R/hazard_ratio_to_le.R

In gompertztrunc: Conducting Maximum Likelihood Estimation with Truncated Mortality Data

#' Translate a single hazard ratio to remaining life expectancy
#'
#' Translate a single hazard ratio to effect on remaining life
#' expectancy at a specified age, using a Gompertz mortality schedule
#' as the baseline
#'
#' @param lower age at which to compute change in remaining life expectancy
#' @param upper upper age bound for life table calculations
#' @param hr hazard ratio
#' @param M Gompertz modal age at death parameter
#' @param b Gompertz mortality slope parameter
#'
#' @return hazard ratio converted to effect on life expectancy
#'
#' @export
#'



hazard_ratio_to_le <- Vectorize(function(lower, upper, hr, M = 80, b = 0.1) {

  ## convert alpha
  my.alpha <- bM2a(M = M, b=b)

  ## numident gradient
  le_estimate <- get.trunc.mean.gomp(my.alpha * hr, b, lower, upper) -
    get.trunc.mean.gomp(my.alpha, b, lower, upper)

  return(le_estimate)
})