A. The Quality Data Model (QDM) is a conceptual data model that helps measure developers and implementers understand the general concepts needed to compute a quality measure. However, QDM only defines the concepts, such as a diagnosis, or a laboratory test (with a result), or a physical examination finding (such as blood pressure readings). A method to relate each concept to other concepts requires an expression language. As an example, the QDM data element is similar to a noun in expressing grammar (e.g., a laboratory test) and related adjectives (the time the laboratory test was performed). But to create a sentence, one must have verbs (e.g., starts) and adverbs (after the beginning of). The expression language provides the verbs and adverbs. Prior versions of QDM (version 4.3 and earlier) included the expression language and the conceptual data model. The expression language portion of QDM was difficult to understand and more challenging to compute. So, Clinical Quality Language (CQL) was developed as a way to express what was needed. CQL can express that some specific activity happened during an inpatient encounter and that it happened before another activity. However, CQL needs a data model to indicate what is related to what.
- CQL defines the expression – i.e., the relationship between item A and item B
- QDM defines the items
- CQL can work with other data models. It is not restricted to QDM. However, in the current CMS measure development activities, QDM is the chosen data model to work with CQL. Other projects could consider other data models.
In the Health Level Seven International (HL7) community, efforts have progressed to try to define a standard data model. One effort reviewed the QDM and also a data model created by the Clinical Decision Support Workgroup called virtual medical record (vMR). After coordinating the concepts from QDM and vMR, the HL7 effort created a new model, based on the Fast Healthcare Interoperability Resources (FHIR) content. This new model is called Quality Improvement (QI)-Core – the FHIR extension that describes how to use FHIR resources to express a quality measure or a clinical decision support artifact. However, QI-Core is not something that can be used directly in a computer model. So tooling was developed to create a model that can be used to help author measures or clinical decision support artifacts. The QI-Core model thus appears in a logical view for use – that logical view is called QUICK (Quality Improvement and Clinical Knowledge). So, QI-Core is the FHIR-based data model and QUICK is a more usable view and version of QI-Core. However, QUICK (which is also logical view of QI-Core) represents the nouns and CQL expression language is needed to create full queries.
Thus, CQL and QDM is currently in use to create quality measures in the CMS activities for electronic clinical quality measures (eCQMs). CQL and QUICK (which is also logical view of QI-Core) can be used to create eCQMs and clinical decision support artifacts. Note that using QUICK requires that the system implemented must be able to understand HL7 FHIR. QUICK provides some ‘extensions’ to FHIR by further clarifying some of the metadata (adjectives) to help make the descriptions clearer.