baseline-creatinine

name	baseline-creatinine
description	Estimate baseline serum creatinine for AKI assessment in MIMIC-IV. Use for KDIGO staging, AKI research, or renal function baseline establishment.
license	Apache-2.0
metadata	{"author":"m4-clinical-extraction","version":"1.0","database":"mimic-iv","category":"derived-concepts","source":"https://github.com/MIT-LCP/mimic-code/tree/main/mimic-iv/concepts/measurement","validated":true}

Baseline Creatinine Estimation

Estimates the patient's baseline (pre-illness) serum creatinine, which is critical for accurate AKI staging. The true baseline is often unknown; this query uses a hierarchical approach.

When to Use This Skill

• KDIGO AKI staging (requires baseline comparison)
• AKI research cohorts
• Chronic kidney disease identification
• Renal function trajectory analysis

Baseline Determination Rules

The baseline creatinine is determined hierarchically:

1. If lowest admission creatinine <= 1.1 mg/dL: Use the lowest value (assumed normal)
2. If patient has CKD diagnosis: Use the lowest admission value (even if elevated)
3. Otherwise: Estimate baseline using MDRD equation assuming GFR = 75 mL/min/1.73m^2

Pre-computed Table

SELECT
    hadm_id,
    gender,
    age,
    scr_min,      -- Lowest creatinine during admission
    ckd,          
    mdrd_est,     
    scr_baseline  
 mimiciv_derived.creatinine_baseline;