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UPMC Announces New President of Medical Group in Central Pa.


March 30, 2022

Jason Marx, MD, MBA

HARRISBURG, Pa. — UPMC recently announced the appointment of Jason Marx, M.D., M.B.A, to succeed Robert Nielsen, M.D., as president of the PinnacleHealth Medical Group.

Dr. Marx most recently served as senior vice president of physician integration and value-based care and chief of the University of Maryland Medical System (UMMS) critical care COVID-19 operations. In addition, Dr. Marx served as the inaugural chair of the UMMS physician network management committee. He is also an adjunct assistant professor of medicine at the University of Maryland School of Medicine.

"With more than 20 years of progressive clinical and operational leadership at the University of Maryland Medical System and St. Joseph Medical Center, Dr. Marx brings a wealth of expertise to this role,” said Phil Guarneschelli, president, UPMC in Central Pa.

Dr. Marx earned his undergraduate degree at Princeton University. He received his medical degree from Georgetown University School of Medicine. He completed his residency at Stanford University Medical Center and obtained a post-doctoral fellowship in critical care, pulmonary, and sleep medicine at Johns Hopkins University School of Medicine. He also holds a master of business administration degree from Loyola University Maryland.

Robert Nielsen, M.D., president, PinnacleHealth Medical Group, UPMC in Central Pa., will retire on March 31, 2022. Dr. Nielsen joined UPMC, along with his practice, Annville Family Medicine, in January 2015, 37 years after founding the practice. Dr. Nielsen joined the PinnacleHealth Medical Group as head of population health and became the area's director in June 2016. Dr. Nielsen has been published in numerous journals and has served as a medical consultant and a co-investigator for research grants. He has presented across the country on topics relating to the Affordable Care Act, myocardial infarction, and an aging population.

"We are excited for Dr. Nielsen as he moves on to this new chapter of his life, but he will be deeply missed as a colleague, friend, and major contributor to the health and well-being of our region,” said Guarneschelli.

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