Should patients that are deceased be removed from the initial population?  A deceased patient no longer has an age.  The initial population reads: Initial Population

• AgeInYearsAt(date from
  end of "Measurement Period"
  )in Interval[18, 75]
  and exists ( "Qualifying Encounters" )
  and exists ( ["Diagnosis": "Diabetes"] Diabetes
  where Diabetes.prevalencePeriod overlaps "Measurement Period"
  )