MDRD (Modification of Diet in Renal Disease study)

Creatinine-based eGFR equation from patients with chronic kidney disease

Biomarkers
Creatinine
Validated for
Adults (no age range declared)
Inputs
Age, Sex, Creatinine (optional: Race)
Reports
mL/min/1.73 m²
Published
2006

The eGFR guide explains which equation the calculator suggests and indexed and absolute GFR.

Formula

eGFR=175×Scr−1.154×age−0.203×(0.742 if female)×(1.212 if Black)\text{eGFR} = 175 \times S_{cr}^{-1.154} \times \text{age}^{-0.203} \times (0.742 \text{ if female}) \times (1.212 \text{ if Black})

As text: eGFR = 175 × SCr^(-1.154) × Age^(-0.203) × (0.742 if female) × (1.212 if Black)

Constants

SymbolMeaningValue
175Base coefficient (IDMS-standardized)
−1.154Creatinine exponent
−0.203Age exponent
Sex factorSex-dependent multiplier
Female: 0.742
Male: 1.000
Race factorRace-dependent multiplier
Black: 1.212
Other: 1.000
ScrS_{cr}Serum creatinine (IDMS-standardized) (input)mg/dL
AgePatient age (input)years

How it was developed

Developed in 1,628 patients with predominantly nondiabetic chronic kidney disease enrolled in the MDRD Study, a randomised trial at 15 clinical centres, with GFR measured as urinary clearance of ¹²⁵I-iothalamate. The 4-variable equation was later re-expressed for serum creatinine calibrated to an assay traceable to isotope-dilution mass spectrometry.

Clinical notes

  • Simplified 4-variable version of the 6-variable MDRD Study equation
  • Includes coefficients for female sex and Black race
  • Original samples assayed by kinetic alkaline picrate, recalibrated to IDMS-traceable enzymatic assay

Limitations

  • Few study participants had measured GFR above 90 mL/min/1.73 m²
  • Larger errors versus measured GFR when eGFR is 60 mL/min/1.73 m² or above
  • Inaccurate with low creatinine generation, such as muscle wasting or reduced meat intake

References

  1. Levey AS, et al. Using standardized serum creatinine values in the modification of diet in renal disease study equation for estimating glomerular filtration rate. Ann Intern Med. 2006;145(4):247-54. doi:10.7326/0003-4819-145-4-200608150-00004

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