Global, regional, and national cascades of diabetes care, 2000-23: a systematic review and modelling analysis using findings from the Global Burden of Disease Study.

Background: Diabetes is a serious global health challenge, with a rising prevalence and substantial effect on disability and mortality worldwide. Despite medical advancements, gaps in the cascade of diabetes care-comprising diagnosis, treatment, and glycaemic management-persist, hindering effective management. We aimed to comprehensively assess the state of the diabetes cascade of care globally, identifying areas of strength and needs for improvement in diabetes management.

Methods: Using data and methods from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD), this modelling analysis spanned the years 2000 to 2023 and covered 204 countries and territories. We systematically reviewed cross-sectional surveys that are representative of the general population and the published and grey literature to estimate the proportion of people with diabetes who are undiagnosed, diagnosed but untreated, receiving treatment with suboptimal glycaemic concentrations, and receiving treatment with optimal glycaemic concentrations. Treatment was defined as current use of insulin or other hypoglycaemic medication. We separately modelled these quantities by location, year, age, and sex using DisMod-MR 2.1, a hierarchical Bayesian meta-regression modelling tool, then scaled the estimates so that they sum to 100% of people living with diabetes in each stratum. Using GBD 2023 estimates of the number of people with diabetes, we calculated the diabetes cascade of care: proportion of people diagnosed among those with diabetes, proportion of people receiving treatment among those with diagnosed diabetes, and proportion of people with optimal glycaemic concentrations among those receiving treatment for diabetes across all strata.

Findings: In 2023, an estimated 55·8% (95% UI 49·3-62·3) of people with diabetes aged 15 years and older were diagnosed with diabetes globally. The proportion of people with diagnosed diabetes who were on treatment was 91·4% (88·0-94·2), and the proportion of people on diabetes treatment with optimal glycaemic concentrations was 41·6% (35·7-48·5). Among all people with diabetes, the proportion with optimal glycaemic concentrations on treatment was 21·2% (17·4-25·6) in 2023 globally. Substantial regional differences were observed, with the highest rates of diagnosis in high-income North America, the highest rates of treatment among those with diagnosed diabetes in high-income Asia Pacific, and the highest rates of optimal glycaemic concentrations among those receiving treatment for diabetes in southern Latin America. Between 2000 and 2023, globally, the proportion of people diagnosed with diabetes increased by 8·3 (6·6-10·0) percentage points, and the proportion of people receiving treatment among those diagnosed increased by 7·2 (5·7-8·8) percentage points. The proportion of people receiving treatment who had optimal glycaemic concentrations increased by 1·3 (0·8-1·8) percentage points.

Interpretation: Despite improvements over the past two decades, underdiagnosis and suboptimal glycaemic management of diabetes remain major challenges globally, particularly in low-income and middle-income countries. These findings highlight the urgent need for enhanced strategies and capacity building to improve the detection, treatment, and management of diabetes worldwide. Targeted interventions to bolster health-care systems' capacity to effectively diagnose and manage diabetes could lead to better health outcomes and reduce the burden of this growing disease.

Funding: Bill & Melinda Gates Foundation.