iglu (version 4.2.2)

gri: Calculate Glycemia Risk Index (GRI)

Description

The function gri produces a tibble object with values equal to the glycemia risk index (GRI) metric. The output columns are subject id and GRI value. ' The output rows correspond to subjects.

Usage

gri(data, tz = "")

Value

A tibble object with columns for subject id and GRI value. Rows correspond to individual subjects.

Arguments

data

DataFrame object with column names "id", "time", and "gl", or numeric vector of glucose values.

tz

Default: "". 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.

Author

Elizabeth Chun

Details

A tibble object with 1 row for each subject, a column for subject id and column for GRI is returned. The formula for GRI is as follows:

\((3.0 × VLow) + (2.4 × Low) + (1.6 × VHigh) + (0.8 × High)\)

where VLow, Low, VHigh, and High correspond to the percent of glucose values in the ranges <54 mg/dL, 54-70 mg/dL, >250 mg/dL, and 180-250 mg/dL respectively. The maximum allowed value for GRI is 100%, any calculated values higher than 100 are capped.

References

Klonoff et al. (2022) A Glycemia Risk Index (GRI) of Hypoglycemia and Hyperglycemia for Continuous Glucose Monitoring Validated by Clinician Ratings. J Diabetes Sci Technol tools:::Rd_expr_doi("10.1177/19322968221085273").

Examples

data(example_data_1_subject)
gri(example_data_1_subject)

data(example_data_5_subject)
gri(example_data_5_subject, tz = 'GMT')