Efrem Castillo, M.D. currently serves as Chief Medical Officer for Medicare and Retirement. As Chief Medical Officer, Dr. Castillo serves as the clinical liaison with the Center for Medicare and Medicaid Services (CMS) and is responsible for all clinical product and program offerings, clinical market strategies and analysis to support improved clinical quality outcomes and lower costs. Dr. Castillo started practicing medicine in 1995 after completing his Medical School training and Family Practice residency at The University of Texas Health Science Center at San Antonio. Dr. Castillo has practiced in a variety of practice, from a hospitalist to hospice. He started his own practice with multiple locations that was acquired by WellMed Medical Management in 2010. Prior to joining UnitedHealthcare, Dr. Castillo served as Regional Medical Director for WellMed Medical Management where he led all the Quality and Care Management programs.