patient and hospital characteristics, the same pattern persisted (8.3% mortality at major teaching vs 9.2% at minor teaching and 9.5% at nonteaching), but the difference in mortality between major and nonteaching hospitals was smaller (1.2% [95% CI, 1.0%-1.4%]; P < .001). After stratifying by hospital size, 187 large (≥400 beds) major teaching hospitals had lower adjusted overall 30-day mortality relative to 76 large nonteaching hospitals (8.1% vs 9.4%; 1.2% difference [95% CI, 0.9%-1.5%]; P < .001). This same pattern of lower overall 30-day mortality at teaching hospitals was observed for medium-sized (100-399 beds) hospitals (8.6% vs 9.3% and 9.4%; 0.8% difference between 61 major and 1207 nonteaching hospitals [95% CI, 0.4%-1.3%]; P = .003). Among small (≤99 beds) hospitals, 187 minor teaching hospitals had lower overall 30-day mortality relative to 2056 nonteaching hospitals (9.5% vs 9.9%; 0.4% difference [95% CI, 0.1%-0.7%]; P = .01).

Conclusions and Relevance  Among hospitalizations for US Medicare beneficiaries, major teaching hospital status was associated with lower mortality rates for common conditions compared with nonteaching hospitals. Further study is needed to understand the reasons for these differences.