Prediabetes in Ontario: improving surveillance for better disease prevention

Prediabetes, a metabolic state preceding type 2 diabetes (T2D), is independently associated with increased all-cause mortality. Despite its growing public health significance, population-level estimates of prediabetes burden remain limited. We examined temporal trends in the incidence and prevalence of prediabetes in Ontario, stratified by age, sex, and key sociodemographic factors.

This retrospective cohort study used data from the Ontario Laboratories Information System (2015-2024). Prediabetes was defined using laboratory criteria: glycated hemoglobin 6.0% and 6.4%, or impaired glucose tolerance (2-hour glucose of 7.8-11.0 mmol/L after a 75 g oral glucose tolerance test), or impaired fasting glucose (6.1-6.9 mmol/L). Analyses included individuals aged 20-105 years with valid glucose testing and excluded results in the diabetes range.

Age-standardized incidence increased by 20% from 15.2 per 1,000 persons in 2015 to 18.2 per 1,000 in 2024, while prevalence increased by 25% from 11% in 2015 to 14% in 2024. These increases were observed in both sexes. Incidence and prevalence were higher in socioeconomically disadvantaged and urban communities.

Prediabetes incidence and prevalence increased substantially in Ontario between 2015 and 2024, with a disproportionate burden in lower socioeconomic and urban communities, underscoring the need for targeted prevention and screening strategies.