Type: Package
Title: Deficit Index (DI)
Version: 1.1.4
Date: 2018-04-11
Maintainer: Ilya Y. Zhbannikov <ilya.zhbannikov@duke.edu>
Description: A set of utilities for calculating the Deficit (frailty) Index (DI) in gerontological studies. The deficit index was first proposed by Arnold Mitnitski and Kenneth Rockwood and represents a proxy measure of aging and also can be served as a sensitive predictor of survival. For more information, see (i)"Accumulation of Deficits as a Proxy Measure of Aging" by Arnold B. Mitnitski et al. (2001), The Scientific World Journal 1, <doi:10.1100/tsw.2001.58>; (ii) "Frailty, fitness and late-life mortality in relation to chronological and biological age" by Arnold B Mitnitski et al. (2001), BMC Geriatrics2002 2(1), <doi:10.1186/1471-2318-2-1>.
RoxygenNote: 6.0.1
Suggests: knitr, rmarkdown
VignetteBuilder: knitr
Imports: scales
Depends: R (≥ 3.3)
Encoding: UTF-8
License: GPL-3
NeedsCompilation: no
Packaged: 2018-04-11 05:16:39 UTC; ilya
Author: Ilya Y. Zhbannikov [aut, cre]
Repository: CRAN
Date/Publication: 2018-04-11 05:24:20 UTC

This function calculates the Deficit Index (DI) and returns results as list: di a column-vector containing deficit indexes for each individual and columns that were used to calculate the di.

Description

This function calculates the Deficit Index (DI) and returns results as list: di a column-vector containing deficit indexes for each individual and columns that were used to calculate the di.

Usage

di(dat, cols = NULL, invert = NULL, rescale = TRUE, age = NULL,
  rescale.custom = NULL, rescale.avoid = NULL, bins = 7,
  visible = FALSE)

Arguments

dat

A data frame. Required parameter.

cols

A list of column names. Default: NULL.

invert

A list of columns which have to be inverted. Default: NULL.

rescale

A flag that tell the program to rescale columns if the values a not 0/1. Default: TRUE.

age

A name of column which represents age of a patient. Default: NULL.

rescale.custom

A custom rescaling. See example below. Default: NULL.

rescale.avoid

A set of column names for which rescaling should be avoided. Default: NULL.

bins

A number of bins for plotting the DI against age from a dataset. Default: 7.

visible

A flag to show DI plot (mean DI in a population by age) Default: FALSE

Value

A list of two: di a column-vector containing deficit indexes for each individual and columns (rescaled if flag rescale was set to TRUE) that were used to calculate the di.

Examples

library(di)
dd <- data.frame(subj=seq(1:100), 
                 var1=rbinom(100,1,.5), 
                 var2=rbinom(100,1,.5), 
                 var3=rbinom(100,1,.5))
ddi <- di(dd, c("var1", "var2", "var3"))

# Cusom rescaling
ddi <- di(dd, c("var1", "var2", "var3"), rescale.custom=c("var1:0.1:0.5"))
ddi