Estimates GFR from serum creatinine using the European Kidney Function Consortium (EKFC) creatinine equation (Pottel et al., 2021).
Usage
egfr_ekfc_cr(
creatinine,
age,
sex,
creatinine_units = "mg/dl",
label_sex_male = "male",
label_sex_female = "female",
q = NULL
)Arguments
- creatinine
Numeric vector of serum creatinine.
- age
Numeric vector of age in years.
- sex
Vector of sex labels (see
label_sex_male/label_sex_female).- creatinine_units
Units of
creatinine:"mg/dl"(default) or"umol/l".- label_sex_male, label_sex_female
Values in
sexthat denote male and female records. Defaults to"male"/"female".- q
Optional numeric vector of the reference creatinine Q value (median creatinine for the age/sex, in mg/dL). When
NULL(the default) the built-in EKFC reference Q is used; supply a value to use a population-, assay-, or individual-specific Q. Recycled to the length of the other inputs.
Reference Q
The default Q follows the published EKFC specification. For ages 2-25 years inclusive Q is a sex-specific polynomial in age (given by the authors on the micromol/L scale and converted here to mg/dL):
$$\ln(Q_{male}) = 3.200 + 0.259 a - 0.543 \ln(a) - 0.00763 a^2 + 0.0000790 a^3$$ $$\ln(Q_{female}) = 3.080 + 0.177 a - 0.223 \ln(a) - 0.00596 a^2 + 0.0000686 a^3$$
Above age 25 Q is constant at the adult values of 0.90 mg/dL (80 micromol/L) for males and 0.70 mg/dL (62 micromol/L) for females. The polynomial and the adult plateau differ by roughly 1% at the age-25 knot; this step is part of the published specification and is preserved deliberately.
Population-specific adult Q values (e.g. 1.02 / 0.74 mg/dL for Black
Europeans) may be supplied via q.
Validity
Developed and validated across ages 2-90 years and serum creatinine 40-490 micromol/L (0.45-5.54 mg/dL). Values outside this range are extrapolations.
References
Pottel H, Bjork J, Courbebaisse M, et al. Development and validation of a modified full age spectrum creatinine-based equation to estimate glomerular filtration rate. Ann Intern Med. 2021;174(2):183-191. doi:10.7326/M20-4366