UnitedHealth Group's Optum is taking over a California health system's information technology and back office functions as part of a new model that will allow the healthcare giant to manage “all non-clinical work” for a local medical provider. The deal announced Wednesday will allow Optum to take on John Muir Health’s key "nonclinical functions" including information technology, revenue cycle management, analytics, purchasing and claims management of a healthcare system that boasts a network of more than 1,000 physicians and two large hospitals east of San Francisco.