ADaM BDS for average glucose measurements

Illustrates Domains

LB

Illustrates Variables

LBSPEC
LBANMETH
LBTEST
LBTESTCD

Illustrates Data Structures

BDS


Content

This example illustrates raw glucose levels based on plasma equivalents obtained from a subject's CGM. These values are used in the derivation of analysis endpoints. In this study, the sponsor captured the raw glucose levels for a 2-week baseline period at the start of the study, and a 2-week period at the end of the study. Only example rows of the data are shown below. Glucose values were typically measured every 5 minutes. The sponsor decided not to populate VISITNUM for these data. However, VISITNUM is included in the dataset because it is an expected variable. 

lb.xpt
Rows 1-4:Show the plasma-equivalent glucose values that were obtained from the subject's CGM device about every 5 minutes. Only the first 4 records are shown for the baseline period. SPDEVID is used to indicate the device from which data were obtained. LBMETHOD was represented as "CALCULATION" and LBANMETH was represented as "DEVICE ALGORITHM". The sponsor can provide more details on the algorithm in the Device in Use (DU) domain.
Rows 5-7:Show the plasma-equivalent glucose values that were obtained from the subject's CGM on the last day of the collection period at week 52. Only a few records are shown.

lb.xpt

RowSTUDYIDDOMAINUSUBJIDSPDEVIDLBSEQLBTESTCDLBTESTLBORRESLBORRESULBSTRESCLBSTRESNLBSTRESULBSPECLBMETHODLBANMETHVISITNUMLBDTCLBDY
1TD011LB001-001CGM-0011GLUCPEPlasma Equivalent Glucose118mg/dL118118mg/dLINTERSTITIAL FLUIDCALCULATIONDEVICE ALGORITHM
2016-09-08 T10:09:337
2TD011LB001-001CGM-0012GLUCPEPlasma Equivalent Glucose117mg/dL117117mg/dLINTERSTITIAL FLUIDCALCULATIONDEVICE ALGORITHM
2016-09-08 T10:14:367
3TD011LB001-001CGM-0013GLUCPEPlasma Equivalent Glucose110mg/dL110110mg/dLINTERSTITIAL FLUIDCALCULATIONDEVICE ALGORITHM
2016-09-08 T10:19:367
4TD011LB001-001CGM-0014GLUCPEPlasma Equivalent Glucose90mg/dL9090mg/dLINTERSTITIAL FLUIDCALCULATIONDEVICE ALGORITHM
2016-09-08 T10:24:527
5TD011LB001-001CGM-0014033GLUCPEPlasma Equivalent Glucose107mg/dL107107mg/dLINTERSTITIAL FLUIDCALCULATIONDEVICE ALGORITHM
2017-09-06 T10:09:33369
6TD011LB001-001CGM-0014034GLUCPEPlasma Equivalent Glucose106mg/dL106106mg/dLINTERSTITIAL FLUIDCALCULATIONDEVICE ALGORITHM
2017-09-06 T10:14:20369
7TD011LB001-001CGM-0014035GLUCPEPlasma Equivalent Glucose100mg/dL100100mg/dLINTERSTITIAL FLUIDCALCULATIONDEVICE ALGORITHM
2017-09-06 T10:19:03369

This example uses ADaM BDS to model parameters for average glucose measurements using 3 specific time spans relative to the 2 study timepoints. It is not intended to illustrate every possible variable that might be included in datasets created for statistical analysis of CGM data, nor is it intended to serve as a recommendation for which time spans a sponsor should select when performing CGM base change from baseline analysis.  

The example illustrates how some variables are derived from the glucose values downloaded from CGMs during a study. In this study, the sponsor was interested in comparing the change from the initial 2-week baseline period to the last 2-week post-baseline period at the end of the 52-week study. The 2-week periods are anchored by the LBDTC value chosen to anchor the period. There is an LBDTC value chosen to anchor the baseline period and and an LBDTC value chosen to anchor the week 52 period. This LBDTC value is used to determine the AEENDTM value used to define the analysis interval end; ASTDTM is derived by calculating the interval value described in PARAM prior to AENDTM.

The metadata and derivations presented are for illustrative purposes only. Refer to ADaM v2.1 and Version 1.1 of the ADaM Implementation Guide (ADaMIG) for required background about ADaM and the ADaM data structures.

This is an example ADCGM dataset. It is based on an SDTM LB dataset containing the observations per subject per parameter per visit per assessment. 

adcgm.xpt

adcgm.xpt

Row

STUDYID

USUBJID

SPDEVIDTRT01PPARAMN

PARAMCD

PARAM

AVISITN

AVISIT

AVAL

BASE

CHG

ABLFL

ASTDTM

AENDTM

1TD011001-001

CGM-001

DRUG A1AVGGL24HAverage Glucose (mg/dL) 24 Hours Prior to  the End of the Analysis Interval0Baseline113.7113.7.Y07OCT2016:13:10:3308OCT2016:13:10:33
2TD011001-001CGM-001DRUG A1AVGGL24HAverage Glucose (mg/dL) 24 Hours Prior to  the End of the Analysis Interval52Week 52107.7

113.7

-6.2
07OCT2017:13:15:0008OCT2017:13:1500
3TD011001-001CGM-001DRUG A2AVGGL4HAverage Glucose (mg/dL) 24 to 20 Hours Prior to  the End of the Analysis Interval0Baseline112.5112.5.Y07OCT2016:13:10:33

07OCT2016:17:10:33

4TD011001-001CGM-001DRUG A2AVGGL4HAverage Glucose (mg/dL)  24 to 20 Hours Prior to  the End of the Analysis Interval52Week 52107.8112.5-4.7
07OCT2017:13:15:0007OCT2017:17:15:00
5TD011001-001CGM-001DRUG A3AVGGL2WAverage Glucose (mg/dL) 2 Weeks Prior to  the End of the Analysis Interval0Baseline104.0104.0.Y24SEP2016:13:10:3308OCT2016:13:10:33
6TD011001-001CGM-001DRUG A3AVGGL2WAverage Glucose (mg/dL) 2 Weeks Prior to  the End of the Analysis Interval52Week 52101.6

104.0

-2.4
24SEP2017:13:10:3308OCT2017:13:15:00

The following is an example of the ADCGM metadata for the analysis of the change from baseline for the endpoints defined in the study protocol. A BDS structure was used. The BDS dataset contains 1 or more records per subject, per analysis parameter, per analysis timepoint.

ADCGM Dataset Metadata

ADCGM Variable Metadata

Parameter Value Level List - ADCGM [AVAL]