• Clinical Leadership

    With significant experience and expertise, our physician leaders collaborate with other nephrologists to transform kidney care.

Clinical Leadership Team

DaVita-affiliated physicians have access to DaVita’s Office of the Chief Medical Officer (OCMO) physician leaders to collaborate and receive input whenever needed. Dedicated to improving kidney care and the lives of patients, OCMO leaders oversee initiatives such as:

  • Developing a transformative vision of improved health care
  • Collaborating with the nephrologist community
  • Taking accountability for improving results
  • Addressing challenging clinical topics
  • Investing in physician development across all levels
  • Striving for a high level of physician satisfaction
Clinical Leadership Team

Office of the Chief Medical Officer

Jeffrey Giullian, MD, MBA, FASN

Chief Medical Officer, DaVita Kidney Care

  • Board of Directors Member, Renal Physicians Association
  • Chairman, Healthcare Payment Committee

George R. Aronoff, MD, MS, FACP, FASN

Vice President of Clinical Affairs, DaVita Kidney Care

  • Former CEO, Renal Ventures Management
  • Former faculty, Indiana University School of Medicine

Bryan N. Becker, MD, MMM, FACP, CPE

Chief Medical Officer, Integrated Kidney Care, DaVita Kidney Care

  • Former President, National Kidney Foundation
  • Former CEO, University of Illinois Hospital and Clinics

Steven M. Brunelli, MD, MSCE

Vice President and Medical Director, DaVita Health Economics and Outcomes Research

  • Former Faculty, Harvard Medical School and Brigham and Women’s Hospital
  • Former Member, American Society of Nephrology’s Dialysis Advisory Group

Partha Das, MBBS, MRCP (Neph), MSc

Chief Medical Officer, DaVita International

  • Consultant Nephrologist, King's College Hospital, London, UK
  • Former Harkness Fellow in Health Care Policy and Practice, Harvard University

Mark R. Kaplan, MD

Vice President, DaVita Medical Affairs

  • Former Chief Medical Officer, DSI Renal, Inc.
  • Former Vice President, Fresenius Medical Care

Mahesh Krishnan, MD, MPH, MBA, FASN

Group Vice President, Research and Development

  • Former founding International Chief Medical Officer, DaVita
  • Former Medical Director and Global Development Leader, Epogen at Amgen

David L. Mahoney, MD

Chief Medical Officer, Lifeline Vascular Access Care

  • Former group medical director, DaVita Kidney Care
  • Former Army physician

Robert Merrell, MD, FACP

Vice President, DaVita Clinical Risk Support

  • Private Practice Nephrologist, Kidney Specialists of Southern Nevada
  • Former Medical Director, DaVita Kidney Care centers

Allen R. Nissenson, MD, FACP, FASN, FNKF

Emeritus CMO, DaVita Kidney Care

  • Emeritus Professor of Medicine, David Geffen School of Medicine
  • Co-Chair, Kidney Care Partners Quality Initiative

Thao Pascual, MD

Chief Medical Officer, Nephrology Practice Solutions

  • Graduate of Harvard Medical School
  • Practicing nephrologist at Snohomish Kidney Institute

John A. Robertson, MD

Vice President, DaVita Clinical Support Services

  • Physician Council Member, DaVita Kidney Care
  • Founder and Partner, Nephrology Associates Medical Group, Inc.

David A. Roer, MD, FACP, FAHA, FASN

Vice President, Medical Affairs, DaVita Integrated Care

  • Associate clinical professor, Yale School of Medicine
  • Previous Chief of Nephrology, St. Mary's Hospital

Martin Schreiber, MD

Chief Medical Officer, Home Modalities

  • Former Chairman, Cleveland Clinic Department of Nephrology and Hypertension
  • Former Director, Cleveland Clinic Home Dialysis

Francesca Tentori, MD, MSCI

Vice President, DaVita Outcomes Research and Patient Empowerment

  • Former research scientist, Arbor Research Collaborative for Health
  • Former assistant medical director, Dialysis Clinic Inc.

David B. Van Wyck, MD

Vice President, DaVita Clinical Support Services

  • Emeritus Professor of Medicine and Surgery, University of Arizona College of Medicine
  • Former Co-Chair, National Kidney Foundation Kidney Disease Outcomes Quality Initiative Anemia Workgroup

Adam Weinstein, MD

Vice President, DaVita Medical Affairs and Clinical IT Services

  • AMA RUC advisor, Renal Physicians Association
  • Former VP of medical affairs, University of Maryland, Shore Regional Health