Using MIMIC data

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Understanding how to join data across different MIMIC modules and tables.

Key Identifiers

Patient Level

  • subject_id: Unique patient identifier across all modules
  • Links: All tables contain this identifier

Hospital Admission Level

  • hadm_id: Hospital admission identifier
  • Links: Hospital and ICU modules

ICU Stay Level

  • stay_id: ICU stay identifier
  • Links: ICU-specific tables

Common Linking Patterns

Hospital to ICU Data 

-- Example: Link admissions to ICU stays
SELECT a.*, i.*
FROM mimiciv_hosp.admissions a
LEFT JOIN mimiciv_icu.icustays i
  ON a.hadm_id = i.hadm_id;

Patient Demographics 

-- Example: Add patient demographics to any analysis
SELECT analysis.*, p.gender, p.anchor_age
FROM your_analysis_table analysis
LEFT JOIN mimiciv_hosp.patients p
  ON analysis.subject_id = p.subject_id;

Module-Specific Linking

Patients can be linked across distinct MIMIC databases using their identifier. Databases which can currently be linked include MIMIC-IV, MIMIC-IV-ED, MIMIC-IV-ECG, MIMIC-IV-Note, and MIMIC-CXR.

  • Hospital (hosp): subject_id, hadm_id
  • ICU: subject_id, hadm_id, stay_id
  • Emergency Department (ED): subject_id, hadm_id
    • the hadm_id in the MIMIC-IV-ED edstays table is the hospitalization immediately after the ED stay
  • Chest X-ray (CXR): subject_id in MIMIC-IV is equal to the PatientID metadata element in the DICOM headers of the chest x-rays in MIMIC-CXR
  • ECG: subject_id links to MIMIC-IV; note_id links cardiologist notes in the MIMIC-IV-Note module
  • Note: subject_id, hadm_id