Plot histogram of Rate of Change values (ROC)

The function hist_roc produces a histogram plot of ROC values

Usage

hist_roc(data, subjects = NULL, timelag = 15, dt0 = NULL, inter_gap = 45, tz = "")

Arguments

data: DataFrame object with column names "id", "time", and "gl".
subjects: String or list of strings corresponding to subject names in 'id' column of data. Default is all subjects.
timelag: Integer indicating the time period (# minutes) over which rate of change is calculated. Default is 15, e.g. rate of change is the change in glucose over the past 15 minutes divided by 15.
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.

Value

A histogram of ROC values per subject

Details

For the default, a histogram is produced for each subject displaying the ROC values colored by ROC categories defined as follows. The breaks for the categories are: c(-Inf, -3, -2, -1, 1, 2, 3, Inf) where the glucose is in mg/dl and the ROC values are in mg/dl/min. A ROC of -5 mg/dl/min will thus be placed in the first category and colored accordingly.

References

Clarke et al. (2009) Statistical Tools to Analyze Continuous Glucose Monitor Data, Diabetes Diabetes Technology and Therapeutics 11 S45-S54, doi:10.1089/dia.2008.0138 .

Author

Elizabeth Chun, David Buchanan

Examples


data(example_data_1_subject)
hist_roc(example_data_1_subject)


data(example_data_5_subject)
hist_roc(example_data_5_subject)

hist_roc(example_data_5_subject, subjects = 'Subject 3')