IDF Diabetes Atlas: Global estimates for the prevalence of diabetes for 2015 and 2040.

AIM: To produce current estimates of the national, regional and global impact of diabetes for 2015 and 2040. METHODS: A systematic literature review was conducted to identify data sources on the prevalence of diabetes from studies conducted in the period from 1990 to 2015. An analytic hierarchy process was used to select the most appropriate studies for each country, and estimates for countries without data were modelled using extrapolation from similar countries that had available data. A logistic regression model was used to generate smoothed age-specific estimates, which were applied to UN population estimates. RESULTS: 540 data sources were reviewed, of which 196 sources from 111 countries were selected. In 2015 it was estimated that there were 415 million (uncertainty interval: 340-536 million) people with diabetes aged 20-79years, 5.0 million deaths attributable to diabetes, and the total global health expenditure due to diabetes was estimated at 673 billion US dollars. Three quarters (75%) of those with diabetes were living in low- and middle-income countries. The number of people with diabetes aged 20-79years was predicted to rise to 642 million (uncertainty interval: 521-829 million) by 2040. CONCLUSION: Diabetes prevalence, deaths attributable to diabetes, and health expenditure due to diabetes continue to rise across the globe with important social, financial and health system implications.

Global estimates of diabetes prevalence for 2013 and projections for 2035.

INTRODUCTION: Diabetes is a serious and increasing global health burden and estimates of prevalence are essential for appropriate allocation of resources and monitoring of trends. METHODS: We conducted a literature search of studies reporting the age-specific prevalence for diabetes and used the Analytic Hierarchy Process to systematically select studies to generate estimates for 219 countries and territories. Estimates for countries without available source data were modelled from pooled estimates of countries that were similar in regard to geography, ethnicity, and economic development. Logistic regression was applied to generate smoothed age-specific prevalence estimates for adults 20-79 years which were then applied to population estimates for 2013 and 2035. RESULTS: A total of 744 data sources were considered and 174 included, representing 130 countries. In 2013, 382 million people had diabetes; this number is expected to rise to 592 million by 2035. Most people with diabetes live in low- and middle-income countries and these will experience the greatest increase in cases of diabetes over the next 22 years. CONCLUSION: The new estimates of diabetes in adults confirm the large burden of diabetes, especially in developing countries. Estimates will be updated annually including the most recent, high-quality data available.

The IDF Diabetes Atlas methodology for estimating global prevalence of hyperglycaemia in pregnancy.

INTRODUCTION: Hyperglycaemia is one of the most prevalent metabolic disorders occurring during pregnancy. Limited data are available on the global prevalence of hyperglycaemia in pregnancy. The International Diabetes Federation (IDF) has developed a methodology for generating estimates of the prevalence of hyperglycaemia in pregnancy, including hyperglycaemia first detected in pregnancy and live births to women with known diabetes, among women of childbearing age (20-49 years). METHODS: A systematic review of the literature for studies reporting the prevalence of gestational diabetes was conducted. Studies were evaluated and scored to favour those that were representative of a large population, conducted recently, reported age-specific estimates, and case identification was based on blood test. Age-specific prevalence data from studies were entered to produce estimates for five-year age groups using logistic regression to smooth curves, with age as the independent variable. The derived age-specific prevalence was adjusted for differences in diagnostic criteria in the underlying data. Cases of hyperglycaemia in pregnancy were derived from age-specific estimates of fertility and age-specific population estimates. Country-specific estimates were generated for countries with available data. Regional and global estimates were generated based on aggregation and extrapolation for 219 countries and territories. Available fertility rates and diabetes prevalence estimates were used to estimate the proportion of hyperglycaemia in pregnancy that may be due to total diabetes in pregnancy - pregnancy in women with known diabetes and diabetes first detected in pregnancy. RESULTS: The literature review identified 199 studies that were eligible for characterisation and selection. After scoring and exclusion requirements, 46 studies were selected representing 34 countries. More than 50% of selected studies came from Europe and North America and Caribbean. The smallest number of identified studies came from sub-Saharan Africa. The majority of studies were for high-income countries, although low- and middle-income countries were also represented. CONCLUSION: Prevalence estimates of hyperglycaemia in pregnancy are sensitive to the data from which they are derived. The IDF methodology is a transparent, reproducible, and modifiable method for estimating the burden of hyperglycaemia in pregnancy. More data are needed, in particular from developing countries, to strengthen the methodology.

Global estimates of the prevalence of hyperglycaemia in pregnancy.

AIMS: We estimated the number of live births worldwide and by IDF Region who developed hyperglycaemia in pregnancy in 2013, including total diabetes in pregnancy (known and previously undiagnosed diabetes) and gestational diabetes. METHODS: Studies reporting prevalence of hyperglycaemia first-detected in pregnancy (formerly termed gestational diabetes) were identified using PubMed and through a review of cited literature. A simple scoring system was developed to characterise studies on diagnostic criteria, year study was conducted, study design, and representation. The highest scoring studies by country with sufficient detail on methodology for characterisation and reporting at least three age-groups were selected for inclusion. Forty-seven studies from 34 countries were used to calculate age-specific prevalence of hyperglycaemia first-detected in pregnancy in women 20-49 years. Adjustments were then made to account for heterogeneity in screening method and blood glucose diagnostic threshold in studies and also to align with recently published diagnostic criteria as defined by the WHO for hyperglycaemia first detected in pregnancy. Prevalence rates were applied to fertility and population estimates to determine regional and global prevalence of hyperglycaemia in pregnancy for 2013. An estimate of the proportion of cases of hyperglycaemia in pregnancy due to total diabetes in pregnancy was calculated using age- and sex-specific estimates of diabetes from the IDF Diabetes Atlas and applied to age-specific fertility rates. RESULTS: The global prevalence of hyperglycaemia in pregnancy in women (20-49 years) is 16.9%, or 21.4 million live births in 2013. An estimated 16.0% of those cases may be due to total diabetes in pregnancy. The highest prevalence was found in the South-East Asia Region at 25.0% compared with 10.4% in the North America and Caribbean Region. More than 90% of cases of hyperglycaemia in pregnancy are estimated to occur in low- and middle-income countries. CONCLUSION: These are the first global estimates of hyperglycaemia in pregnancy and conform to the new WHO recommendations regarding diagnosis and also include estimates of live births in women with known diabetes. They indicate the importance of the disease from a public health and maternal and child health perspective, particularly in developing countries.