R/nefa_index.R

In jcpsantiago/IScalc: Calculate Various Glucose Metabolism Indices

#' NEFA insulin index
#'
#' @param ins  An ordered vector of insulin values.
#' @param bmi  Body-mass index.
#' @param nefa An ordered vector of NEFA values.
#'
#' @return A double.
#'
#' @examples
nefa_index <- function(ins, bmi, nefa) {
  if (length(ins) != 3 || length(bmi) != 1 || length(nefa) != 1) {
    stop("Arguments have the wrong length!")
  }

  60 * exp(
    3.853 - 0.9 * log(bmi[1])
      - 0.205 * log(ins[1])
      - 0.128 * log(ins[2])
      - 0.256 * log(ins[3])
      - 0.138 * log(nefa)
  )
}