Leadership Team
The legacy and collaboration of our leadership sets us apart. This team has dedicated their careers to creating the best organization where providers can thrive.

Mark Gilreath
Chief Executive Officer
Mark Gilreath brings more than 27 years of operational leadership, innovation, and GI experience to United Digestive’s executive team. As former operating partner for Frazier Healthcare Partners, he facilitated the formation of United Digestive in 2018.

Neal C. Patel, MD
President
Embracing the dyad leadership model which partners physician and business leaders, Dr. Patel serves as President of United Digestive. Prior to assuming the role, Dr. Patel first served as Vice President of Clinical Development, followed by the position of Chief Strategy Officer. He is currently a partner physician and also serves as a member of the physician executive committee for Atlanta Gastroenterology Associates. Dr. Patel represents United Digestive on a national level as a board member of the Digestive Health Provider Association (DHPA) and as a member of the American College of Gastroenterology’s Practice Management Committee.

John Suh, MD, MPH
Chief Medical Officer
Prior to serving as chief medical officer at United Digestive, Dr. John Suh held various leadership roles within the organization and affiliated practice, Atlanta Gastroenterology Associates. He served as a member of United Digestive’s inaugural physician executive committee, on the organization’s endoscopy governing body, and continues to serve as medical director for the organization’s Advanced Center for GI Therapeutics. In addition, he is a former board member of the Digestive Health Provider Association, an organization comprised of independent GI practices from across the nation.

Edward L. Hay, Jr., MHA, FACHE
Chief Operations Officer
Edward brings more than 32 years of operations and physician practice management experience to United Digestive, including expertise in strategic planning, governance, recruiting and retention, referral management, and revenue cycle infrastructure.
Previously, Edward worked for Optum/The Advisory Board Company/Southwind for 12 years where he served in various key executive roles and provided group practice assessment and strategic planning to health systems and medical group enterprises. Most recently, he served as Senior Vice President of Operations for ProHEALTH New York, a 1,000-clinician medical group. He oversaw all practice operations, urgent care, radiology, pathology, anesthesia, ambulatory surgery center, and all centralized practice services (call center, health information management, and referral management).

Ron Fleming
Chief Financial Officer
Ron brings more than 30 years of revenue cycle management, accounting, and financial planning experience to United Digestive’s executive team, including more than 20 years serving in a Chief Financial Officer role within the healthcare industry.
Most recently, he served as the CFO for Prospira PainCare, Inc., a private equity-backed, multi-state provider of comprehensive, multidisciplinary pain management services. He previously held CFO roles with AdCare Health Systems, a long-term care provider, and Georgia Cancer Specialists, one of the Top 10 private oncology practices in the US.

Sam Vaill
Chief Development Officer
Sam brings nearly 20 years of experience in business development, healthcare, mergers & acquisitions, private equity, and investment banking to the United Digestive executive team.
Most recently, Sam served as Chief Growth Officer for Sequel Youth & Family Services, one of the largest national providers of residential and community-based behavioral health services for children, adolescents, and adults. He oversaw various business development teams and was responsible for organic growth, mergers & acquisitions, and de novo expansion. Sam was also responsible for helping start and set the strategy for their new Autism division.
Board of Directors
A culture of collaboration and accountability starts at the top. Our board of directors is comprised of cross-functional business and clinical leaders who help guide our organization and ensure we continue to accomplish our goals.
Physician Executive Committee
With a dynamic and engaged provider base, our physician executive committee serves as the voice for their local colleagues and helps guide the clinical side of the organization. Members are elected by their peers, represent our various geographic regions, and meet regularly with United Digestive’s leadership team.