calc_egfr: Calculate eGFR

In InsightRX/clinPK: Clinical Pharmacokinetics Toolkit

Calculate eGFR

Description

Calculate the estimated glomerular filtration rate (an indicator of renal function) based on measured serum creatinine using one of the following approaches:

• Cockcroft-Gault (using weight, ideal body weight, or adjusted body weight)

• C-G spinal cord injury (using correction factor of 0.7, representing median correction point reported in the original publication (parapalegic patients: 0.8; tetrapalegic patients: 0.6))

• Revised Lund-Malmo

• Modification of Diet in Renal Disease study (MDRD; with or without consideration of race, using either the original equation (published 2001) or the equation updated to reflect serum creatinine assay standardization (2006))

• CKD-EPI (with or without consideration of race, or 2021 re-fit without race)

• Schwartz

• Schwartz revised / bedside

• Jelliffe

• Jelliffe for unstable renal function. Note that the 15 P_adj recommended for hemodialysis patients is not included in this implementation.

• Wright equation for eGFR in cancer patients, with creatinine measured using the Jaffe assay.

Equations for estimation of eGFR from Cystatin C concentrations are available from the 'calc_egfr_cystatin()' function.

Usage

calc_egfr(
  method = "cockcroft_gault",
  sex = NULL,
  age = NULL,
  scr = NULL,
  scr_unit = NULL,
  race = "other",
  weight = NULL,
  height = NULL,
  bsa = NULL,
  preterm = FALSE,
  ckd = FALSE,
  times = NULL,
  bsa_method = "dubois",
  relative = NULL,
  unit_out = "mL/min",
  verbose = TRUE,
  min_value = NULL,
  max_value = NULL,
  fail = TRUE,
  ...
)

Arguments

method	eGFR estimation method, choose from 'cockcroft_gault', 'cockcroft_gault_ideal', 'cockcroft_gault_adjusted', 'cockcroft_gault_adaptive', 'mdrd', 'mdrd_ignore_race', 'mdrd_original', 'mdrd_original_ignore_race', 'ckd_epi', 'ckd_epi_ignore_race', 'ckd_epi_as_2021', 'malmo_lund_revised', 'schwartz', 'jelliffe', 'jellife_unstable', 'wright'.
sex	sex
age	age, in years
scr	serum creatinine (mg/dL)
scr_unit,	'mg/dL' or 'micromol/L' (=='umol/L')
race	'black' or 'other', Required for CKD-EPI and MDRD methods for estimating GFR. To use these methods without race, use 'method = "ckd_epi_ignore_race"', 'method = "ckd_epi_as_2021"', 'method = "mdrd_ignore_race"' or 'method = "mdrd_original_ignore_race"'. See Note section below for important considerations when using race as a predictive factor in eGFR.
weight	weight, in 'kg'
height	height, in 'cm', used for converting to/from BSA-normalized units.
bsa	body surface area
preterm	is patient preterm? Used for Schwartz method.
ckd	chronic kidney disease? Used for Schwartz method.
times	vector of sampling times (in days!) for creatinine (only used in Jelliffe equation for unstable patients)
bsa_method	BSA estimation method, see 'calc_bsa()' for details
relative	'TRUE'/'FALSE'. Report eGFR as per 1.73 m2? Requires BSA if re-calculation required. If 'NULL' (=default), will choose value typical for 'method'.
unit_out	'ml/min' (default), 'L/hr', or 'mL/hr'
verbose	verbosity, show guidance and warnings. 'TRUE' by default
min_value	minimum value ('NULL' by default). The cap is applied in the same unit as the 'unit_out'.
max_value	maximum value ('NULL' by default). The cap is applied in the same unit as the 'unit_out'.
fail	invoke 'stop()' if not all covariates available?
...	arguments passed on to 'calc_abw' or 'calc_dosing_weight'

Note

The MDRD and CKD-EPI equations use race as a factor in estimation of GFR. Racism has historically been and continues to be a problem in medicine, with racialized patients experiencing poorer outcomes. Given this context, the use of race in clinical algorithms should be considered carefully (Vyas et al., NEJM (2020)). Provided here are versions of the CKD-EPI and MDRD equations that do not consider the race of the patient. Removing race from GFR estimation may lead to worse outcomes for Black patients in some contexts (Casal et al., The Lancet (2021)). On the other hand, including race in GFR estimation may also prevent Black patients from obtaining procedures like kidney transplants (Zelnick, et al. JAMA Netw Open. (2021)). In 2021, the NKF/ASN Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Diseases published revised versions of the CKD-EPI equations refit on the original data but with race excluded, which may produce less biased estimates (Inker, et al., NEJM (2021)).

References

• Cockcroft-Gault: Cockcroft & Gault, Nephron (1976)

• Cockcroft-Gault for spinal cord injury: Mirahmadi et al., Paraplegia (1983)

• Revised Lund-Malmo: Nyman et al., Clinical Chemistry and Laboratory Medicine (2014)

• MDRD: Manjunath et al., Curr. Opin. Nephrol. Hypertens. (2001) and Levey et al., Clinical Chemistry (2007). (See Note.)

• CKD-EPI: Levey et al., Annals of Internal Medicine (2009). (See Note.)

• CKD-EPI (2021): Inker, et al., NEJM (2021).

• Schwartz: Schwartz et al., Pediatrics (1976)

• Schwartz revised / bedside: Schwartz et al., Journal of the American Society of Nephrology (2009)

• Jelliffe: Jelliffe, Annals of Internal Medicine (1973)

• Jelliffe for unstable renal function: Jelliffe, American Journal of Nephrology (2002)

• Wright: Wright et al., British Journal of Cancer (2001)

Examples

calc_egfr(sex = "male", age = 50, scr = 1.1, weight = 70)
calc_egfr(sex = "male", age = 50, scr = 1.1, weight = 70, unit_out = "L/hr")
calc_egfr(sex = "male", age = 50, scr = 1.1, weight = 70, bsa = 1.8, method = "ckd_epi")
calc_egfr(sex = "male", age = 50, scr = c(1.1, 0.8),
  weight = 70, height = 170, method = "jelliffe")
calc_egfr(sex = "male", age = 50, scr = c(1.1, 0.8),
  weight = 70, height = 170, method = "jelliffe_unstable")
calc_egfr(sex = "male", age = 50, scr = 1.1,
  weight = 70, bsa = 1.6, method = "malmo_lund_revised", relative = FALSE)

InsightRX/clinPK documentation built on Feb. 28, 2024, 12:06 a.m.