Brief description of measure CMS816/HH-01: Hospital Harm- Severe Hypoglycemia: The proportion of inpatient hospitalizations for patients 18 years of age or older at admission, who were administered at least one hypoglycemic medication during the encounter, who suffer the harm of a severe hypoglycemic event during the encounter. Harm (numerator) is defined as a laboratory or point-of-care (POC) test for blood glucose with a result less than 40 mg/dL, where the hypoglycemic medication was given within the 24 hours prior to the start of the low blood glucose event (and administered during the encounter). Only one severe hypoglycemic event is counted per inpatient hospitalization encounter. Description of issue ​A recent Jira question submitted by a vendor noted there were issues with the performance of CMS816 due to data volumes at their clients sites, as the current logic pulls every lab value in a patient's history. The submitter provided suggestions on how to revise the logic to reduce the volume of data the CQL query processor has to consider when evaluating the "Severe Hypoglycemic Harm Event" expression in the measure. Goal of review Obtain technical feedback

Proposed solution ​Revise the current CQL definition "Encounter With Severe Hypoglycemic Harm Event" by creating separate definitions for the hypoglycemic medications, initial glucose and follow-up glucose exam like so: CURRENT LOGIC: define "Encounter With Severe Hypoglycemic Harm Event" "Encounter With Hypoglycemic Medication Administration" QualifyingEncounter   where exists ( ["Laboratory Test, Performed": "Glucose Lab Test Mass Per Volume"] BloodGlucoseLab1       with ["Medication, Administered": "Hypoglycemics Severe Hypoglycemia"] HypoglycemicMed         such that Global."NormalizeInterval" ( HypoglycemicMed.relevantDatetime, HypoglycemicMed.relevantPeriod ) starts 24 hours or less before or on BloodGlucoseLab1.relevantDatetime           and Global."NormalizeInterval" ( HypoglycemicMed.relevantDatetime, HypoglycemicMed.relevantPeriod ) starts during Global."HospitalizationWithObservation" ( QualifyingEncounter )       without ["Laboratory Test, Performed": "Glucose Lab Test Mass Per Volume"] BloodGlucoseLab2         such that BloodGlucoseLab2.relevantDatetime during Global."HospitalizationWithObservation" ( QualifyingEncounter )           and BloodGlucoseLab2.relevantDatetime 5 minutes or less after BloodGlucoseLab1.relevantDatetime           and BloodGlucoseLab2.result > 80 'mg/dL'       where BloodGlucoseLab1.relevantDatetime during Global."HospitalizationWithObservation" ( QualifyingEncounter )         and BloodGlucoseLab1.result < 40 'mg/dL' ) PROPOSED LOGIC DEFINITIONS AND FUNCTIONS: define function "Blood Glucose Labs"(QualifyingEncounter "Encounter, Performed"):   ["Laboratory Test, Performed": "Glucose lab test"] BloodGlucoseLab     where     BloodGlucoseLab.relevantDatetime during Global."HospitalizationWithObservation" ( QualifyingEncounter )     and BloodGlucoseLab.result < 40 'mg/dL' define function "Followup Glucose Lab"(QualifyingEncounter "Encounter, Performed"):   ["Laboratory Test, Performed": "Glucose lab test"] FollowupBloodGlucoseLab   where FollowupBloodGlucoseLab.relevantDatetime during Global."HospitalizationWithObservation" ( QualifyingEncounter )     and FollowupBloodGlucoseLab.result > 80 'mg/dL' define function "Hypoglycemic Medications"(QualifyingEncounter "Encounter, Performed"):   "Hypoglycemic Medication Administration" HypoglycemicMeds   where Global."NormalizeInterval" ( HypoglycemicMeds.relevantDatetime, HypoglycemicMeds.relevantPeriod ) starts during Global."HospitalizationWithObservation" ( QualifyingEncounter ) define "Severe Hypoglycemic Harm Event":   "Denominator" QualifyingEncounter     where exists ("Blood Glucose Labs"(QualifyingEncounter) BloodGlucoseLab         with "Hypoglycemic Medications"(QualifyingEncounter) HypoglycemicMeds         such that Global."NormalizeInterval" ( HypoglycemicMeds.relevantDatetime, HypoglycemicMeds.relevantPeriod ) starts 24 hours or less before or on BloodGlucoseLab.relevantDatetime                 without "Followup Glucose Lab"(QualifyingEncounter) FollowupBloodGlucoseLab         such that FollowupBloodGlucoseLab.relevantDatetime 5 minutes or less after BloodGlucoseLab.relevantDatetime ) Rationale for change ​Creating separate definitions for the hypoglycemic medications, initial glucose and follow-up glucose exam and limiting each definition to the encounter timing window and applying the result filter to the lab tests may reduce the volume of data the CQL query processor has to consider when evaluating the "Severe Hypoglycemic Harm Event" expression.