egfr: Automatically select the best equation to use for estimated glomerular filtration rate (eGFR) calculation.

Description

Automatically select the best equation to use for estimated glomerular filtration rate (eGFR) calculation.

Usage

egfr(scr_uM, age_y, height_m, male, black, ...)
egfr_cockcroft_gault(scr_uM, age_y, weight_kg, male, idms_assay = TRUE,
  ...)
egfr_mdrd(scr_uM, age_y, male, black, idms_assay = TRUE, ...,
  warn_ckdepi_preferred = TRUE)
egfr_ckdepi(scr_uM, age_y, male, black, idms_assay = TRUE, ...,
  warn_mdrd_preferred = TRUE)
egfr_bedside_schwartz(scr_uM, height_m, idms_assay = TRUE, ...)

Arguments

scr_uM

Serum creatinine (in micromoles/L, or 'uM').

age_y

Age in years

height_m

Height in meters

male

Logical, TRUE (male) or FALSE (female)

black

Logical, TRUE (race is Black (African-American in USA) or FALSE

...

passed to subsequent GFR methods (for egfr) or validation (for other functions)

weight_kg

numeric vector of weight(s) in kg

idms_assay

Was an isotope dilution mass spectrometry (IDMS) calibrated assay used for serum creatinine measurement?

warn_ckdepi_preferred

When calculating eGFR > 60, should a warning be generated suggesting CKD-EPI is preferred?

warn_mdrd_preferred

When calculating eGFR < 60, should a warning be generated suggesting MDRD is preferred?

Value

A vector of estimated glomerular filtration rates with units of mL/min/1.73 m^2 (except that the units are mL/min for egfr_cockcroft_gault.

Functions

egfr_cockcroft_gault: The Cockcroft - Gault equation for eGFR (not preferred).
egfr_mdrd: The MDRD equation for eGFR (preferred for adults with eGFR < 60).
egfr_ckdepi: The CKD-EPI equation for eGFR (preferred for adults with eGFR >= 60).
egfr_bedside_schwartz: The Bedside Schwartz equation for eGFR (for children, age less than 18 years).

Details

GFR estimation is not recommended or validated for individuals with unstable creatinine concentration (including pregnancy, serious comorbid conditions, hospitalized patients, patients with acute renal failure) or extremes in muscle mass and diet (including amputees, paraplegics, bodybuilders, or obese patients; or vegetarians or when taking creatine dietary supplements). For more details, please refer to the NIDDK summary on estimating GFR: https://www.niddk.nih.gov/health.

The main function (egfr) automatically selects the best method for eGFR calculation based on the following metrics:

* If age_y < 18, use the Bedside Schwartz equation. * If age_y >= 18: * Estimate eGFR by the MDRD and CKD-EPI methods * If eGFR,MDRD is estimated < 60 mL/min/1.73 m^2 and eGFR,CKD-EPI < 60, return eGFR,MDRD. * If eGFR,MDRD is estimated >= 60 mL/min/1.73 m^2 and eGFR,CKD-EPI >= 60, return eGFR,CKD-EPI. * Otherwise, return the average of eGFR,MDRD and eGFR,CKD-EPI.

If an IDMS - calibrated assay is used (idms_assay = TRUE), the MDRD equation will be corrected for the assay by approximately 6 equation is only validated for use with IDMS - calibrated assays, and the Cockcroft - Gault is not calibrated for use with an IDMS - calibrated assay. Most labs follow the National Kidney Disease Education Program (NKDEP) recommendation to use an IDMS - calibrated assay, so by default idms_assay = TRUE.

References

Levey AS, Stevens LA, Schmid CH, Zhang YL, Castro AF, 3rd, Feldman HI, et al. A new equation to estimate glomerular filtration rate. Ann Intern Med. 2009;150(9):604-12.

Levey AS, Coresh J, Greene T, Stevens LA, Zhang YL, Hendriksen S, Kusek JW, Van Lente F; Chronic Kidney Disease Epidemiology Collaboration. Using standardized serum creatinine values in the modification of diet in renal disease study equation for estimating glomerular filtration rate. Ann Intern Med. 2006 Aug 15;145(4):247-54.

Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron. 1976;16(1):31-41.

https://www.niddk.nih.gov/health