About Our Leadership Team

Mark H. Uffer, Chief Executive Officer

Mark H. Uffer, Chief Executive Officer

Mark Uffer was appointed Chief Executive Officer (CEO) and Managing Director of Corona Regional Medical Center in October 2013. 

He holds a Master of Health Care Administration from Chapman University in Orange, California and Bachelor of Business and Management from the University of Redlands in Redlands, California. In addition, he is a Registered Respiratory Therapist, having trained at San Bernardino Valley College in San Bernardino, California.

Mr. Uffer is a healthcare executive with 44 years of clinical and operational experience and has a proven track record of exceptional results. His experience covers public sector as well as investor-owned and not-for-profit healthcare systems. In addition, Mr. Uffer served as the Chief Administrative Officer for the County of San Bernardino and was named the Inland Empire’s Leader of Distinction in 2002.


Mitch Winnik, Chief Operating Officer

Mitch Winnik, Chief Operating Officer

Mitch Winnik has been in the healthcare industry for over 20 years. He started his career in 1990 as a bedside respiratory therapist. Mr. Winnik honorably served as a medical officer in the United States army for six years and supported the war casualties at Brook Army Medical Center where he had oversight of cardiac, pulmonary, and neurology services. After discharging from the service, Mr. Winnik went back to being a bedside clinician and moved in progressively larger roles in progressively larger hospitals until becoming a Hospital Administrator in 2014.

Mr. Winnik has been with UHS since 2015 where he served as an Associate Administrator at Wellington Regional Medical Center in Palm Beach, Florida until 2016. He joined Corona Regional Medical Center June 2016 as the Chief Operating Officer. Mr. Winnik has a deep passion to optimize the patient’s experience and to always ensure that a healthy team work environment is a top priority.


Kim Colonnelli, Chief Nursing Officer

Kim Colonnelli, Chief Nursing Officer

Kim Colonnelli was appointed to the Chief Nursing Officer position at Corona Regional Medical Center in 2015.

Prior to that, Ms. Colonnelli served as Chief Nursing Officer at Palomar Health for a number of years. Her clinical background is emergency and trauma nursing and she held several director level positions in both the Los Angeles and San Diego areas.

Ms. Colonnelli is a diploma graduate from the LA County-USC Medical Center. She holds a BSN from the University of the State of New York and a Master’s Degree in business from Phoenix University.

She is a graduate of the Wharton Nurse Executive Fellowship program and is board certified through the American Nurse Credentialing Center as a nurse executive.  She brings a wealth of experience and knowledge to Corona Regional.


Kanner Tillman, Chief Financial Officer

Kanner Tillman, Chief Financial Officer

Kanner Tillman has been Chief Financial Officer of Corona Regional Medical Center since December 2016. 

Kanner holds a Doctorate in Public Policy from Claremont Graduate University in Claremont, California and an MBA from the California State University in Fullerton, California.

Mr. Tillman is a financial executive with 25 years of experience in Southern California hospitals, ambulatory services and HMOs. Prior to Corona Regional he has worked at several integrated investor-owned and not-for-profit healthcare systems and payers, including Kaiser Permanente and Blue Cross of California.