calculate_isi_ogis: OGTT Insulin Sensitivity Index Calculation (OGIS; from...

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OGTT Insulin Sensitivity Index Calculation (OGIS; from standard 75g OGTT)

Description

This function calculates the OGIS index using glucose and insulin sampled during a standard 75g oral glucose tolerance test.

Usage

calculate_isi_ogis(
  time,
  glucose,
  insulin,
  height,
  weight,
  time_units = "min",
  height_units = "m",
  weight_units = "kg",
  glucose_units = "mg/dl",
  insulin_units = "uU/ml"
)

calculate_isi_ogis_180(
  time,
  glucose,
  insulin,
  height,
  weight,
  time_units = "min",
  height_units = "m",
  weight_units = "kg",
  glucose_units = "mg/dl",
  insulin_units = "uU/ml"
)

Arguments

time	a vector indicating time values (in minutes)
glucose	a vecto storing glucose values (in mg/dL)
insulin	a vector storing insulin values (in uU/mL)
height	height, in meters (or )
weight	weight, in kg
time_units	if units are not in "min", can indicate here for unit conversion (options "min" or "hr")
height_units	if units are not in "m", can indicate here for unit conversion (options "m" or "cm")
weight_units	if units are not in "kg", can indicate here for unit conversion (options "kg" or "lbs")
glucose_units	if units are not in "mg/dl", can indicate here for unit conversion (options "mg/dl" or "mmol/l")
insulin_units	if units are not in "uU/ml", can indicate here for unit conversion (options "uU/ml" or "pmol/l")

Details

OGIS requires measurements at 0, 90, and 120 minutes. Alternatively the 3hr version 'calculate_isi_ogis_180()' requires valuse at 0, 120, and 180 minutes. can be used. Note: insulin unit conversion may differ differ depending on assay. Insulin (pmol/l) = insulin (uU/ml)*6 Results are adjusted for BSA OGIS is described in Mari et al.. An Online calculator is available here.

'calculate_isi_ogis()' accepts vectors for time, glucose, insulin, height, and weight.

Value

OGIS Index as a single value (ml\cdot min^{-1} \cdot m^2)

Examples

# individual objects for each item
library(tabletools)
time = c(0,90,120)
glucose = c(90, 135, 115)
insulin = c(15, 150, 0)
calculate_isi_ogis(time = time,  # 344.5
               glucose = glucose,
               insulin = insulin,
               height=170, height_units = "cm",
               weight = 70, weight_units = "kg")
calculate_isi_ogis(time, glucose, insulin, height=1.70, weight = 70)
calculate_isi_ogis(time, glucose, insulin,
               height=70, height_units = "in",
               weight = 154, weight_units = "lbs")

time = c(0,1.5,2)
glucose = c(5.0, 7.5, 6.39)
insulin = c(90, 900, 0)
calculate_isi_ogis(time = time, time_units="hrs",  # 345
               glucose = glucose, glucose_units = "mmol/l",
               insulin = insulin, insulin_units = "pmol/l",
               height=170, height_units = "cm",
               weight = 70, weight_units = "kg")


time = c(0,120, 180)
glucose = c(90, 135, 115)
insulin = c(15, 150, 0)
calculate_isi_ogis_180(time = time,  # 344.5
               glucose = glucose,
               insulin = insulin,
               height=170, height_units = "cm",
               weight = 70, weight_units = "kg")

JMLuther/tabletools documentation built on April 14, 2025, 3:09 a.m.