Background Type 2 diabetes is a complex metabolic disorder characterized by insulin resistance and progressive beta-cell dysfunction. Although sex differences in type 2 diabetes prevalence, progression, and complications have been reported, the molecular mechanisms underlying these differences remain largely unknown. We aimed to utilize single-cell RNA sequencing to identify a beta-cell cluster that is more prevalent in males than in females and exhibits distinct gene expression patterns, gene set enrichment profiles, and cell-cell communication compared to other clusters.
Methods FASTQ files from four public datasets were preprocessed, aligned to the human genome (GRCh38), and integrated into a high-quality matrix to mitigate batch effects. We focused on beta-cells from type 2 diabetes patients, performed trajectory inference to identify clusters, and conducted differential gene expression and gene set enrichment analyses. These findings were validated using bulk RNA-seq datasets. Additionally, cell-cell communication analysis was performed to identify ligand-receptor interactions, followed by a sensitivity analysis to assess sex-specific differences.
Results We identified a male-dominant beta-cell cluster (adjusted P value=4.2×10–6) that displayed unique gene expression patterns and downregulation of pathways associated with protein metabolism and insulin synthesis. Differentially expressed genes (e.g., interleukin 24 [IL24], regulator of G protein signaling like 1 [RGSL1]) were confirmed through bulk analysis. Moreover, the cluster demonstrated distinct communication patterns with other cell types, underscoring sex-specific differences.
Conclusion We have identified a male-dominant beta-cell cluster characterized by distinct gene expression, signaling pathways, and cell interactions. These findings provide insights into the pathophysiology of type 2 diabetes and may inform the development of more effective, sex-specific therapeutic strategies in the future.
Background This study investigated the association between the triglyceride-glucose (TyG) index, a marker of insulin resistance, and the risk of end-stage renal disease (ESRD) in individuals with type 2 diabetes mellitus (T2DM), focusing on variations by diabetes duration.
Methods We analyzed 1,219,148 Korean adults with T2DM from National Health Insurance Service data who underwent biennial health evaluations (2015 to 2016). ESRD was defined using specific procedural codes (V codes), and Cox proportional hazard models were employed to estimate hazard ratios (HRs) for ESRD across TyG index quartiles and diabetes duration categories, adjusting for various confounders.
Results Over 6,967,381 person-years of follow-up, 7,548 participants developed ESRD. Higher TyG index quartiles were independently associated with increased risk of ESRD, which was more pronounced with longer diabetes duration. The adjusted HR for ESRD in the highest TyG quartile (Q4) compared to the lowest quartile (Q1) was 1.235 (95% confidence interval [CI], 0.995 to 1.533) in new-onset diabetes, and 1.592 (95% CI, 1.465 to 1.730) in those with diabetes for ≥10 years. Compared to the lowest TyG quartile in new-onset diabetes, the adjusted HR for ESRD in the highest quartile with diabetes duration ≥10 years increased to 10.239 (95% CI, 8.440 to 12.422). Subgroup analysis revealed that a higher TyG index consistently increased the risk of ESRD, with stronger associations observed in younger individuals and those without comorbidities.
Conclusion The TyG index is a significant predictor of ESRD in T2DM, particularly in those with prolonged diabetes duration. Targeting insulin resistance early may mitigate the risk of ESRD in this population.
Korea has entered ‘super-aged’ society in 2025 with the proportion of people 65 years or older exceeding 20% as of the end of the year 2024. The health burden of cardiovascular diseases increases with age, and the increasing prevalence of cardiovascular risk factors, such as obesity, hypertension, diabetes mellitus, and dyslipidemia, may be linked to increased population-level cardiovascular risk. According to data from 2022, the overall prevalence of obesity reached 38.4%, marking a continued upward trend, based on National Health Insurance medical checkup data. In the combined data of 2021 to 2022, the prevalence of diabetes was 15.5% in Koreans older than 30 years according to the Diabetes Fact Sheet 2024 published by the Korean Diabetes Association, based on data from the Korean National Health and Nutrition Examination Survey. The prevalence of hypertension in the total population of Korea in 2022 was 30% according to the Korean Hypertension Fact Sheet produced by the Korean Society of Hypertension. Lastly, the prevalence of dyslipidemia in 2022 was 40.9% according to the Dyslipidemia Fact Sheet published by the Korean Society of Lipid and Atherosclerosis. In this article, I would like to review the prevalence and current management of cardiovascular risk factors in Korea according to the fact sheets released by various associations in 2024.
Background This study aimed to assess whether markers of diabetes severity could serve as predictors for foot amputation risk among patients with type 2 diabetes mellitus.
Methods We analyzed data from the nationally representative Korean National Health Insurance System database, tracking 2,544,077 patients with type 2 diabetes mellitus who participated in routine health check-ups between 2009 and 2012, with followup extending through the end of 2018. The parameters used to define the diabetes severity score encompassed diabetes duration, insulin usage, the number of oral glucose-lowering medications, the presence of chronic kidney disease, diabetic retinopathy, and cardiovascular disease. Each factor was assigned one point, yielding a cumulative severity score ranging from 0 to 6.
Results The risk of diabetic foot amputation was predominantly predicted by insulin therapy, diabetic retinopathy, and a prolonged duration of diabetes. The hazard ratios for foot amputation increased with the severity score as follows: 2.31 (95% confidence interval [CI], 2.15 to 2.47) for a score of 1, 4.73 (95% CI, 4.42 to 5.07) for a score of 2, 8.86 (95% CI, 8.24 to 9.53) for a score of 3, 16.95 (95% CI, 15.60 to 18.4) for a score of 4, 23.98 (95% CI, 21.25 to 27.05) for a score of 5, and 37.87 (95% CI, 28.93 to 49.57) for a score of 6.
Conclusion Specific markers of advanced diabetes effectively identified patients at an elevated risk for diabetic foot amputation.
Continuous glucose monitoring (CGM) has revolutionized diabetes management, significantly enhancing glycemic control across diverse patient populations. Recent evidence supports its effectiveness in both type 1 and type 2 diabetes management, with benefits extending beyond traditional glucose monitoring approaches. CGM has demonstrated substantial improvements in glycemic control across multiple metrics. Studies report consistent glycosylated hemoglobin reductions of 0.25%–3.0% and notable time in range improvements of 15%–34%. CGM effectively reduces hypoglycemic events, with studies reporting significant reductions in time spent in hypoglycemia. CGM also serves as an educational tool for lifestyle modification, providing real-time feedback that helps patients understand how diet and physical activity affect glucose levels. While skin-related complications remain a concern, technological advancements have addressed many initial concerns. High satisfaction rates and long-term use suggest that device-related issues are manageable with proper education and support. Despite high initial costs, CGM’s prevention of complications and hospitalizations ultimately reduces healthcare expenditures. With appropriate training and support, CGM represents a transformative technology for comprehensive diabetes care.
Background Dapagliflozin, a sodium-glucose cotransporter 2 inhibitor, reduces hyperglycemia and obesity by inhibiting renal glucose reabsorption. This post hoc study evaluated clinical factors influencing patient response to dapagliflozin.
Methods The analysis focused on patients treated with dapagliflozin (10 mg/day for 52 weeks) within the randomized, double-blind, parallel-group BEYOND trial. Adequate glycemic control (GC) was defined as a reduction in glycated hemoglobin (HbA1c) of ≥ 1.0% or the achievement of an HbA1c level <7.0% at week 52. Significant weight loss (WL) referred to a reduction in body weight of ≥3.0% at week 52. Participants were classified into four groups based on their GC and WL responses: GC+/WL+, GC+/WL−, GC−/WL+, and GC−/WL−.
Results Among dapagliflozin recipients (n=56), at 52 weeks, HbA1c had decreased by 1.0%±0.8% from baseline, while body weight had declined by 2.4±3.1 kg. Overall, 69.6% of participants achieved GC+, and 57.1% achieved WL+. Male sex and shorter diabetes duration were significantly associated with achieving GC+. Conversely, higher estimated glomerular filtration rate was significantly linked to WL+. The only factor significantly associated with both GC+ and WL+ was shorter diabetes duration (odds ratio, 0.81; 95% confidence interval, 0.68 to 0.97; P=0.023). The GC+ and WL+ groups exhibited favorable responses beginning soon after dapagliflozin therapy was initiated. Furthermore, HbA1c decline was more strongly associated with reduction in visceral fat than with WL.
Conclusion A short duration of diabetes and early response to treatment appear to represent key factors in maximizing the benefits of dapagliflozin for blood glucose and weight management.
Background We aimed to assess the association between triglyceride-glucose (TyG) index and cardiovascular disease (CVD) risk and mortality in a large cohort of diabetes patients.
Methods A retrospective cohort study of 1,090,485 participants from the Korean National Health Insurance Service database was conducted. Participants were stratified into TyG quartiles.
Results Higher TyG index quartiles were significantly associated with an increased CVD risk and mortality risk. In fully adjusted models, participants in the highest TyG quartile (Q4) had an 18% higher risk of CVD (hazard ratio [HR], 1.18; 95% confidence interval [CI], 1.13 to 1.23) and a 16% higher risk of mortality (HR, 1.16; 95% CI, 1.11 to 1.23) compared to those in the lowest quartile (Q1). The association was particularly pronounced in patients with fasting glucose ≥126 mg/dL (CVD [HR, 1.33; 95% CI, 1.29 to 1.37], mortality [HR, 1.23; 95% CI, 1.20 to 1.26]; P for interaction <0.001). Patients with a diabetes duration of ≥10 years showed the strongest association between the TyG index and CVD risk (HR, 1.44; 95% CI, 1.38 to 1.50), while the mortality risk was particularly elevated in those with a diabetes duration of less than 5 years (HR, 1.23; 95% CI, 1.18 to 1.30). Subgroup analyses revealed stronger associations between TyG index and CVD risk in younger participants, non-obese individuals, and non-smokers.
Conclusion The TyG index is a significant predictor of CVD and mortality in diabetic patients, particularly in those with poor glycemic control or longer disease duration.
Background This study investigated the prevalence of diabetes mellitus (DM) and impaired fasting glucose, as well as their management and comorbidities among older Korean adults.
Methods Data from 269,447 individuals aged 65 years and older from the Korean National Health Insurance Service between 2000 and 2019 were analyzed to evaluate trends in DM prevalence, healthcare utilization, mortality, and complications.
Results Among 269,447 individuals, 18.6% (n=50,159/269,447) were diagnosed with DM and 27.0% (n=72,670/269,447) had impaired fasting glucose. The DM group had the highest body mass index, waist circumference, and prevalence of current smokers (P<0.001) but not the highest hypertension prevalence. From 2010 to 2019, the prevalence of DM and impaired fasting glucose increased from 15.5% to 21.9% and from 26.0% to 30.6%, respectively. Cancer-related mortality in DM was 1.15 times higher than in those with normal glucose tolerance (P<0.001), and cardiovascular disease-related mortality was 1.32 times higher (P<0.001); all mortalities were higher in female participants. Myocardial infarction (hazard ratio [HR], 1.34; P<0.001), stroke (HR, 1.24; P<0.001), and heart failure (HR, 1.13; P<0.001) were significantly higher in those with DM.
Conclusion This is the first study to investigate the prevalence of DM and related complications in older individuals based on longterm representative data in Korea. These results highlight the necessity for targeted interventions to enhance management and outcomes in this population.
Background We examined the distribution of time to insulin therapy (TIT) post-diabetes diagnosis and the hazard of severe hypoglycemia (SH) according to TIT in Korean adults initially diagnosed with type 2 diabetes (T2D) and who progressed to insulin therapy.
Methods Using data from the Korean National Health Insurance Service (2002 to 2018), we selected adult incident insulin users (initially diagnosed as T2D) who underwent health examinations between 2009 and 2012. The hazards of SH, recurrent SH, and problematic hypoglycemia were analyzed according to groups categorized using the TIT and clinical risk factors for SH (TIT ≥5 years with risk factors, TIT ≥5 years without risk factors, 3 ≤TIT <5 years, 1 ≤TIT <3 years, and TIT <1 year).
Results Among 41,637 individuals, 14,840 (35.64%) and 10,587 (25.43%) initiated insulin therapy within <5 and <3 years postdiabetes diagnosis, respectively. During a median 6.53 years, 3,406 SH events occurred. Compared to individuals with TIT ≥5 years and no risk factor for SH, individuals with TIT <3 years had higher outcome hazards in a graded manner (adjusted hazard ratio [95% confidence intervals] for any SH: 1.117 [0.967 to 1.290] in those with 3 ≤TIT <5 years; 1.459 [1.284 to 1.657] in those with 1 ≤ TIT <3 years; and 1.515 [1.309 to 1.754] in those with TIT <1 year). This relationship was more pronounced in the non-obese subpopulation.
Conclusion Among adults who progressed to insulin therapy after being diagnosed with T2D, a shorter TIT was not uncommon and may predict an increased risk of SH, particularly in non-obese patients.
Gestational diabetes mellitus (GDM) affects over 10% of all pregnancies, both in Korea and worldwide. GDM not only increases the risk of adverse pregnancy outcomes such as preeclampsia, preterm birth, macrosomia, neonatal hypoglycemia, and shoulder dystocia, but it also significantly increases the risk of developing postpartum type 2 diabetes mellitus and cardiovascular disease in the mother. Additionally, GDM is linked to a higher risk of childhood obesity and diabetes in offspring, as well as neurodevelopmental disorders, including autistic spectrum disorder. This review offers a comprehensive summary of clinical epidemiological studies concerning maternal and fetal complications and explores mechanistic investigations that reveal the underlying pathophysiology.
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In East Asians, type 2 diabetes mellitus (T2DM) is primarily characterized by significant defects in insulin secretion and comparatively low insulin resistance. Recently, the prevalence of T2DM has rapidly increased in East Asian countries, including Korea, occurring concurrently with rising obesity rates. This trend has led to an increase in the average body mass index among East Asian T2DM patients, highlighting the influence of insulin resistance in the development of T2DM within this group. Currently, the incidence of T2DM in Korea is declining, which may indicate potential adaptive changes in insulin secretory capacity. This review focuses on the changing epidemiology of T2DM in East Asia, with a particular emphasis on the characteristics of peak functional β-cell mass.
Background Data on the carcinogenic potential of tirzepatide from randomized controlled trials (RCTs) are limited. Furthermore, no meta-analysis has included all relevant RCTs to assess the cancer risk associated with tirzepatide.
Methods RCTs involving patients receiving tirzepatide in the intervention arm and either a placebo or any active comparator in the control arm were searched through electronic databases. The primary outcome was the overall risk of any cancer, and secondary outcomes were the risks of specific types of cancer in the tirzepatide versus the control groups.
Results Thirteen RCTs with 13,761 participants were analyzed. Over 26 to 72 weeks, the tirzepatide and pooled control groups had identical risks of any cancer (risk ratio, 0.78; 95% confidence interval, 0.53 to 1.16; P=0.22). The two groups had comparable cancer risks in patients with and without diabetes. In subgroup analyses, the risks were also similar in the tirzepatide versus placebo, insulin, and glucagon-like peptide-1 receptor agonist groups. The overall cancer risk was also comparable for different doses of tirzepatide compared to the control groups; only a 10-mg tirzepatide dose had a lower risk of any cancer than placebo. Furthermore, compared to the control groups (pooled or separately), tirzepatide did not increase the risk of any specific cancer types. Despite greater increments in serum calcitonin with 10- and 15-mg tirzepatide doses than with placebo, the included RCTs reported no cases of papillary thyroid carcinoma.
Conclusion Tirzepatide use in RCTs over 26 to 72 weeks did not increase overall or specific cancer risk.
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Background Achieving optimal glucose control is essential in the management of type 2 diabetes (T2D). This study aimed to evaluate the effectiveness and safety of oral quadruple combination therapy for the treatment of T2D.
Methods This meta-analysis reviewed original research on oral quadruple combination therapy for T2D, including both experimental and observational studies with a minimum duration of 12 weeks. The primary endpoint was the change in glycated hemoglobin (HbA1c) from baseline to follow-up. The secondary endpoint was the incidence rate of adverse events. Two investigators independently extracted data and assessed the risk of bias. Outcomes were pooled as the standardized mean difference (using Hedge’s g) and the risk ratio for adverse events in random-effects meta-analyses.
Results The meta-analysis included 17 studies. Oral quadruple combination therapy resulted in an additional mean reduction in HbA1c levels of 1.1% in patients who did not achieve glycemic control with oral triple combination therapy. Compared with switching to injectables, such as insulin or a glucagon-like peptide-1 receptor agonist–containing regimen, this therapy was non-inferior, even demonstrating a slightly superior glucose-lowering effect. Furthermore, it was determined to be safe, with an adverse event rate of 0.25, indicating no significant difference in safety compared with adding a placebo or switching to an injectable-containing regimen.
Conclusion Oral quadruple combination therapy is a valid option for patients with T2D who are unable to achieve glycemic targets with oral triple combination therapy, offering both effective glycemic control and a favorable safety profile.
Background Gestational diabetes mellitus (GDM) affects women with diverse pathological phenotypes, but little is known about the effects of this variation on perinatal outcomes. We explored the metabolic phenotypes of GDM and their impact on adverse pregnancy outcomes.
Methods Women diagnosed with gestational glucose intolerance or GDM were categorized into subgroups according to their prepregnancy body mass index (BMI) and the median values of the gestational Matsuda and Stumvoll indices. Logistic regression analysis was employed to assess the odds of adverse pregnancy outcomes, such as large-for-gestational age (LGA), small-for-gestational age, preterm birth, low Apgar score, and cesarean section.
Results A total of 309 women were included, with a median age of 31 years and a median BMI of 22.3 kg/m2. Women with a higher pre-pregnancy BMI had a higher risk of LGA newborns (adjusted odds ratio [aOR] for pre-pregnancy BMI ≥25 kg/m2 compared to 20–23 kg/m2, 4.26; 95% confidence interval [CI], 1.99 to 9.12; P<0.001; P for trend=0.001), but the risk of other adverse pregnancy outcomes did not differ according to pre-pregnancy BMI. Women with insulin resistance had a higher risk of LGA (aOR, 1.88; 95% CI, 1.02 to 3.47; P=0.043) and cesarean section (aOR, 2.12; 95% CI, 1.29 to 3.50; P=0.003) than women in the insulin-sensitive group. In contrast, defective β-cell function did not affect adverse pregnancy outcomes.
Conclusion Different metabolic phenotypes of GDM were associated with heterogeneous pregnancy outcomes. Women with obesity and those with insulin resistance are at greater risk of adverse outcomes and might need strict glycemic management during pregnancy.
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In the context of a global shortage of glucagon-like peptide-1 (GLP-1) receptor agonists, we assessed the impact of discontinuing dulaglutide on metabolic control in individuals with type 2 diabetes. Our analysis included data from 69 individuals and revealed a significant deterioration in glycemic control following the discontinuation. Specifically, the average hemoglobin A1c level increased from 7.0%±0.9% to 8.1%±1.4% (P<0.001), and fasting glucose levels rose from 129±31 to 156±50 mg/dL (P<0.001) within 3 months after stopping the medication. Alternative treatments such as dipeptidyl peptidase-4 inhibitors and sodium glucose cotransporter- 2 inhibitors were insufficient substitutes, highlighting the essential role of continuous GLP-1 receptor agonist therapy in maintaining metabolic health.