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IsletCalc

IsletCalc computes surrogate indices of pancreatic islet hormone release from fasting and 75 g oral glucose tolerance test (OGTT) measurements. It covers both beta-cell (insulin) and alpha-cell (glucagon) function in one lightweight, dependency-free package.

📖 Full documentation, formulas and interpretation: https://sufyansuleman.github.io/IsletCalc/ (insulin release · glucagon & the liver-alpha-cell axis).

Installation

# development version:
# install.packages("remotes")
remotes::install_github("sufyansuleman/IsletCalc")

Functions

Function	Cell	Indices
`insulin_release()`	beta	HOMA-beta, CIR, Stumvoll, insulinogenic (Xinsdg30, Xinsg30), BIGTT-AIR, disposition (Di, Dibig)
`glucagon_release()`	alpha	fasting glucagon, glucagon AUC
`glucagon_resistance()`	alpha	glucagon suppression ratio, fasting glucagon:insulin ratio

Beta-cell formulas follow Madsen et al. (2024, Nature Metabolism, doi:10.1038/s42255-024-01140-6).

Example

library(IsletCalc)
data(example_data)

# beta-cell insulin release
res <- insulin_release(example_data, category = c("fasting", "ogtt"))
head(res[, c("Homa_beta", "Cir", "Bigtt_air", "Di")], 3)
#>   Homa_beta       Cir Bigtt_air         Di
#> 1  85.08489 0.3862442  1161.789 0.04323715
#> 2  84.84603 0.2054480  1650.537 0.04498467
#> 3 267.63761 0.8485002  3477.854 0.04893109

# alpha-cell glucagon release and resistance
res <- glucagon_release(example_data)
res <- glucagon_resistance(res)
head(res[, c("Fasting_glucagon", "Glucagon_auc",
             "Glucagon_suppression_ratio")], 3)
#>   Fasting_glucagon Glucagon_auc Glucagon_suppression_ratio
#> 1             3.33       372.15                  1.1171171
#> 2            13.71      1123.05                  0.5047411
#> 3             6.28       556.50                  0.7292994

A Glucagon_suppression_ratio at or above 1 indicates a failure to suppress glucagon after the glucose load, a hallmark of hepatic glucagon resistance.

Input data

Column	Meaning	Unit
`G0`, `G30`, `G120`	Glucose at 0/30/120 min	mmol/L
`I0`, `I30`, `I120`	Insulin at 0/30/120 min	pmol/L
`sex`	Male indicator	1 = male, else female
`bmi`	Body mass index	kg/m^2
`Glucagon0`, `Glucagon30`, `Glucagon120`	Glucagon at 0/30/120 min	pmol/L

Only the columns required for a requested index need be present; a missing column skips that index with a warning rather than failing the whole call.

Citation

citation("IsletCalc")

For insulin sensitivity indices (as opposed to release), see InsuSensCalc.