raw_JRS {rspiro}

Convert z-scores back to raw spirometric values using JRS (2014) equations

Description

This function takes z-scores based on the JRS (Japanese Respiratory Society 2014) equations, plus demographic data (age, height and gender), and converts them back into absolute spirometry measurements (FEV1, FVC, VC, or FEV1FVC) in lt.

Usage

raw_JRS(
  age,
  height,
  gender = 1,
  FEV1 = NULL,
  FVC = NULL,
  VC = NULL,
  FEV1FVC = 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.

FEV1

Forced Expiratory Volume in 1 second (z-score)

FVC

Forced Vital Capacity (z-score)

VC

Vital Capacity (z-score)

FEV1FVC

FEV1 / 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 and gender 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_JRS(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))