Thomas Diemer, MD


Phone: (573) 803-8777
| Fax: (317) 633-4878

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About Thomas

Thomas Diemer, M.D., has served in various roles in the health care industry for over 30 years. From a traditional private internal medicine practice to serving as Medical Director and Chief Medical Officer for Saint Francis Healthcare System, Dr. Diemer has expertise in value-based strategy, physician leadership, population health and clinical pathways. 

As an advisor for Hall Render Advisory Services, Dr. Diemer brings his extensive experience and knowledge to clients within the health care industry. He has a proven track record of success in developing and implementing innovative solutions that improve patient outcomes and reduce costs. Dr. Diemer is committed to delivering exceptional service to clients and making a positive impact on the health care industry. 


  • University of Illinois, B.S. - 1984; University of Illinois, M.D. - 1988


  • American College of Physicians
  • American Academy of Physician Leadership
  • American Red Cross
  • Healthy Communities Coalition


  • Private practice, internal medicine 1991-2008
  • Medical Director, Saint Francis Medical Center 2008-2015
  • Chief Medical Officer, Saint Francis Medical Center 2015-2021
  • President Saint Francis Medical Partners 2015-2021
  • Secretary, Saint Francis Medical Staff 2002-2003
  • Vice President, Saint Francis Medical Staff 2004-2005
  • President, Saint Francis Medical Staff 2006-2007
  • Chair, Credentials Committee, Saint Francis Medical Center 2004-2005
  • Chair, Department of Medicine, Saint Francis Medical Center, 2008-2010
  • Chair, Section of Internal Medicine, Saint Francis Medical Center, 2002-2008
  • Chair, Section of Internal Medicine, Southeast Missouri Hospital, 1999-2008
  • Member, Credentials Committee, Southeast Missouri Hospital, 1996-2008