While elevations in baseline fasting plasma glucose (FPG) are associated with risk of type 2 diabetes mellitus (DM) , some individuals with lower FPG will also develop DM. The aim of this study was to identify factors associated with DM in people with a baseline FPG of ≤ 80mg/dL. Using the population-based Rochester Epidemiology Project medical records linkage system, we identified subjects with ≥ 2 FPG tests from 2005-17, and a baseline FPG of ≤ 80mg/dL. Subjects who developed DM (FPG > 125mg/dL) were assigned an event date as the date of the 1st diagnostic value. Those who did not develop DM were censored at their last FPG. The median duration of follow-up was 7 years. The entire cohort consisted of 2315 subjects, of whom 130 (5.6%) developed DM. Using a nested case-control design we compared all 130 who progressed to diabetes (cases) to 491 randomly selected controls. Among the cases, 121 (93%) developed type 2 DM, 4 (3%) had type 1 DM, and 5 (4%) reverted to normal FPG on repeat. Cases were older, more commonly male, and had a higher BMI (see table) . Cases were more likely to have experienced a critical health event such as a malignancy diagnosis or exposure to high dose glucocorticoids. On extended follow up, 15% of cases were deceased.
In summary, progression to DM in individuals with a low-normal FPG at baseline typically occurs in the context of significant medical comorbidity and portends a poor prognosis.
S.Mohan: None. A.Vella: Advisory Panel; Crinetics Pharmaceuticals, Inc., Rezolute, Inc., vTv Therapeutics, Zealand Pharma A/S, Other Relationship; Novo Nordisk. A.M.Egan: None.
