Trial Outcomes & Findings for Opportunistic Screening for Prediabetes and Early Diabetes in Primary Care (NCT NCT00787839)

Results Overview

Area under ROC curve (AROC) for prediction of diabetes (based on OGTT) and high-risk dysglycemia (based on OGTT, IGT with 2 hour OGTT glucose 140-199 mg/dl, and/or IFG with fasting glucose 110-125 mg/dl). ROC curves are plots of (1-sensitivity) vs. (1-specificity) for all possible screening cutoffs, so a higher AROC indicates higher predictive accuracy. A perfect test would have an AROC of 1.00, while a test equivalent to tossing a coin (random) would have an AROC of 0.50; if confidence limits include 0.50, predictive accuracy is no better than chance. It is important to appreciate that while AROC analysis can show the relative accuracy of different screening tests, and aid the selection of which test to use in clinical practice, such an analysis does not define what the optimal screening test cutoff is. Selection of the optimal cutoff generally requires consideration of other factors, such as costs and/or the clinical importance of having higher or lower sensitivity.

Recruitment status

COMPLETED

Target enrollment

1939 participants

Primary outcome timeframe

3 years

Results posted on

2015-04-27

Participant Flow

Atlanta VA patients without known diabetes, who were at high risk of having unrecognized dysglycemia based on age \>=45 years, BMI \>=25 kg/m2, or other risk factors, were eligible for the study. Patients presenting for primary care visits were approached if they appeared to have age \>=45 years and BMI \>=25 kg/m2.

Participant milestones

Participant milestones
Measure	Group 1 Atlanta VA Medical Center patients who meet criteria for screening for prediabetes and early diabetes based on standard guidelines of the VA, American Diabetes Association, and NIH. This primarily included outpatient Veterans. Subjects were primarily included if they had age at least 45 years and BMI of 25 or greater, but some younger subjects were also included if they had risk factors for diabetes. Glucose challenge test: At a first outpatient visit, at different times of the day and without a prior fast, subjects will have a 50 gram glucose drink followed by measurement of plasma and capillary glucose along with A1c one hour later. They will also fill out questionnaires. At a second outpatient visit, in the morning after fasting overnight, they will have a 75 gram oral glucose tolerance test. Glucose tolerance test: Subjects found to have diabetes or prediabetes on the initial glucose tolerance test may be requested to have a repeat glucose tolerance test and A1c.
Overall Study STARTED	1939
Overall Study Consented	1939
Overall Study Completed GCT Screening	1876
Overall Study Complete GCT, OGTT, A1c, Demographics	1535
Overall Study COMPLETED	1535
Overall Study NOT COMPLETED	404

Reasons for withdrawal

Reasons for withdrawal
Measure	Group 1 Atlanta VA Medical Center patients who meet criteria for screening for prediabetes and early diabetes based on standard guidelines of the VA, American Diabetes Association, and NIH. This primarily included outpatient Veterans. Subjects were primarily included if they had age at least 45 years and BMI of 25 or greater, but some younger subjects were also included if they had risk factors for diabetes. Glucose challenge test: At a first outpatient visit, at different times of the day and without a prior fast, subjects will have a 50 gram glucose drink followed by measurement of plasma and capillary glucose along with A1c one hour later. They will also fill out questionnaires. At a second outpatient visit, in the morning after fasting overnight, they will have a 75 gram oral glucose tolerance test. Glucose tolerance test: Subjects found to have diabetes or prediabetes on the initial glucose tolerance test may be requested to have a repeat glucose tolerance test and A1c.
Overall Study Failure to have the OGTT was most common	404

Baseline Characteristics

Opportunistic Screening for Prediabetes and Early Diabetes in Primary Care

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Group 1 n=1535 Participants Atlanta VA Medical Center patients who meet criteria for screening for prediabetes and early diabetes based on standard guidelines of the VA, American Diabetes Association, and NIH. This primarily included outpatient Veterans. Subjects were primarily included if they had age at least 45 years and BMI of 25 or greater, but some younger subjects were also included if they had risk factors for diabetes.
Age, Continuous	56.1 years STANDARD_DEVIATION 9.93 • n=5 Participants
Sex: Female, Male Female	94 Participants n=5 Participants
Sex: Female, Male Male	1441 Participants n=5 Participants
Region of Enrollment United States	1535 participants n=5 Participants
BMI	30.3 kg/m2 STANDARD_DEVIATION 5.20 • n=5 Participants

PRIMARY outcome

Timeframe: 3 years

Area under ROC curve (AROC) for prediction of diabetes (based on OGTT) and high-risk dysglycemia (based on OGTT, IGT with 2 hour OGTT glucose 140-199 mg/dl, and/or IFG with fasting glucose 110-125 mg/dl). ROC curves are plots of (1-sensitivity) vs. (1-specificity) for all possible screening cutoffs, so a higher AROC indicates higher predictive accuracy. A perfect test would have an AROC of 1.00, while a test equivalent to tossing a coin (random) would have an AROC of 0.50; if confidence limits include 0.50, predictive accuracy is no better than chance. It is important to appreciate that while AROC analysis can show the relative accuracy of different screening tests, and aid the selection of which test to use in clinical practice, such an analysis does not define what the optimal screening test cutoff is. Selection of the optimal cutoff generally requires consideration of other factors, such as costs and/or the clinical importance of having higher or lower sensitivity.

Outcome measures

Outcome measures
Measure	GCTpl - Diabetes n=1535 Participants plasma glucose measured 1 hour after a 50g oral glucose challenge, performed at any time during the day, without requiring a prior overnight fast	GCTcap - Diabetes n=1535 Participants capillary glucose measured 1 hour after a 50g oral glucose challenge, performed at any time during the day, without requiring a prior overnight fast	RPG - Diabetes n=1535 Participants random plasma glucose measured prior to administration of the 50g oral glucose challenge, at any time during the day, without requiring a prior overnight fast	RCG - Diabetes n=1535 Participants random capillary glucose measured prior to administration of the 50g oral glucose challenge, at any time during the day, without requiring a prior overnight fast	A1c - Diabetes n=1535 Participants hemoglobin A1c, measured at the time of the OGTT	GCTpl - Dysglycemia n=1535 Participants plasma glucose measured 1 hour after a 50g oral glucose challenge, performed at any time during the day, without requiring a prior overnight fast	GCTcap - Dysglycemia n=1535 Participants capillary glucose measured 1 hour after a 50g oral glucose challenge, performed at any time during the day, without requiring a prior overnight fast	RPG - Dysglycemia n=1535 Participants random plasma glucose measured prior to the 50g oral glucose challenge, performed at any time during the day, without requiring a prior overnight fast	RCG - Dysglycemia n=1535 Participants random capillary glucose measured prior to the 50g oral glucose challenge, performed at any time during the day, without requiring a prior overnight fast	A1c - Dysglycemia n=1535 Participants hemoglobin A1c, measured at the time of the OGTT
Ability of Different Screening Tests Which Can be Performed Opportunistically (During Outpatient Visits -- at Any Time of Day, Regardless of Meal Status) to Predict Findings With the Oral Glucose Tolerance Test (in the Morning, After an Overnight Fast)	.85 area under ROC curve Interval 0.78 to 0.91	.82 area under ROC curve Interval 0.75 to 0.89	.76 area under ROC curve Interval 0.69 to 0.82	.72 area under ROC curve Interval 0.65 to 0.8	.67 area under ROC curve Interval 0.57 to 0.76	.76 area under ROC curve Interval 0.72 to 0.8	.73 area under ROC curve Interval 0.69 to 0.77	.66 area under ROC curve Interval 0.62 to 0.71	.64 area under ROC curve Interval 0.59 to 0.68	.63 area under ROC curve Interval 0.58 to 0.68

SECONDARY outcome

Timeframe: 3 years

Cost was expressed as cost (dollars) to identify a single case, with cases defined as (i) diabetes or (ii) high-risk dysglycemia. Cost projections for screening were conducted from both Medicare and VA perspectives. All screening projections assumed follow-up testing with an OGTT if the screening test exceeded a 70% specificity cut-off.

Outcome measures

Outcome measures
Measure	GCTpl - Diabetes n=1535 Participants plasma glucose measured 1 hour after a 50g oral glucose challenge, performed at any time during the day, without requiring a prior overnight fast	GCTcap - Diabetes n=1535 Participants capillary glucose measured 1 hour after a 50g oral glucose challenge, performed at any time during the day, without requiring a prior overnight fast	RPG - Diabetes n=1535 Participants random plasma glucose measured prior to administration of the 50g oral glucose challenge, at any time during the day, without requiring a prior overnight fast	RCG - Diabetes n=1535 Participants random capillary glucose measured prior to administration of the 50g oral glucose challenge, at any time during the day, without requiring a prior overnight fast	A1c - Diabetes n=1535 Participants hemoglobin A1c, measured at the time of the OGTT	GCTpl - Dysglycemia n=1535 Participants plasma glucose measured 1 hour after a 50g oral glucose challenge, performed at any time during the day, without requiring a prior overnight fast	GCTcap - Dysglycemia n=1535 Participants capillary glucose measured 1 hour after a 50g oral glucose challenge, performed at any time during the day, without requiring a prior overnight fast	RPG - Dysglycemia n=1535 Participants random plasma glucose measured prior to the 50g oral glucose challenge, performed at any time during the day, without requiring a prior overnight fast	RCG - Dysglycemia random capillary glucose measured prior to the 50g oral glucose challenge, performed at any time during the day, without requiring a prior overnight fast	A1c - Dysglycemia hemoglobin A1c, measured at the time of the OGTT
Cost to Identify a Single Case of High-risk Dysglycemia or Previously Unrecognized Diabetes	100 Dollars	93 Dollars	42 Dollars	37 Dollars	133 Dollars	125 Dollars	55 Dollars	50 Dollars	—	—

Adverse Events

Group 1

Serious events: 0 serious events

Other events: 11 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Other adverse events
Measure	Group 1 n=1939 participants at risk Atlanta VA Medical Center patients who meet criteria for screening for prediabetes and early diabetes based on standard guidelines of the VA, the American Diabetes Association, and the National Institutes of Health
Metabolism and nutrition disorders hypoglycemia during OGTT	0.36% 7/1939 • Number of events 7
Metabolism and nutrition disorders hyperglycemia before 50g glucose challenge	0.10% 2/1939 • Number of events 2
Metabolism and nutrition disorders hyperglycemia after 50g glucose challenge	0.10% 2/1939 • Number of events 2

Additional Information

Lawrence S Phillips, MD

Atlanta VA Medical Center

Phone: 404-728-7608

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place