An R package that implements the methods to derive disease-specific hazard ratios (dsHR) from overall hazard ratios (oHR) described in the publication:
- Alarid-Escudero F, Kuntz KM โPotential bias associated with modeling the effectiveness of healthcare interventions in reducing mortality using an overall hazard ratio.โ PharmacoEcon 2020; 38(3):285-296. https://doi.org/10.1007/s40273-019-00859-5
You can install the development version from GitHub with:
# install.packages("devtools")
devtools::install_github("feralaes/dshr")
This is a basic example which shows you how to derive a disease-specific hazard ratio (dsHR) from a disease-specific mortality rate, an overall hazard ratio (oHR) reported in a trial, the initial age of the cohort in the trial, and the length of the trial using an empirical approach with background mortality from US life tables.
library(dshr)
ohr <- 0.55 # Overall hazard ratio (oHR)
n_age_init <- 50 # Initial age of cohort in trial
trial_time <- 5 # Length of clinial trial in years
mu_Dis <- 0.05 # Disease-specific mortality rate
dshr_emp <- calc_dshr_from_ohr(ohr = ohr,
mu_Dis = mu_Dis,
n_age_init = n_age_init,
trial_time = trial_time,
hazard = "empirical")
dshr_emp
#> dshr
#> 0.5038836
To estimate dsHR assuming an anlaytical functional form of background
mortality (either exponential, linear or geometric), estimate the mu0
and alpha
parameters of the functional form, type them in
calc_dshr_from_ohr
and substitute empirical
with the functional form
of interest. For example, using an exponential functional form with
background mortality from US life tables, the estimated parameters are
coef_hazard_exp <- est_hazard_params(n_age_init = n_age_init,
trial_time = trial_time,
hazard = "exponential")
coef_hazard_exp
#> $mu0
#> (Intercept)
#> 0.0001105985
#>
#> $alpha
#> Age
#> 0.07362561
and the dshr is
dshr_exp <- calc_dshr_from_ohr(ohr = ohr,
mu_Dis = mu_Dis,
n_age_init = n_age_init,
trial_time = trial_time,
mu0 = coef_hazard_exp$mu0,
alpha = coef_hazard_exp$alpha,
hazard = "exponential")
dshr_exp
#> dshr
#> 0.5022318