Define Population of Interest

Define Population of Interest

Parameters to consider:

  • Encounter type (for research questions limited to patient location)
    • Type of admission (e.g. inpatient, outpatient, surgery)
  • Patient characteristics
    • Patient demographics (e.g. age)
  • Time frame
    • All available records
    • Within a specific timeframe (YYYY-MM-DD to YYYY-MM-DD)
    • For variables that may have multiple entries per patient (e.g. multiple glucose measurements per hospitalization), you can request: only the last entry, the first entry, or all entries for the visit
  • An index event
    • All patients with a specific ICD9 code
    • CPT procedure code
    • Lab entry (e.g. fasting glucose)
  • Supply codes (when possible) for medical entities requested.
    • For example, if requesting all patients with a diagnosis of hypertension, supply the ICD9 code “401.”
    • The following are appropriate terminologies for various entities:
      1. Diagnoses: ICD9
      2. Procedures: ICD9 or CPT code
      3. Labs: MED codes if possible
    • The East, West, and Allen campuses all use separate codes for labs, so you may need to clarify your request with a programmer once one has been assigned to you.
    • For any request, MED codes are also highly encouraged to be included.

Tip: Using the RedX query combiner tool can get you a rough idea on sample size within the CDW. Since RedX is a 5% random sample, your eventual sample size would be approximately the sample size from RedX times 20.

  • Find Columbia Doctors