library CMS146_QDM version '2'

/*
 * This take differs from the original in that it uses a function for the
 * repeated timing logic between the encounter and pharyngitis.
 */

using QDM version '5.0.2'

valueset "Acute Pharyngitis": '2.16.840.1.113883.3.464.1003.102.12.1011'
valueset "Acute Tonsillitis": '2.16.840.1.113883.3.464.1003.102.12.1012'
valueset "Ambulatory/ED Visit": '2.16.840.1.113883.3.464.1003.101.12.1061'
valueset "Antibiotic Medications": '2.16.840.1.113883.3.464.1003.196.12.1001'
valueset "Group A Streptococcus Test": '2.16.840.1.113883.3.464.1003.198.12.1012'

parameter MeasurementPeriod Interval<DateTime>

context Patient

define "InDemographic":
  AgeInYearsAt(start of MeasurementPeriod) >= 2 and AgeInYearsAt(start of MeasurementPeriod) < 18

define "Pharyngitis":
  ["Diagnosis": "Acute Pharyngitis"] union ["Diagnosis": "Acute Tonsillitis"]

define "Antibiotics":
  ["Medication, Order": "Antibiotic Medications"] M

define function isRelated(P "Diagnosis", E "EncounterPerformed") :
  P.prevalencePeriod includes E.relevantPeriod
    or P.prevalencePeriod starts during E.relevantPeriod

define "MeasurementPeriodEncounters":
  ["Encounter, Performed": "Ambulatory/ED Visit"] E
    where "InDemographic"
      and E.relevantPeriod during MeasurementPeriod

define "PharyngitisEncounters":
  "MeasurementPeriodEncounters" E
    with "Pharyngitis" P such that isRelated(P, E)
    with "Antibiotics" A such that A.authorDatetime 3 days or less after start of E.relevantPeriod

define "PharyngitisWithPriorAntibiotics":
  "Pharyngitis" P
    with "Antibiotics" A such that A.authorDatetime 30 days or less before start of P.prevalencePeriod

define "ExcludedEncounters":
  "PharyngitisEncounters" E
    with "PharyngitisWithPriorAntibiotics" P such that isRelated(P, E)

define "StrepTestEncounters":
  "PharyngitisEncounters" E
    with ["Laboratory Test, Performed": "Group A Streptococcus Test"] T
      such that T."result" is not null
        and T.relevantPeriod starts within 3 days of E.relevantPeriod

define "IPPCount":
  Count("PharyngitisEncounters")

define "DenominatorCount":
  "IPPCount"

define "DenominatorExclusionsCount":
  Count("ExcludedEncounters")

define "NumeratorCount":
  Count("StrepTestEncounters" except "ExcludedEncounters")