rspiro (version 0.4)

raw_GLI: Convert z-scores back to raw spirometric values using GLI-2012 equations

Description

This function takes z-scores based on the GLI-2012 equations, plus demographic data (age, height, gender and ethnicity), and converts them back into absolute spirometry measurements (FEV1, FVC, etc) in lt.

Usage

raw_GLI(
  age,
  height,
  gender = 1,
  ethnicity = 1,
  FEV1 = NULL,
  FVC = NULL,
  FEV1FVC = NULL,
  FEF2575 = NULL,
  FEF75 = NULL,
  FEV075 = NULL,
  FEV075FVC = NULL
)

Value

If only one spirometry z-score argument is supplied, the function returns a numeric vector. If more are supplied, the function returns a data.frame with the same number of columns.

Arguments

age

Age in years

height

Height in meters

gender

Gender (1 = male, 2 = female) or a factor with two levels (first = male). Default is 1.

ethnicity

Ethnicity (1 = Caucasian, 2 = African-American, 3 = NE Asian, 4 = SE Asian, 5 = Other/mixed). Default is 1.

FEV1

Forced Expiratory Volume in 1 second (z-score)

FVC

Forced Vital Capacity (z-score)

FEV1FVC

FEV1 / FVC (as z-score)

FEF2575

Forced Expiratory Flow between 25% and 75% of FVC (z-score)

FEF75

Forced Expiratory Flow at 75% of FVC (z-score)

FEV075

Forced Expiratory Volume in 0.75 sec (z-score)

FEV075FVC

FEV0.75 / FVC (as z-score)

Details

At least one of the spirometric z-score arguments must be set (i.e. be non-NULL). Arguments age, height, gender and ethnicity must be vectors of length equal to the length of the z-score vector(s), or of length one, in which case their value is recycled. If any input vector is not of equal length, the function stops with an error.

Examples

# Random data, 4 patients, one z-score parameter supplied (FEV1)
raw_GLI(age=seq(25,40,5), height=c(1.8, 1.9, 1.75, 1.85),
      gender=c(2,1,2,1), FEV1=c(-1.2, -1.9, 0, 0.5))