CEC-UW Strengths and Limitations

CEC-UW Strengths

  • Very Large and Varied Population:
    • More than 1.8 million discrete patients meeting the COVID-19 case definition included in sample since February 1, 2020
    • 21 different health systems from across the nation with diverse populations
  • The Potential of Longitudinal Data: Because each patient maintains a unique identifier and health system data were updated regularly, we can:
    • Evaluate the frequency and types of re-treatment (inpatient or outpatient) for both COVID-19 and non-COVID-19 illnesses after the original COVID-19 diagnosis over the 24 months of data collection.
    • Assess the evolution of the disease and its treatments on outcomes (e.g., changes in death rates within and across health systems).
  • Limited Data Set: In calendar year 2020, data were entirely de-identified, HIPPA compliant. In calendar year 2021, the data set was transformed to a limited data set allowing for collection of dates of service and five-digit zip code.
  • Extensive Array of Data Elements: Approximately 250 discrete EHR data elements provide the capacity to examine relations between these variables and outcomes.
  • Regular Data Pulls Retrospective to February 1, 2020: Health system data has been extracted regularly since February 1, 2020. These repeated data extractions allow for the addition and refinement of data elements over time to:
    • Add data elements of interest (e.g., vaccine data, Remdesivir, neurologic symptoms).
    • Improve accuracy of data elements collected (e.g., COVID-19 diagnostic criteria, death definition).

CEC-UW Limitations

  • Data transferCOVID-19 Cases Only: The cohort is limited to individuals diagnosed with COVID-19; thus, we are unable to examine the risk of developing COVID-19 or compare findings of cohort members to individuals without a COVID-19 diagnosis.
  • Discrete Data Elements Only: The data pulled is almost exclusively limited to discrete EHR data elements. It typically does not include data from text fields within the EHR.
  • Missing Data: For many EHR data elements (e.g., vaping), a large proportion of patients have no data reported.
  • Harmonizing EHR Data across Health Systems: Merging data from different health systems highlights the idiosyncratic nature of how each system records EHR data, even if on the same EHR platform (e.g., Epic)
  • Patient Data is limited to Health System Where COVID-19 Was Diagnosed: Thus, if patient dies or subsequently receives care at an alternative health system, those events are not captured.

CEC-UW Essentials

1.8 million+ COVID-19 Patients

21 Health Systems

Examine Discreet EHR Data