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Get started with IsletCalc

library(IsletCalc)

Overview

IsletCalc computes surrogate indices of pancreatic islet hormone release from fasting and 75 g oral glucose tolerance test (OGTT) measurements, covering both beta-cell and alpha-cell function:

Insulin release

data(example_data)
res <- insulin_release(example_data, category = c("fasting", "ogtt"))
head(res)
#>     G0  G30 G120   I0   I30  I120 sex  bmi Glucagon0 Glucagon30 Glucagon120
#> 1 5.71 8.39 5.59 56.4 283.5 171.5   0 19.3      3.33       2.58        3.72
#> 2 5.06 8.45 6.31 39.7 153.9 115.1   0 29.4     13.71      10.10        6.92
#> 3 4.59 7.85 6.16 87.5 512.8 257.1   0 26.6      6.28       4.27        4.58
#> 4 5.29 7.72 7.01 71.7 390.1  67.7   1 21.4     11.36       8.71        8.77
#> 5 5.13 8.27 5.78 31.3 182.5  90.7   0 31.0     11.98       8.02        9.56
#> 6 5.20 9.56 5.12 52.9 374.3 155.3   1 27.7      9.40       7.17        9.05
#>   Homa_beta       Cir  Stumvoll  Xinsdg30  Xinsg30         Di Bigtt_air
#> 1  85.08489 0.3862442  850.5693 0.7847755 4.512225 0.04323715  1161.789
#> 2  84.84603 0.2054480  542.2165 0.3119820 2.252916 0.04498467  1650.537
#> 3 267.63761 0.8485002 1462.1662 1.2082057 9.031530 0.04893109  3477.854
#> 4 133.54626 0.6786166 1196.1813 1.2134723 6.875295 0.05766393  2609.218
#> 5  64.02098 0.2591574  587.8071 0.4459490 3.047768 0.07130919  1734.967
#> 6 103.74624 0.3552093  841.1615 0.6826883 5.604328 0.05052567  2111.044
#>      Dibig
#> 1 13100.08
#> 2 16881.84
#> 3 24216.89
#> 4 24179.56
#> 5 17734.61
#> 6 16087.13

Request a single category if you only have fasting values:

head(insulin_release(example_data, category = "fasting"))
#>     G0  G30 G120   I0   I30  I120 sex  bmi Glucagon0 Glucagon30 Glucagon120
#> 1 5.71 8.39 5.59 56.4 283.5 171.5   0 19.3      3.33       2.58        3.72
#> 2 5.06 8.45 6.31 39.7 153.9 115.1   0 29.4     13.71      10.10        6.92
#> 3 4.59 7.85 6.16 87.5 512.8 257.1   0 26.6      6.28       4.27        4.58
#> 4 5.29 7.72 7.01 71.7 390.1  67.7   1 21.4     11.36       8.71        8.77
#> 5 5.13 8.27 5.78 31.3 182.5  90.7   0 31.0     11.98       8.02        9.56
#> 6 5.20 9.56 5.12 52.9 374.3 155.3   1 27.7      9.40       7.17        9.05
#>   Homa_beta
#> 1  85.08489
#> 2  84.84603
#> 3 267.63761
#> 4 133.54626
#> 5  64.02098
#> 6 103.74624

Glucagon release

head(glucagon_release(example_data))
#>     G0  G30 G120   I0   I30  I120 sex  bmi Glucagon0 Glucagon30 Glucagon120
#> 1 5.71 8.39 5.59 56.4 283.5 171.5   0 19.3      3.33       2.58        3.72
#> 2 5.06 8.45 6.31 39.7 153.9 115.1   0 29.4     13.71      10.10        6.92
#> 3 4.59 7.85 6.16 87.5 512.8 257.1   0 26.6      6.28       4.27        4.58
#> 4 5.29 7.72 7.01 71.7 390.1  67.7   1 21.4     11.36       8.71        8.77
#> 5 5.13 8.27 5.78 31.3 182.5  90.7   0 31.0     11.98       8.02        9.56
#> 6 5.20 9.56 5.12 52.9 374.3 155.3   1 27.7      9.40       7.17        9.05
#>   Fasting_glucagon Glucagon_auc
#> 1             3.33       372.15
#> 2            13.71      1123.05
#> 3             6.28       556.50
#> 4            11.36      1087.65
#> 5            11.98      1091.10
#> 6             9.40       978.45

Glucagon resistance

head(glucagon_resistance(example_data))
#>     G0  G30 G120   I0   I30  I120 sex  bmi Glucagon0 Glucagon30 Glucagon120
#> 1 5.71 8.39 5.59 56.4 283.5 171.5   0 19.3      3.33       2.58        3.72
#> 2 5.06 8.45 6.31 39.7 153.9 115.1   0 29.4     13.71      10.10        6.92
#> 3 4.59 7.85 6.16 87.5 512.8 257.1   0 26.6      6.28       4.27        4.58
#> 4 5.29 7.72 7.01 71.7 390.1  67.7   1 21.4     11.36       8.71        8.77
#> 5 5.13 8.27 5.78 31.3 182.5  90.7   0 31.0     11.98       8.02        9.56
#> 6 5.20 9.56 5.12 52.9 374.3 155.3   1 27.7      9.40       7.17        9.05
#>   Glucagon_suppression_ratio Glucagon_insulin_ratio
#> 1                  1.1171171             0.05904255
#> 2                  0.5047411             0.34534005
#> 3                  0.7292994             0.07177143
#> 4                  0.7720070             0.15843794
#> 5                  0.7979967             0.38274760
#> 6                  0.9627660             0.17769376

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

All three functions expect a data frame with a subset of these columns:

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, otherwise female
bmi Body mass index kg/m^2
Glucagon0, Glucagon30, Glucagon120 Glucagon at 0/30/120 min pmol/L

If a column required for a given index is missing, that index is skipped with a warning rather than the whole function failing, so you can still compute whichever indices your data supports.

Further reading

This vignette is a quick start. The package website hosts fuller articles with the exact formulas, unit conventions, biological interpretation and references:

These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.
Health stats visible at Monitor.