Metadata such as topics, levels, keywords, categories, objectives, difficulty and similar content, are features in some learning management systems. However, none of these LMSs provided the necessary web services to support publishing and retrieval of metadata.
Meanwhile, most publishers and other instructors use the General Feedback field for storing metadata related to the question as it is a cross-platform compatible method including IMS QTI. The Respondus->Edit->Search and Advanced Search can be used for locating questions based on keywords in the General Feedback.
Also, some instructors and publishers will use some type of naming convention in the question titles to organize questions by categories, topics or learning objectives. For most learning management systems, the question titles are never seen by students.