Prediabetes is a condition characterized by elevated blood glucose levels below the threshold for a diabetes diagnosis, but associated with an increased risk of developing diabetes. Impaired glucose tolerance (IGT) (2-h glucose 7.8–11.0 mol/L [140–199 mg/dL]) and impaired fasting glucose (IFG) (fasting glucose 6 ,1–6.9 mmol/L [110–125 mg/dL]), based on World Health Organization (WHO) criteria, are commonly used to define prediabetes . IGT tends to be characterized by insulin resistance in the muscle and decreased glucose uptake , while IFG is usually due to insulin resistance in the liver and excess hepatic glucose production . There is limited overlap between IGT and IFG; only 20-25% of people with IGT have IFG, and 30-45% of people with IFG have IGT.
Although IGT and IFG may reflect different but overlapping underlying pathogenic processes, individuals with IGT or IFG are at high risk of developing diabetes , with up to 50% progressing to diabetes within 5 years. People with IFG or IGT also have an elevated risk of chronic kidney disease, cardiovascular disease, and mortality. Intensive lifestyle intervention (eg, dietary modification and increased physical activity) and pharmacological intervention (eg, metformin) can significantly reduce the risk of progression to diabetes in people with IGT or IFG.
Characterizing the global prevalence of IGT and IFG is important for developing and implementing diabetes prevention policies and interventions worldwide. These data can also inform public health planning by highlighting populations at high risk of needing diabetes treatment and people who may need care for complications in the future. In 2019, the IDF Diabetes Atlas, 9th edition estimated that worldwide, 7.5% of adults aged 20 to 79 years, or 374 million people, had IGT, with the highest prevalence in North American and Caribbean countries. However, IGT only captures a portion of the prediabetes population. Characterizing the prevalence of IFG may provide a more complete assessment of the global burden of prediabetes, but Atlas 9 lacked high-quality data that could be used to generate reliable estimates.
Based on more than 80 high-quality contemporary studies, we estimate the global burden of prediabetes in 2021 using the WHO definitions of IFG and IGT and provide projections to 2045.
Aim
To estimate the global, regional and national prevalence of prediabetes, defined by impaired glucose tolerance (IGT) or impaired fasting glucose (IFG).
Methods
We reviewed 7014 publications for high-quality estimates of IGT (2-h glucose, 7.8–11.0 mmol/L [140–199 mg/dL]) and IFG (fasting glucose, 6.1–6.9 mmol/L [110–125 mg/L]). dL]) prevalence for each country. We used logistic regression to generate IGT and IFG prevalence estimates among adults aged 20 to 79 years in 2021 and projections to 2045. For countries without national data, we extrapolated estimates from countries with available data with geography, income, ethnicity, and language estimates. They were standardized according to the age distribution of each United Nations country.
Results
Approximately two-thirds of countries did not have high-quality IGT or IFG data. There were 50 high-quality studies for IGT from 43 countries and 43 high-quality studies for IFG from 40 countries. Eleven countries had data for both IGT and IFG. The global prevalence of IGT in 2021 was 9.1% (464 million) and is projected to increase to 10.0% (638 million) in 2045. The global prevalence of IFG in 2021 was 5.8% ( 298 million ) and is expected to increase to 6.5% ( 414 million ) in 2045.
The prevalence of IGT and IFG in 2021 was highest in high-income countries. In 2045, the greatest relative growth of IGT and IFG cases would be in low-income countries.
Conclusions In 2021, the age-adjusted prevalence of IGT and IFG was 9.1% (464 million) and 5.8% (298 million) among adults aged 20 to 79 years worldwide. The 2021 prevalence estimates for both IGT and IFG increased substantially with increasing age. The 2021 prevalence estimates for both IGT and IFG were highest in high-income countries, with the greatest relative growth in the number of people in 2045 with IGT and IFG in low-income countries. By 2045, the global prevalence of IGT and IFG is projected to increase to 10.0% (638 million) and 6.5% (414 million), respectively. In conclusion , the global burden of prediabetes based on the WHO definitions of IFG and IGT is substantial and increasing. Effective prevention is needed, especially in low-income countries, to curb the diabetes epidemic. High-quality data, currently unavailable for approximately two-thirds of the world’s countries, will be critical to global surveillance efforts. Achieving consensus definitions for prediabetes will facilitate comparisons of prevalence estimates across regions and times. Our findings highlight opportunities to improve epidemiological surveillance of prediabetes and the need to improve efforts to reduce its global burden. |
Reference : Global Prevalence of Prediabetes . Mary R. Rooney; Michael Fang; Katherine Ogurtsova; et al. Diabetes Care 2023;46(7):1388–1394 https://doi.org/10.2337/dc22-2376 PubMed: 37196350
