Calculate eGFR based on creatinine and cystatin C measurements

Calculate the estimated glomerular filtration rate based on both measured serum creatinine and serum cystatin C using one of the following approaches:

• CKD-EPI creatinine-cystatin C (2021 re-fit without race). Developed in adults (>= 18 years) only.

• European Kidney Function Consortium (EKFC): the arithmetic mean of the creatinine-based and cystatin C-based EKFC equations. The cystatin C-based equation was validated in adults (>= 18 years) only.

Usage

calc_egfr_combined(
  method = c("ckd_epi_as_2021", "ekfc"),
  sex = NULL,
  age = NULL,
  scr = NULL,
  scr_unit = NULL,
  cystatin = NULL,
  cystatin_unit = "mg/L",
  weight = NULL,
  height = NULL,
  bsa = NULL,
  bsa_method = "dubois",
  relative = TRUE,
  unit_out = "mL/min",
  verbose = TRUE,
  min_value = NULL,
  max_value = NULL,
  fail = TRUE
)

Arguments

method

eGFR estimation method, choose from "ckd_epi_as_2021", "ekfc".

sex

sex

age

age, in years

scr

serum creatinine (mg/dL)

scr_unit

"mg/dL" or "micromol/L" (=="umol/L")

cystatin

serum cystatin C concentration (mg/L)

cystatin_unit

only "mg/L" available

weight

weight, in kg, used for converting to absolute units.

height

height, in cm, used for converting to absolute units.

bsa

body surface area, used for converting to absolute units.

bsa_method

BSA estimation method, see calc_bsa() for details

relative

TRUE/FALSE. Report eGFR as per 1.73 m2? If FALSE, requires bsa, or weight and height to calculate it.

unit_out

"mL/min" (default), "mL/hr", "L/min", or "L/hr" (case-insensitive)

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?

References

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

• EKFC: Pottel et al., NEJM (2023)

See also

• calc_egfr() for equations using creatinine alone

• calc_egfr_cystatin() for equations using cystatin C alone

Examples

calc_egfr_combined(sex = "female", age = 50, scr = 0.9, cystatin = 1.1)
#> Creatinine unit not specified, assuming mg/dL.
#> $value
#> [1] 72.80027
#> 
#> $age
#> [1] 50
#> 
#> $bsa
#> NULL
#> 
#> $sex
#> [1] "female"
#> 
#> $scr
#> [1] 0.9
#> 
#> $cystatin
#> [1] 1.1
#> 
#> $unit
#> [1] "ml/min/1.73m^2"
#> 
#> $capped
#> list()
#> 
calc_egfr_combined(sex = "female", age = 50, scr = 0.9, cystatin = 1.1,
  method = "ekfc")
#> Creatinine unit not specified, assuming mg/dL.
#> $value
#> [1] 71.8612
#> 
#> $age
#> [1] 50
#> 
#> $bsa
#> NULL
#> 
#> $sex
#> [1] "female"
#> 
#> $scr
#> [1] 0.9
#> 
#> $cystatin
#> [1] 1.1
#> 
#> $unit
#> [1] "ml/min/1.73m^2"
#> 
#> $capped
#> list()
#> 
calc_egfr_combined(sex = "female", age = 50, scr = 0.9, cystatin = 1.1,
  weight = 70, height = 165, relative = FALSE, unit_out = "L/hr")
#> Creatinine unit not specified, assuming mg/dL.
#> $value
#> [1] 4.471435
#> 
#> $age
#> [1] 50
#> 
#> $bsa
#> [1] 1.77096
#> 
#> $sex
#> [1] "female"
#> 
#> $scr
#> [1] 0.9
#> 
#> $cystatin
#> [1] 1.1
#> 
#> $unit
#> [1] "l/hr"
#> 
#> $capped
#> list()
#>