meal_metrics: Calculate Meal Metrics

In irinagain/iglu: Interpreting Glucose Data from Continuous Glucose Monitors

Calculate Meal Metrics

Description

The function meal_metrics calculates three simple glucose meal metrics

Usage

meal_metrics(data, mealtimes, before_win = 1, after_win = 3,
recovery_win = 1, interpolate = TRUE, adjust_mealtimes = TRUE, dt0 = NULL,
inter_gap = 45, tz = "")

Arguments

data	DataFrame object with column names "id", "time", and "gl". Should only be data for 1 subject. In case multiple subject ids are detected, a warning is produced and only 1st subject is used.
mealtimes	Either a vector of mealtimes, corresponding to data being from a single subject, OR a dataframe with at least 2 columns labeled id and mealtime. Optionally the mealtimes dataframe can include a column labeled meal, giving the meal type (helps to compensate for overlapping meals)
before_win	integer specifying number of hours to extend window before meal
after_win	integer specifying number of hours to extend window after meal
recovery_win	interger specifying number of hours for recovery beyond after window
interpolate	Boolean to indicate if CGM data should be interpolated or not. Default set to FALSE due to time intensive nature of interpolation. Parameters dt0, inter_gap, and tz will only be used if interpolate is set to TRUE.
adjust_mealtimes	Boolean to indicate if function should attempt to align mealtimes with CGM data times. This is important if mealtimes and CGM data times are not exactly aligned, because the function will return NA's for mealtimes that don't match with a corresponding CGM time stamp.
dt0	The time frequency for interpolation in minutes, the default will match the CGM meter's frequency (e.g. 5 min for Dexcom).
inter_gap	The maximum allowable gap (in minutes) for interpolation. The values will not be interpolated between the glucose measurements that are more than inter_gap minutes apart. The default value is 45 min.
tz	A character string specifying the time zone to be used. System-specific (see as.POSIXct), but " " is the current time zone, and "GMT" is UTC (Universal Time, Coordinated). Invalid values are most commonly treated as UTC, on some platforms with a warning.

Details

A tibble object is returned with three metrics calculated for each mealtime. The last three columns of the output correspond to the three metrics: deltag refers to \Delta G, deltat is \Delta T, and basereco is % Baseline recovery. If no meal column is given in the original data, one will be automatically generated with a unique number for each meal.

Value

A tibble object with 6 columns will be returned: id, time, meal, deltag, deltat, and basereco.

References

Service, F. John. (2013) Glucose Variability, Diabetes 62(5): 1398-1404, \Sexpr[results=rd]{tools:::Rd_expr_doi("10.2337/db12-1396")}

Examples

data(example_data_hall)
data(example_meals_hall)
meal_metrics(example_data_hall, example_meals_hall)
meal_metrics(example_data_hall, example_meals_hall)

irinagain/iglu documentation built on April 15, 2024, 4:20 p.m.