A single-sample confirmatory definition of diabetes had a high positive predictive value for subsequent diagnosis and was strongly associated with clinical end points, a recent study found. 13,346 participants from the Atherosclerosis Risk in Communities (ARIC) study (12,268 without diagnosed diabetes) were included with 25 years of follow-up for incident diabetes, cardiovascular outcomes, kidney disease, and mortality. Confirmed undiagnosed diabetes was defined as elevated levels of fasting glucose and HbA1c from a single blood sample. Researchers found:

• Among 12,268 participants without diagnosed diabetes, 978 had elevated levels of fasting glucose or HbA1c at baseline.
• 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.
• 15-year positive predictive value was 88.7% vs 71.1% for unconfirmed cases.
• Confirmed undiagnosed diabetes was significantly associated with CV and kidney disease and mortality, with stronger associations than unconfirmed diabetes.