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Prognostic Implications of Single-Sample Confirmatory Testing for Undiagnosed Diabetes: A Prospective Cohort Study.

TitlePrognostic Implications of Single-Sample Confirmatory Testing for Undiagnosed Diabetes: A Prospective Cohort Study.
Publication TypeJournal Article
Year of Publication2018
AuthorsSelvin E, Wang D, Matsushita K, Grams ME
Secondary AuthorsCoresh JJ
JournalAnn Intern Med
Volume169
Issue3
Pagination156-164
Date Published2018 08 07
ISSN1539-3704
KeywordsBlood Glucose, Diabetes Mellitus, Female, Glycated Hemoglobin A, Humans, Male, Middle Aged, Prognosis, Prospective Studies, Sensitivity and Specificity
Abstract

Background: Current clinical definitions of diabetes require repeated blood work to confirm elevated levels of glucose or hemoglobin A1c (HbA1c) to reduce the possibility of a false-positive diagnosis. Whether 2 different tests from a single blood sample provide adequate confirmation is uncertain.

Objective: To examine the prognostic performance of a single-sample confirmatory definition of undiagnosed diabetes.

Design: Prospective cohort study.

Setting: The ARIC (Atherosclerosis Risk in Communities) study.

Participants: 13 346 ARIC participants (12 268 without diagnosed diabetes) with 25 years of follow-up for incident diabetes, cardiovascular outcomes, kidney disease, and mortality.

Measurements: Confirmed undiagnosed diabetes was defined as elevated levels of fasting glucose (≥7.0 mmol/L [≥126 mg/dL]) and HbA1c (≥6.5%) from a single blood sample.

Results: Among 12 268 participants without diagnosed diabetes, 978 had elevated levels of fasting glucose or HbA1c at baseline (1990 to 1992). Among these, 39% had both (confirmed undiagnosed diabetes), whereas 61% had only 1 elevated measure (unconfirmed undiagnosed diabetes). The confirmatory definition had moderate sensitivity (54.9%) but high specificity (98.1%) for identification of diabetes cases diagnosed during the first 5 years of follow-up, with specificity increasing to 99.6% by 15 years. The 15-year positive predictive value was 88.7% compared with 71.1% for unconfirmed cases. Confirmed undiagnosed diabetes was significantly associated with cardiovascular and kidney disease and mortality, with stronger associations than unconfirmed diabetes.

Limitation: Lack of repeated measurements of fasting glucose and HbA1c.

Conclusion: A single-sample confirmatory definition of diabetes had a high positive predictive value for subsequent diagnosis and was strongly associated with clinical end points. Our results support the clinical utility of using a combination of elevated fasting glucose and HbA1c levels from a single blood sample to identify undiagnosed diabetes in the population.

Primary Funding Source: National Institute of Diabetes and Digestive and Kidney Diseases and National Heart, Lung, and Blood Institute.

DOI10.7326/M18-0091
Alternate JournalAnn Intern Med
PubMed ID29913486
PubMed Central IDPMC6082697
Grant ListR01 DK089174 / DK / NIDDK NIH HHS / United States
HHSN268201700001I / HL / NHLBI NIH HHS / United States
K24 DK106414 / DK / NIDDK NIH HHS / United States
HHSN268201700004I / HL / NHLBI NIH HHS / United States
HHSN268201700002I / HL / NHLBI NIH HHS / United States
HHSN268201700005I / HL / NHLBI NIH HHS / United States
HHSN268201700003I / HL / NHLBI NIH HHS / United States
R21 HL133694 / HL / NHLBI NIH HHS / United States