The Index Event Date definition indicates that the first instance of an elevated PHQ9 event during the denominator identification period is the inclusion criteria. Does this only include patients whose first ever recorded elevated PHQ9 score which falls during the denominator identification period? Or can patients with a history of major depression have a prior history of elevated PHQ9 scores beginning prior to the denominator identification period be included as well, with the index event being the earliest elevated PHQ9 specifically during the denominator identification period?

For example, a patient with an active diagnosis of major depression beginning 6 months prior to the denominator identification period and an elevated PHQ9 score 5 months prior to the denominator identification period. Would this patient be included in the denominator of this measure if they had an elevated PHQ9 during the denominator identification period? Or are they excluded because their first instance of an elevated PHQ9 score was prior to the denominator identification period?