QDM Definition (QDM Version 5.3):
Coded diagnoses/problems addressed during the encounter. The diagnoses attribute is intended to capture ALL diagnoses, including principal diagnosis. Use of the Encounter, Performed: diagnoses attribute and the Diagnosis datatype is redundant for relating the diagnosis to the Encounter, Performed. The Encounter, Performed: diagnoses syntax is preferred. Referencing the same diagnosis using Encounter, Performed (diagnoses attribute) and Diagnosis (datatype) should only occur if the measure must define a specified length of a prevalence period, e.g., the measure must assure that the diagnoses have been present for at least some defined time period before the encounter, and were addressed during the Encounter.