The paradigm changes health systems are faced with result in highly complex and distributed systems requiring flexibility, autonomy, but first of all advanced interoperability. In that context, understanding the architecture of the system to be supported as well as the process to meet the intended business objectives is crucial. Unfortunately, there is a lot of confusion around the term architecture, which doesn't facilitate the integration of systems. Using a reference architecture model and framework, relevant existing architectural approaches are analyzed, compared and critically discussed, but also harmonized using a reference architectural model and framework.