Objective: The incidence and evolution of prediabetes in older adults is still unclear. We aimed to estimate the incidence of prediabetes, the rates of prediabetes reverting to normoglycemia or progressing to type 2 diabetes, and to identify possible prognostic factors among older adults with prediabetes.

Methods: In the Swedish National Study on Aging and Care-Kungsholmen Project, 3049 diabetes-free participants aged ≥60 years were examined at baseline (2001-2004), and were followed-up to 12 years (2013-2016). At each wave, type 2 diabetes was ascertained based on self-report, antidiabetic drug use, medical records, or glycated haemoglobin (HbA1c) ≥6.5% (48 mmol/mol). In diabetes-free participants, prediabetes was assessed as HbA1c ≥5.7% (39 mmol/mol), and normoglycemia was defined as HbA1c <5.7%. Data were analysed with Poisson regression and multinomial logistic regression.

Results: During 12 years follow-up, among 1972 (64.7%) participants with normoglycemia, 505 (25.6%) developed prediabetes (incidence=4.3/100 person-years, 95% CI 3.9-4.8). Of the 1077 (35.3%) participants with prediabetes at baseline, 204 (18.9%) reverted to normoglycemia (reversion rate=3.1/100 person-years, 95% CI: 2.6-3.6) and 119 (11.0%) progressed to type 2 diabetes (progression rate=1.7/100 person-years, 95% CI: 1.3-2.1). The reversal to normoglycemia was significantly associated with lower systolic blood pressure and weight loss, while, obesity and weight gain were risk factors for progression to type 2 diabetes.

Conclusions: The incidence of prediabetes is high (about 26%) among older adults. Around 19% of people with prediabetes may revert to normoglycemia and 11% progress to type 2 diabetes. Weight change and systolic blood pressure may play a role in such evolution.