The function conga produces CONGA values a tibble object for any n hours apart.
Arguments
- data
DataFrame object with column names "id", "time", and "gl".
- n
An integer specifying how many hours prior to an observation should be used in the CONGA calculation. The default value is set to n = 24 hours
- 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 with 1 row for each subject, a column for subject id and a column for the CONGA values is returned.
Missing values will be linearly interpolated when close enough to non-missing values.
CONGA is the standard deviation of the difference between glucose values that are exactly n hours apart. CONGA is computed by taking the standard deviation of differences in measurements separated by n hours.
References
McDonnell et al. (2005) : A novel approach to continuous glucose analysis utilizing glycemic variation Diabetes Technology and Therapeutics 7 .253-263, doi:10.1089/dia.2005.7.253 .
Examples
data(example_data_1_subject)
conga(example_data_1_subject)
#> # A tibble: 1 × 2
#> id CONGA
#> <fct> <dbl>
#> 1 Subject 1 37.0
data(example_data_5_subject)
conga(example_data_5_subject)
#> # A tibble: 5 × 2
#> id CONGA
#> <fct> <dbl>
#> 1 Subject 1 37.0
#> 2 Subject 2 60.6
#> 3 Subject 3 63.4
#> 4 Subject 4 33.5
#> 5 Subject 5 73.8