CKD-EPI 2021 cystatin C eGFR (race-free)

Estimates GFR from serum cystatin C using the race-free CKD-EPI 2021 cystatin C equation (Inker et al., 2021). The identical formula was first published in 2012; see egfr_ckdepi_cys_2012().

Usage

egfr_ckdepi_cys_2021(
  cystatin,
  age,
  sex,
  label_sex_male = "male",
  label_sex_female = "female"
)

Arguments

cystatin

Numeric vector of serum cystatin C in mg/L.

age

Numeric vector of age in years.

sex

Vector of sex labels (see label_sex_male/label_sex_female).

label_sex_male, label_sex_female

Values in sex that denote male and female records. Defaults to "male"/"female".

Value

Numeric vector of eGFR in mL/min/1.73m^2.

Age coefficient

This function uses an age factor of 0.9962^age, as reported in Table 2 of Inker et al. (2021), which gives the fitted coefficient to four decimal places (95% CI 0.9957 to 0.9966). The original 2012 publication and the National Kidney Foundation calculator print the same coefficient rounded to 0.996. The four-decimal form is used here for consistency with the 0.9938 and 0.9961 factors of the other CKD-EPI 2021 equations. Results are therefore about 1.2% higher at age 60 and 1.6% higher at age 80 than a calculator using 0.996.

References

Inker LA, Eneanya ND, Coresh J, et al. N Engl J Med. 2021;385(19):1737-1749. doi:10.1056/NEJMoa2102953

Examples

egfr_ckdepi_cys_2021(cystatin = 0.9, age = 55, sex = "male")
#> [1] 92.25303