Physicians who choose to partner with DaVita have direct access to some of the world’s leading clinical experts in various areas of kidney care. DaVita’s clinical leadership team—including the Office of the Chief Medical Officer (OCMO), group medical directors and our physician partners—works together to identify, shape and drive the patient programs that are implemented in our more than 2,305 dialysis centers.
When determining our approach to care at DaVita, our clinical leadership team continuously innovates new and improved ways to address patients’ kidney care issues and their health-related quality of life.
DaVita’s Office of the Chief Medical Officer is composed of a group of experienced nephrologists committed to providing value for patients, delivering high-quality care, improving clinical outcomes and being responsible stewards of resources. OCMO focuses on the needs of DaVita’s medical directors and physician partners by strengthening clinical and operational partnerships and developing new tools and resources to help tackle the daily challenges in kidney care.
Mahesh Krishnan, MD, MPH, MBA, FASN | Chief Medical Officer, International; Group Vice President of Research and Development
Before joining DaVita Kidney Care, Mahesh Krishnan, M.D., served as medical director and global development leader for Epogen, where he played a key role in discussions with the FDA and the Centers for Medicare and Medicaid Services. He also assisted as executive director of medical policy for Amgen, and had a private practice in Virginia for nearly five years. He currently serves on the editorial board of Nephrology News and Issues and his writing has been published many times in renal care and research publications around the world. Dr. Krishnan earned his medical degree from Thomas Jefferson University, and holds a master's degree in Public Health from Johns Hopkins University and an MBA in Medical Services Management from the Johns Hopkins Carey School of Business.
Allen R. Nissenson, MD, FACP, FASN, FNKF | Chief Medical Officer, United States | @DrNissenson
Prolific author and renowned authority on kidney disease, Allen R. Nissenson, M.D., is emeritus professor of medicine at the David Geffen School of Medicine at UCLA, where he has served as director of the dialysis program and associate dean. Dr. Nissenson is also co-chair of the Kidney Care Partners Quality Initiative. He is a former president of the Renal Physicians Association (RPA) and served on the RPA Board of Directors as a special advisor to the president. Dr. Nissenson is a past president of the Southern California End-Stage Renal Disease Network. He is the author of more than 650 scientific papers and the editor of two dialysis textbooks, both in their 4th editions.
Stephen McMurray, MD, FACP | Vice President, Clinical Integrated Care Management Services
Stephen D. McMurray, M.D., began his career at Indiana Medical Consultants, a 35-physician multi-specialty group in Fort Wayne, Indiana. In 1996, Dr. McMurray became a founding member of Renal Care Group (RCG) and later a formal board member. He is a former Renal Physicians Association Board member, and received his medical degree from the Indiana University School of Medicine.
Mark Kaplan, MD | Vice President, Medical Affairs
Mark R. Kaplan, MD, previously practiced nephrology in Nashville, Tennessee, where he launched and developed the practice's clinical research program. He served as the vice president of clinical research at Renal Care Group and Fresenius Medical Care, and was chief medical officer at DSI Renal, Inc. before joining DaVita Kidney Care. Dr. Kaplan earned his medical degree at Vanderbilt University, and then completed a year as chief resident in internal medicine at the Nashville Veterans Affairs Medical Center, and a clinical and research fellowship in nephrology and hypertension at Harvard University Medical School's Brigham and Women's Hospital in Boston.
Robert Provenzano, MD, FACP, FASN | Vice President, Medical Affairs | @DrBobPro
Robert Provenzano, M.D., is a clinical professor of medicine at Wayne State University School of Medicine in Detroit, where he earned his medical degree. He completed his fellowship training at Henry Ford Hospital and served as the chief of the section of nephrology, hypertension and transplantation and director of nephrology research at St. John Hospital and Medical Center in Detroit. Dr. Provenzano is past president of the Renal Physicians Association and Chair of the National Kidney Foundation (NKF) of Michigan. He recently stepped down as the CEO of St. Clair Specialty Physicians, PC, a multistate nephrology practice. He has published extensively on kidney care business models and currently oversees Nephrology Practice Solutions (NPS), a national kidney care practice management solution affiliated with DaVita. He also serves as the medical director of DaVita hospital services, which supports more than 1,000 hospital acute dialysis programs.
David B. Van Wyck, MD | Vice President, Clinical Support Services
David B. Van Wyck, M.D., is emeritus professor of medicine and surgery at the University of Arizona College of Medicine, where he received his medical degree. He was also past co-chair of the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF-KDOQI) Anemia Workgroup. Dr. Van Wyck has written or contributed to publications on basic iron metabolism and reticuloendothelial function, and on clinical aspects of iron and anemia in patients with chronic kidney disease.
John Robertson, MD | Vice President, Clinical Support Services
John A. Robertson, M.D., is founder and partner of Nephrology Associates Medical Group, Inc., the third largest nephrology group in the state of California. He has been a member of DaVita Kidney Care's Physician Council for several years, is a medical director for the DaVita Kidney Care—SCAN CMS ESRD Demonstration Project and is affiliated with Apex Research of Riverside, a private practice participating in clinical trials.
Robert Merrell, MD, FACP | Vice President, Clinical Risk Support
Robert Merrell, M.D., has been a private-practice nephrologist for 25 years, serving patients at Kidney Specialists of Southern Nevada for most of that time. He has served as medical director at several DaVita Kidney Care centers over the years and now oversees DaVita’s Siena Henderson Dialysis Center in Henderson, Nevada. He is board-certified in nephrology and internal medicine, a fellow in the American College of Physicians, and received his medical degree from the University of Oklahoma Health Sciences Center, Department of Medicine.
Martin Schreiber, MD | Vice President, Clinical Affairs – Home Dialysis
Martin Schreiber, M.D., came to DaVita Kidney Care with nearly 40 years of experience in nephrology. Before this this role, he worked primarily with Cleveland Clinic and held a number of key positions there, including Member Board of Governors, Chairman of the Department of Nephrology and Hypertension and the Director of Home Dialysis. Additionally, he is an active educator and international lecturer, with previous editorial responsibilities with the Journal of the American Society of Nephrology, American Journal of Kidney Disease and Peritoneal Dialysis International. Dr. Schreiber received his medical degree through Wake Forest University School of Medicine.
Steven M. Brunelli, MD, MSCE | Vice President and Medical Director of Health Economics and Outcomes Research
Prior to joining DaVita Clinical Research, Steven M. Brunelli, M.D., was a faculty member at Harvard Medical School and the Brigham and Women’s Hospital, where he directed an active clinical research group that focused on chronic kidney disease, pharmacoepidemiology and pharmacoeconomics, dialysis outcomes epidemiology and the hospital’s dialysis service. He also served on the American Society of Nephrology’s Dialysis Advisory Group and its Comparative Effectiveness Taskforce. Dr. Brunelli has published more than 90 peer reviewed publications, and serves on editorial boards at the Journal of the American Society of Nephrology and the American Journal of Kidney Diseases. He completed medical school at the University of Pennsylvania, earned a Master of Science degree in Clinical Epidemiology and served as faculty at University of Pennsylvania.
Lorne Holland, M.D. | Chief Laboratory Officer, DaVita Labs
Prior to joining DaVita Labs, Lorne Holland, M.D., served as a medical director for the west region of Quest Diagnostics. Before that, he held medical directorship positions at PathGroup, a regional reference laboratory providing clinical and anatomic pathology services, and at the University of Colorado Hospital. He earned his medical degree at the University of Illinois and MBA from Amberton University.
John R. Wigneswaran, MD | Vice President, Clinical Affairs – Hospital Services | @doctorWIG
John R. Wigneswaran, M.D., received his medical degree from Tufts University School of Medicine, renal fellowship from Cornell University and MBA from the Massachusetts Institute of Technology. Before joining DaVita Kidney Care, Dr. Wigneswaran served as Medical Director in Medical Affairs for Johnson and Johnson, Chief Medical Officer for CHF Solutions, Inc./Gambro and Vice President of Market Development at Fresenius Medical Care. He was certified by both the Boards of Internal Medicine and Nephrology and is a member of the American Society of Nephrology. In addition, Dr. Wigneswaran founded Nephroceuticals, an organization focused on improving nutritional health of patients with chronic diseases.
Stefan H Jacobson, MD, PhD | CEO And Professor Of Nephrology, Danderyd University Hospital
Professor Jacobson, in addition to being CEO and professor of nephrology at Danderyd University Hospital, is the associate editor of the Scandinavian Journal of Urology. Prior to Danderyd University Hospital, Professor Jacobson served first as the Head of the medical division and then as the director of the nephrology Department at Karolinksa Hospital and Korolinksa Institute. He has written or contributed to over 150 publications in journals around the world, and focuses his research on inflammation and cardio-vascular disease, leukocyte function, transmigration of leukocytes, IgA nephropathy and cardio renal syndrome. Professor Jacobson also serves on several international study and steering committees, with a focus on the randomized controlled study of the effects of hemodialysis (membrane permeability outcome study, MPO study), the practice pattern in hemodialysis (dialysis outcome practice pattern study, DOPPS), and the effects of cinacalcet (ECHO).
Maciej Drożdż, MD, PhD | Chief Medical Officer, Europe and the Middle East; Medical Director, Poland
As Chief Medical Director for DaVita’s operations in Europe and the Middle East, Dr. Drożdż worked for more than 20 years at University Hospital in Kraków and served as the head of the dialysis unit in the department of nephrology. He has written or contributed to nearly 40 journal publications, including six chapters in polish nephrological textbooks. His research focuses on cardiovascular challenges for dialysis patients and intradialytic anticoagulation. As both principal and co-investigator he took part in phase II, III and IV clinical trials.
André Weigert, MD, PhD | Chief Medical Officer, Portugal
Born in Rio de Janeiro, Brazil, Dr. André Weigert studied at the University of Lisbon, Portugal, before doing postgraduate training at Hospital S. Maria and Hospital Santa Cruz in Lisbon, Portugal, and Baylor College of Medicine in Houston, Texas. His professional credits include chief medical resident at the VAMC of Houston/BCM, the fellowship in nephrology at the University of Colorado, Denver and specialist degrees in internal medicine and nephrology (1996) and clinical pharmacology (2008). Additionally, Dr. Weigert obtained certification from the American Board of Internal Medicine (1992) and the American Board of Nephrology and Hypertension (1996), and was elected fellow of the American College of Physicians (1999). His work on more than 40 published studies (in English, Portuguese and French) includes several clinical studies involving the EVOLVE trial. Dr. Weigert currently works in the renal transplant unit of the Hospital Santa Cruz, is assistant professor of pharmacology at the University of Lisbon and is the Chief Medical Officer of DaVita in Portugal. He directs the dialysis unit, Eurodial, at Obidos-Gaeiras, with 170 patients—all of whom are doing online hemodiafiltration (HDF). He is also involved in studies of pulse wave velocity in patients undergoing HDF, as well as new approaches to anemia management. He participated in several ISN CMEs in African countries (including Angola, Mozambique, Zambia, Democratic Republic of Congo).
Abdulkareem Alsuwaida, MD, FRCPC, MSc | Chief Medical Officer, Saudi Arabia
Dr. Abdulkareem Alsuwaida is currently a professor of medicine and director of postgraduate education at King Saud University in Riyadh. He is also a consultant in the Division of Nephrology at the King Khalid University Hospital. Dr. Alsuwaida earned a medical degree from King Abdulaziz University and completed postgraduate medical education in internal medicine and nephrology at the University of Toronto. Additionally, he earned a master's degree in clinical epidemiology from the University of Toronto. A past president of the Saudi Society of Nephrology, Dr. Alsuwaida's research is focused on dialysis, glumerulonephritis and lupus nephritis. He has published more than 40 papers on these topics.
Sylvia P. B. Ramirez, MD, MPH, MBA | Chief Medical Officer, Asia Pacific
Dr. Sylvia P. B. Ramirez is a clinical nephrologist and a population epidemiologist with more than 20 years of research, public policy and nephrology experience. Before becoming the chief medical officer for DaVita in Asia Pacific she was vice president of global research and development for Arbor Research Collaborative for Health, and remains a consultant there. She was principal investigator and coinvestigator for multiple projects for the United States Centers for Medicare & Medicaid Services, including the Evaluation of ESRD Disease Management Demonstration, the Quality Incentive Payment Demonstration and the ESRD Measures Support Work. She is also a coinvestigator for the Dialysis Outcomes and Practice Patterns Study. Dr. Ramirez has published multiple papers on ESRD care, and has led a variety of technical expert panels on the development of quality performance measures in U.S. dialysis facilities.
Mauricio Ruiz Martinez, MD I Chief Medical Officer, Colombia
Dr. Mauricio Ruiz Martinez has been Chief Medical Officer for DaVita in Colombia since 2013. Previously he served as Associate Professor Chair of Nephrology and Semiology on the faculty of medicine at Universidad del Rosario and at La Fundación Universitaria de Ciencias de la Salud, both in Bogotá, and served as director of dialysis services at San José Hospital for more than 10 years. Additionally, Dr. Ruiz was coordinator of the peritoneal dialysis programs at Fresenius Colombia from 2004 to 2009 and was a Genzyme renal advisor from 2008 to 2010. He has also contributed chapters to many books on internal medicine and nephrology and is coeditor of the latest edition of the nephrology text in the Collection of the CIB (Corporación de Investigaciones Biológicas) in Colombia.
Suresh Sankar, MD, MBBS, MBA, FRCP, FASN | Medical Director, India
Dr. Suresh Sankar has 16 years of experience as a Clinical Nephrologist and was a group medical director for 3 years. He is certified by the American Board of Nephrology and the American Board of Internal Medicine. An alumnus of Madras Medical College, Dr. Sankar completed his nephrology training at the University of Rochester in New York and is a Fellow of American Society of Nephrology and Fellow of the Royal College of Edinburgh. He has a keen interest in clinical research, epidemiology, and health systems and has published more than 50 original papers and abstracts on those topics. He was honored with the Indian Society of Nephrology’s Young Investigator Award and Janssen-Cilag Award of Excellence in 2006.
Werner Kleophas, MD, PhD | Chief Medical Officer, Germany
Professor Dr. Werner Kleophas’s career began in the mid 1980’s in the medical department of Ferdinand Sauerbruch Klinikum Wuppertal (Wuppertal, Germany). From there, he advanced to Deutsches Diabetes Forschungsinstitut Düsseldorf and Nephrological Clinic Heinrich Heine Universität Düsseldorf before starting work as a nephrologist and diabetologist in 1990 at Gemeinschaftspraxis (Düsseldorf, Germany), where his work continues today and where he took part in the development of the Genius dialysis machine. In addition, Professor Kleophas is a fellow of the American Society of Nephrology and sits on numerous editorial boards dedicated to nephrology and diabetology. Professor Kleophas was also among the first in Germany to establish combined programs for patients with diabetes mellitus and chronic kidney disease. His range of experience, coupled with his deep understanding of clinical trials (comprising authorship of numerous publications), serve him well in his role as chief medical officer of DaVita in Germany.
Grace Yan, MD, PhD | Medical Director, China
Before joining DaVita Kidney Care, Dr. Grace Yan worked at the prestigious Shanghai Renji Hospital, a class 3A hospital in China, where she spent 22 years in nephrology, including a post-doctoral year at the Renal Disease and Hypertension Department of the University of Colorado Health Science Center, Denver, Colorado. Dr. Grace earned her MD and PhD from Shanghai Jiao Tong University School of Medicine, where she currently advises MSc and PhD candidates. She is also a committee member of the Chinese Society of Internal Medicine and was a Youth Committee member of the Chinese Society of Nephrology. She has won a number of academic awards and has published extensively.