insulin.secretion: Insulin Secretion Rate Deconvolution

Description

Calculates insulin secretion rates from C-peptide values based on the methods described in Van Cauter et al. (1992) doi:10.2337/diab.41.3.368. Includes functions to calculate estimated insulin secretion rates using linear or cubic spline interpolation of c-peptide values (see Eaton et al., 1980 doi:10.1210/jcem-51-3-520 and Polonsky et al., 1986 doi:10.1172/JCI112308) and to calculate estimates of input coefficients (volume of distribution, short half life, long half life, and fraction attributed to short half life) as described by Van Cauter. Although the generated coefficients are specific to insulin secretion, the two-compartment secretion model used here is useful for certain applications beyond insulin.

Author(s)

Maintainer: Ken Stier kennethstier99@gmail.com [copyright holder]

See Also

Useful links:

• https://github.com/kstier/isr.deconv

• Report bugs at https://github.com/kstier/isr.deconv/issues

Insulin Secretion Rate Deconvolution

Description

Estimates insulin secretion rate based on a time series of c-peptide values based on the Van Cauter method. C-peptide values are interpolated using either linear approximation or a cubic spline; the linear method (default) will output a time series of insulin secretory rates at time points between each input time, whereas the spline method will output a function which can be called to return insulin secretory rates for specific time points.

Typically, c-peptide values are provided in pmol/mL and time is in minutes, resulting in insulin secretion rate outputs in pmol/min.

Although this function was designed with insulin secretion in mind, it uses a two-compartment secretion model that may be applied beyond insulin.

Usage

isr.deconv(
  timeseries,
  cpepseries,
  vol,
  shl,
  lhl,
  frc,
  method = c("linear", "spline"),
  plotspline = FALSE,
  plotisr = FALSE,
  isr.validated.vals,
  isr.validated.time
)

Arguments

Value

If method = "linear" is selected (default), returns a list of time points and insulin secretory rates. If method = "spline" is selected, returns a function which can be called to return insulin secretory rates at specified time points.

See Also

isr.volume(), isr.shortHL(), isr.longHL(), isr.fraction()

Examples

isr.deconv(
  timeseries = c(-30, 0, 30, 60, 90, 120),
  cpepseries = c(1.72, 1.72, 5.40, 5.23, 2.71, 1.79),
  vol = 6104,
  shl = 4.55,
  lhl = 31.05,
  frc = 0.78,
  method = "linear",
  plotspline = TRUE,
  plotisr = TRUE,
)

C-Peptide Fraction Attributable to Short Half Life Lookup

Description

Outputs the relevant fraction attributable to short half life for use in isr.deconv() based on patient type (normal, obese, or non-insulin dependent diabetes mellitus).

Usage

isr.fraction(subject.type = c("normal", "obese", "niddm"))

Arguments

Value

Numeric value.

See Also

isr.deconv()

Examples

isr.fraction("normal")

isr.fraction("obese")

isr.fraction("niddm")

C-Peptide Long Half Life Calculator

Description

Outputs the long half life based on patient age for use in isr.deconv() per the Van Cauter method of estimating insulin secretion rate.

Usage

isr.longHL(subject.age)

Arguments

Value

Numeric value.

See Also

isr.deconv()

Examples

isr.longHL(18.08)

C-Peptide Short Half Life Calculator

Description

Outputs the relevant long half life of c-peptide for use in isr.deconv() based on patient type (normal, obese, or non-insulin dependent diabetes mellitus).

Usage

isr.shortHL(subject.type = c("normal", "obese", "niddm"))

Arguments

Value

Numeric value.

See Also

isr.deconv()

Examples

isr.shortHL("normal")

isr.shortHL("obese")

isr.shortHL("niddm")

Serum Volume Calculator

Description

Calculates the estimated serum volume based on patient sex, weight, and height for use in isr.deconv().

Usage

isr.volume(subject.sex = c("m", "f"), subject.weight, subject.height)

Arguments

Value

Numeric value.

See Also

isr.deconv()

Examples

isr.volume("m", 86.2, 181.5)