Diabetes mellitus is a chronic metabolic disease characterized by insulin resistance and elevated blood glucose levels. The global epidemiology of diabetes has demonstrated a significant increase in its prevalence and incidence in recent decades, making it a major public health concern (1). According to estimates from the Global Burden of Diseases (GBD), high blood glucose is ranked as the fifth leading cause of the global disease burden, and diabetes itself was identified as the seventh leading cause of death globally in 2021 (2, 3). There are two major types of diabetes: type 1 and type 2. Type 2 diabetes mellitus (T2DM) is strongly correlated with obesity and sedentary lifestyles (4). The global population of individuals living with diabetes was approximately 529 million in 2021, and T2DM accounts for up to 96% of these cases (1). The detrimental effects of T2DM manifest in various forms, including kidney disease, cardiovascular disease, and neurological damage (5, 6).

Chronic kidney disease (CKD) due to T2DM, as one of the most common microvascular complications of diabetes and the leading cause of end-stage renal disease, has surpassed 107 million worldwide in 2021 (7, 8). Therefore, CKD due to T2DM is not only a key challenge in diabetes management but also a core issue in the global prevention and control of chronic non-communicable diseases and the improvement of public health outcomes.

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (9). The COVID-19 pandemic has had a profound global impact since its emergence in 2019. Public health measures, such as lockdowns and closures of recreational facilities during the pandemic, have led to reduced physical activity and increased sedentary behaviors, potentially exacerbating the risk of metabolic diseases, including T2DM. Studies have reported a higher incidence of obesity and metabolic syndrome following the COVID-19 outbreak (10, 11). Additionally, COVID-19 may worsen preexisting diabetes cases and increase the likelihood of new-onset diabetes (12). Furthermore, the diversion of healthcare resources to COVID-19 response efforts and restrictions on non-essential healthcare services may have exacerbated the challenges in diabetes management and prevention. Furthermore, beyond the indirect effects of lockdowns, SARS-CoV-2 infection itself has been directly implicated in worsening glucose metabolism and increasing diabetes risk, as a growing body of evidence suggests that COVID-19 may exacerbate pre-existing diabetes and contribute to new-onset diabetes (12–16). Large cohort studies and meta-analyses have reported that individuals who recovered from COVID-19 exhibit a significantly increased incidence of new-onset diabetes compared to those with non-COVID respiratory infections (17). Similarly, patients with pre-existing diabetes have shown worse glycemic control and higher rates of adverse outcomes post-COVID-19 infection (18).

Based on previous evidence, we hypothesized that the burden of T2DM may increase in the post-pandemic era. Thus, we utilized the Global Burden of Disease (GBD) 2021 dataset to analyze trends in the T2DM burden over the pre-pandemic decade and the subsequent two years. Specifically, our objectives were to analyze the global and regional prevalence, incidence, mortality, and disability-adjusted life-years (DALYs) associated with T2DM among individuals aged 20 years and older; to evaluate the disease burden attributable to T2DM-related CKD; and to project the future burden of T2DM by the year 2030.

This study is the first systematic analysis to use the GBD 2021 dataset to estimate the T2DM burden following the COVID-19 pandemic in people aged over 20 years. A notable increase in the prevalence of diabetes was observed in the post-pandemic era.

Our analysis of GBD 2021 data indicates that the global burden of T2DM not only continued its long-term increasing trend but also accelerated in the post-pandemic era. This acceleration may be attributed to a confluence of direct and indirect pathways associated with the COVID-19 pandemic, which collectively exacerbated the global diabetes landscape. The direct biological effects of SARS-CoV-2 infection appear to play a significant role. Evidence suggests that the virus can directly infect pancreatic β-cells via ACE2 receptors, impairing insulin secretion and potentially accelerating β-cell apoptosis (21). Furthermore, the systemic inflammatory response and stress hyperglycemia during infection, compounded by the release of counter-regulatory hormones and the use of corticosteroids in treatment, can promote significant insulin resistance and hyperglycemia (22–24). These mechanisms are supported by large-scale clinical studies reporting a substantially higher incidence of new-onset diabetes among COVID-19 survivors compared to non-infected controls (25, 26), and are further reinforced by genetic evidence from Mendelian randomization studies indicating a bidirectional relationship between genetic susceptibility to COVID-19 and T2DM risk (27). Simultaneously, the indirect consequences of pandemic policies profoundly influenced population-level risk factors. Lockdowns and social restrictions led to widespread behavioral changes, including reduced physical activity (28–30) and increased weight gain (28, 29), which exacerbated known risk factors for T2DM such as overweight, obesity, poor diet, and physical inactivity (31). These changes adversely affected glycemic control in both the general population (32) and existing T2DM patients (32, 33), creating a conducive environment for diabetes progression and new cases. Therefore, the observed increase in global T2DM burden is not attributable to a single cause but rather results from the synergistic interaction of viral pathogenesis and pandemic-induced societal changes. This integrated explanation underscores the multifaceted impact of COVID-19 on diabetes dynamics, illuminating how biological and environmental factors collectively drove the accelerated disease burden.

A notable shift was observed following the COVID-19 pandemic: although the incidence, mortality, and DALYs related to T2DM continued to increase, their rates of growth slowed, contrasting sharply with the accelerated rise in prevalence. This pattern may be partially attributable to disruptions in healthcare access and documentation during the pandemic, which likely compromised the reporting of new T2DM cases. Furthermore, the observed attenuation in mortality growth may reflect misclassification of cause of death among diabetic patients—a population at elevated risk of severe COVID-19 outcomes (34). In cases where diabetic individuals contracted COVID-19 and died, the primary cause of death may have been assigned to COVID-19 rather than diabetes, leading to potential underestimation of diabetes-related mortality in official statistics. Thus, the apparent moderation in mortality and DALY growth should not be misinterpreted as a genuine reduction in the disease burden of diabetes, particularly given the concurrent increase in prevalence.

In high-SDI regions (e.g., Canada, the United Kingdom), T2DM prevalence increased markedly post-pandemic, yet mortality declined. Modernized clinical protocols emphasizing early intensive management may mitigate fatal outcomes despite growing disease burden. National diabetes prevention programs (e.g., the UK’s NHS Digital Weight Management Programme) achieved sustained engagement through digital modalities during lockdowns (35). These interventions likely accelerated case detection while reinforcing preventive messaging. Sodium-glucose co-transporter 2 inhibitors and glucagon-like peptide-1 receptor agonists are widely used (36), and these drugs exhibit cardiovascular protective effects beyond blood glucose control. Mortality declines could partially reflect competing risks – reduced physical activity during lockdowns theoretically increased obesity-driven incidence, but paradoxically lowered transport accidents/occupational injuries.

Our study also revealed that although the prevalence and incidence of T2DM in Indonesia and other comparable regions did not show a significant increase following the COVID-19 pandemic, there was a marked rise in DALYs attributable to T2DM. We propose that in low SDI regions such as Indonesia, pandemic-related constraints on healthcare resources severely disrupted routine diabetes screening, diagnosis, and chronic disease management (37). These disruptions likely led to considerable underdiagnosis and suboptimal management of T2DM. As a consequence, many cases may have only been identified at advanced stages, resulting not only in substantially higher medical costs but also in an increased risk of long-term complications and sequelae for patients (38, 39). Furthermore, although Oman and the United Arab Emirates ranked among the top countries in terms of T2DM prevalence and incidence growth, they did not feature prominently in mortality rankings. This may reflect the successful implementation of national diabetes management programs, early intervention strategies, and high-quality healthcare services that effectively reduce case fatality rates. It is also possible that these countries have younger diabetic populations or better-controlled comorbidities, which could attenuate mortality risk despite high disease burden (40).

WHO established the first global target for diabetes mellitus in 2022, highlighting the urgent need to address this growing health challenge (41). Given the substantial and growing number of COVID-19 cases, their impact on diabetes is likely to result in a significant population-level burden. In 2014, the United Kingdom launched the Diabetes Prevention Program to mitigate the risk of diabetes. The initial outcomes of this program in 2018 revealed stable or declining prevalence rates of T2DM, with expectations of further decline in subsequent years (42). However, the unexpected acceleration in the post-pandemic diabetes burden in the United Kingdom, as highlighted by this study, suggests the need for ongoing assessment and adaptation of previous strategies. Several measures can be taken to mitigate the burden of diabetes in the post-pandemic era. These include educating and screening patients with SARS-CoV-2 infection for diabetes, enhancing the healthcare system capacity to ensure ongoing monitoring and treatment for individuals with diabetes, and implementing policies that advocate healthy lifestyle choices, such as dietary habits and physical exercise, to mitigate diabetes risk.

This study has several limitations. First, we focused solely on the burden of T2DM, as it accounts for up to 96% of all diabetes cases (1); however, this approach may not fully capture the impact on other forms of diabetes. Second, the analysis is limited to data up to 2021 due to GBD data availability. The pandemic’s evolving nature, including vaccinations and new variants beyond 2021, may influence long-term trends and should be investigated in future updates. Third, shifts in health priorities and public health efforts during the pandemic may have disrupted disease surveillance and reporting systems, potentially leading to delays and underreporting. While the GBD provides comprehensive global estimates, it relies on modeled data that may be subject to regional heterogeneity, reporting delays, and methodological assumptions. Additionally, the GBD modeling approach may incorporate certain biases and uncertainties, and regional heterogeneity in data availability and quality could affect the generalizability of our findings. Finally, due to data lag and the rapidly changing context of the pandemic, the long-term health effects of COVID-19 require continued monitoring and accumulation of more comprehensive data.

In conclusion, the global burden of T2DM, particularly its rising prevalence and DALYs, has escalated rapidly in the wake of the pandemic. Addressing this trend demands urgent implementation of evidence-based strategies for both management and prevention. These should include individual-level interventions—such as glycemic monitoring and lifestyle modification programs—as well as broader policy measures, for example, sugar taxes, public health education campaigns, and integrated primary care initiatives aimed at early detection and multidisciplinary support. Learning from successful models globally will be essential to designing effective, context-sensitive responses.