raw_GLI {rspiro}

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
)

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.

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.

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))