{
  "abstract": "Aims To investigate whether oral glucose tolerance test (OGTT) 1-hour plasma glucose (1-h PG) concentration can be used as the criterion for diagnosing diabetes mellitus (DM) and pre-diabetes.Materials and methods Data were collected from 1021 outpatients who completed a 5-point OGTT. The χ 2 test was used to compare the prevalence of diabetes and pre-diabetes based on OGTT 1-h and 2-h PG (2-hour PG) according to different criteria. Cohen’s Kappa test and receiver operating characteristic curves (ROC curves) were used to evaluate the diagnostic value of OGTT 1-h PG for diabetes and pre-diabetes.Results The prevalence rates of diabetes and pre-diabetes were 34.1% and 24.4% based on the American Diabetes Association (ADA) standard, 42.4% and 21.8% when OGTT 2-h PG was replaced with OGTT 1-h PG, and 44.4% and 20.8% when the OGTT 1-h PG was added to the ADA criteria. According to the WHO criteria, the prevalence rates of diabetes and pre-diabetes were 30.4% and 19.2%, 40.5% and 21.8% when OGTT 2-h PG was replaced with OGTT 1-h PG, and 43.9% and 22.2% when the OGTT 1-h PG was added to the WHO criteria. Substituting OGTT 1-h PG for OGTT 2-h PG in the ADA diagnostic strategy still retained good consistency for both diabetes (κ=0.7, 95% CI 70.1% to 78.4%) and pre-diabetes (κ=0.7, 95% CI 64.5% to 75.0%). For diabetes, the area under the curves (AUC) was 93.7% (95% CI 92.2% to 95.1%) for OGTT 1-h PG and 96.1% (95% CI 94.7% to 97.3%) for OGTT 2-h PG. For pre-diabetes, the AUC was 71.8% (95% CI 67.9% to 75.8%) for OGTT 1-h PG and 70.4% (95% CI 65.9% to 74.5%) for OGTT 2-h PG.Conclusions The DM prevalence would be significantly higher if the OGTT 1-h PG was adopted as the diagnostic criterion. More prospective studies are needed to validate its clinical utility.",
  "authors": [
    {
      "affiliations": [
        "Department of Endocrinology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China"
      ],
      "name": "Lina Chen"
    },
    {
      "affiliations": [
        "Department of Clinical Laboratory, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China"
      ],
      "name": "Bingxian Bian"
    },
    {
      "affiliations": [
        "Department of Endocrinology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China"
      ],
      "name": "Hui Ran"
    },
    {
      "affiliations": [
        "Department of Endocrinology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China"
      ],
      "name": "Yixin Niu"
    },
    {
      "affiliations": [
        "Department of Endocrinology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China"
      ],
      "name": "Yanbo Li"
    },
    {
      "affiliations": [
        "Department of Endocrinology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China"
      ],
      "name": "Qing Su"
    },
    {
      "affiliations": [
        "Department of Endocrinology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China"
      ],
      "name": "Hongmei Zhang"
    }
  ],
  "full_text": "WHAT IS ALREADY KNOWN ON THIS TOPIC The International Diabetes Federation has proposed using the oral glucose tolerance test (OGTT) 1-h plasma glucose (1-h PG) as a diagnostic criterion for diabetes and pre-diabetes.WHAT THIS STUDY ADDS Diabetes mellitus prevalence would be significantly higher if the OGTT 1-h PG was adopted as the diagnostic criterion.HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY Compared with OGTT 2-hour PG (2-h PG), OGTT 1-h PG has similar efficacy in diagnosing diabetes, but it will significantly increase the prevalence of diabetes.More prospective studies are needed to validate its clinical utility.Introduction According to the International Diabetes Federation (IDF) statement, approximately 589 million individuals (11.11% of adults population) were suffering from diabetes in 2024 and it is assumed that 853 million people (12.96% of the adult population) will have diabetes by 2050. 1 Type 2 diabetes (T2D) is a major public health concern with high morbidity and mortality and causes a high socioeconomic burden.2 Pre-diabetes will rapidly progress to T2D without optimal interventions. Therefore, it is necessary to screen high-risk populations using a more sensitive method.3 Early screening and diagnosis can help slow down the progression of pre-diabetes to diabetes by facilitating early interventions such as lifestyle modification.In 1979, the National Diabetes Data Group and WHO proposed diagnosing diabetes using fasting plasma glucose (FPG) ≥140 mg/dL (7.8 mmol/L) or oral glucose tolerance test (OGTT) 2-hour plasma glucose (2-h PG) ≥200 mg/dL (11.1 mmol/L).4 Over the next 20 years, the diagnostic criteria for diabetes have undergone two major updates. At the end of the 1990s, WHO adjusted the diagnostic standard for FPG from 140 mg/dL (7.8 mmol/L) to 126 mg/dL (7.0 mmol/L).5 6 At the end of the 2000s, the American Diabetes Association (ADA) added hemoglobin A1c (HbA1c) ≥6.5% (48 mmol/mol) as a diagnostic standard for diabetes.7 The WHO, ADA, and the International Expert Committee (IEC) have not reached an agreement on the diagnostic criteria for pre-diabetes and advocate using FPG, OGTT 2-h PG, HbA1c, or their combinations to define pre-diabetes.8As the study of the heterogeneity of diabetes progresses, we may need to re-examine the existing diagnostic criteria and explore more sensitive and individualized diagnostic methods, especially in terms of their applicability across different populations and regions globally. Considerable evidence has shown that an elevated OGTT 1-h PG could identify individuals at high risk for T2D among those with normal glucose tolerance, and IDF proposed using OGTT 1-h PG as the diagnostic standard for T2D and pre-diabetes.9 This recommendation is now being evaluated in specific high-risk populations. A recent study in women with gestational diabetes demonstrated that an antenatal 1-h PG ≥209 mg/dL (11.6 mmol/L) was associated with a significantly higher risk of postpartum diabetes and adverse cardiometabolic profiles, highlighting the potential of 1-h PG for risk stratification in clinical practice.10 Emerging evidence from diverse ethnic populations has begun to evaluate this recommendation. A multi-cohort study across Western Europe and East Asia demonstrated that 1-h PG exhibited superior diagnostic performance compared with FPG, 2-h PG, and HbA1c, with pooled area under the curves (AUC) of 0.97 vs 0.85 for the combination of FPG and HbA1c.11 However, studies in African-born Blacks suggested that the 1-h PG threshold ≥209 mg/dL (11.6 mmol/L) may have inadequate sensitivity in non-obese individuals with β-cell failure, proposing a lower optimal cut-off of 183 mg/dL (10.2 mmol/L).12 A Singaporean study in pregnancy demonstrated distinct OGTT phenotypes across ethnic groups: Indians exhibited predominantly FPG abnormalities, Chinese displayed FPG or 2-h PG abnormalities, Malays actually had the lowest overall prevalence of hyperglycemia, and no significant ethnic differences were observed for 1-h PG abnormalities.13 In the present study, we aim to investigate the effect of OGTT 1-h PG as a diagnostic criterion on the prevalence of diabetes and pre-diabetes in a Chinese population and to explore its feasibility as a diagnostic standard.Materials and methods Subjects The flow diagram of participants’ recruitment is presented in online supplemental figure 1. We consecutively enrolled 4215 outpatients who first visited our clinic for diabetes screening between 2012 and 2016. After excluding patients without OGTT (n=159), without complete medical records (n=465), or only with 2-point glucose test (fasting and 2 hours, n=2570), 1021 participants with complete 5-point OGTT data were included.SP110.1136/bmjdrc-2025-005689.supp1Supplementary dataOral glucose tolerance test The participants were instructed to maintain a regular diet and activity for at least 3 days before the test, and the carbohydrate content of the diet was not less than 150 g/day. Drugs that could interfere with glucose metabolism were also discontinued for at least 3 days, and oral contraceptives were discontinued for more than 1 week. After fasting for at least 10 hours, the participants were required to take 75 g glucose orally within 5 min, and venous blood samples were drawn at 0, 30, 60, 120, and 180 min to measure the plasma glucose, C-peptide, insulin concentrations, and HbA1c.Pre-diabetes Pre-diabetes includes impaired fasting glucose (IFG) and impaired glucose tolerance (IGT). In addition to the above glucose indices, the ADA uses HbA1c as a diagnostic criterion for pre-diabetes.Laboratory determinations We collected data on gender, age, blood pressure, body mass index (BMI), FPG, OGTT 1-h PG, OGTT 2-h PG, HbA1c, fasting C-peptide, fast insulin (FIN), and lipid profiles. Gender, age, blood pressure, and BMI were collected by medical staff. The plasma glucose concentration was measured using the enzymatic hexokinase photometric assay (Hitachi 7600, Tokyo, Japan). HbA1c was determined using high-performance liquid chromatography (BIO-RAD VARIANT II, California, USA). The fasting insulin was determined using chemiluminescent immunoassays (ADVIA Centaur XP, Siemens, Berlin, Germany). The fasting C-peptide was determined using chemiluminescent immunoassays (Roche e601, Leverkusen, Germany). Homeostasis model assessment of insulin resistance (HOMA-IR) was derived according to the following formula: HOMA−IR=FINS(μU/mL)×FPG(mmol/L)22.5.Statistical analysis The data were analyzed using SPSS V.22.0 software (SPSS, Chicago, Illinois, USA) and Python V.3.10.14. The baseline characteristics were expressed as mean±SD or n (%). P value was calculated using independent samples t-test. We used the χ 2 test to compare the prevalence of diabetes mellitus (DM) and pre-diabetes based on the different criteria. The consistency between OGTT 2-h PG and OGTT 1-h PG in the diagnosis of diabetes and pre-diabetes was assessed using the Cohen’s Kappa test. ROC curves were used to compare the diagnostic performance of OGTT 1-h PG with that of OGTT 2-h PG for identifying diabetes and pre-diabetes.Results Baseline characteristics of participants were presented in table 1. Participants were classified into diabetes and non-diabetes groups based on current ADA OGTT criteria. Compared with participants without diabetes, those with diabetes were older, more likely to be male, and had higher BMI, blood pressure, glucose levels (FPG, OGTT 1-h PG, OGTT 2-h PG, HbA1c), and insulin resistance (all p<0.001). No significant differences were observed in lipid profiles between the two groups.Table 1Baseline characteristics of diabetes and non-diabetes based on ADA OGTT criteriaCharacteristicsDiabetes (n=310)Non-diabetes (n=711)P valueAge (years)60.0±13.652.6±17.9<0.001Male, n (%)186 (60.0)304 (42.7)<0.001BMI (kg/m2)26.2±3.223.3±5.2<0.001SBP (mm Hg)137.0±17.8124.8±20.4<0.001DBP (mm Hg)82.4±9.078.0±10.2<0.001TC (mg/dL)189.2±54.1181.5±42.50.208TG (mg/dL)194.7±239.0194.7±601.80.899HDL-C (mg/dL)50.2±23.250.1±19.30.148LDL-C (mg/dL)112.0±38.6108.1±30.90.070FPG (mg/dL)133.2±43.288.2±12.6<0.001OGTT 1-h PG (mg/dL)282.6±72.0156.6±52.2<0.001OGTT 2-h PG (mg/dL)277.2±81.0113.4±37.8<0.001HbA1c (%)7.5±1.85.8±0.5<0.001HOMA-IR2.9±1.81.7±0.9<0.001ADA, American Diabetes Association; DBP, diastolic blood pressure; HbA1c, hemoglobin A1c; HDL-C, high-density lipoprotein cholesterol; HOMA-IR, homeostasis model assessment of insulin resistance; 1-h PG, 1-hour plasma glucose; 2-h PG, 2-hour plasma glucose; LDL-C, low-density lipoprotein cholesterol; OGTT, oral glucose tolerance test; SBP, systolic blood pressure; TC, total cholesterol; TG, triglyceride.As table 2 showed, the prevalence of DM was 34.1% (348 people) according to the current ADA standards and 42.4% (433 people, p<0.001) when we replaced the OGTT 2-h PG with OGTT 1-h PG according to the ADA criteria. The prevalence of DM was 44.4% (453 people, p<0.001) when we added OGTT 1-h PG to the ADA criteria, which was significantly higher than that for the current ADA diagnostic standards. Similarly, the prevalence of DM was 30.4% (310 people) according to the current WHO standards, and 40.5% (414 people, p<0.001) when we replaced the OGTT 2-h PG with OGTT 1-h PG according to the WHO criteria. The prevalence of DM increased to 43.9% (438 people, p<0.001) when OGTT 1-h PG was added to the traditional WHO diagnostic standards, which was significantly elevated compared with the current WHO diagnostic standards.Table 2Prevalence of diabetes by different diagnostic strategies based on ADA and WHO standardsDiagnostic strategyADA standardNWHO standardNCurrent criteria FPG≥126 mg/dL (7.0 mmol/L)142≥126 mg/dL (7.0 mmol/L)142 OGTT 2-h PG≥200 mg/dL (11.1 mmol/L)288≥200 mg/dL (11.1 mmol/L)288 HbA1c≥6.5% (48 mmol/mol)203–– Total (%)348 (34.1)310 (30.4)OGTT 1-h PG replacement FPG≥126 mg/dL (7.0 mmol/L)142≥126 mg/dL (7.0 mmol/L)142 OGTT 1-h PG≥209 mg/dL (11.6 mmol/L)407≥209 mg/dL (11.6 mmol/L)407 HbA1c≥6.5% (48 mmol/mol)203–– Total (%)433 (42.4)*414 (40.5)*Combined criteria FPG≥ 126 mg/dL (7.0 mmol/L)142≥126 mg/dL (7.0 mmol/L)142 OGTT 2-h PG≥ 200 mg/dL (11.1 mmol/L)288≥200 mg/dL (11.1 mmol/L)288 HbA1c≥ 6.5% (48 mmol/mol)203–– OGTT 1-h PG≥ 209 mg/dL (11.6 mmol/L)407≥209 mg/dL (11.6 mmol/L)407 Total (%)453 (44.4)*438 (43.9)**p<0.001 versus current criteria.ADA, American Diabetes Association; FPG, fasting plasma glucose; HbA1c, hemoglobin A1c; 1-h PG, 1-hour plasma glucose; 2-h PG, 2-hour plasma glucose; OGTT, oral glucose tolerance test; WHO, world health organization.We also found that the prevalence of DM using OGTT 1-h PG ≥209 mg/dL (11.6 mmol/L) as the cut-off was approximately 5.5% (56 people) when the OGTT 2-h PG was normal. However, using OGTT 2-h PG ≥200 mg/dL (11.1 mmol/L) yielded approximately 0.3% (3 people) when OGTT 1-h PG was normal.As table 3 showed, the prevalence of pre-diabetes was 24.4% (249 people) according to the current ADA standards and 21.8% (223 people) when the OGTT 1-h PG criterion was used. The prevalence of pre-diabetes was 20.8% (212 people) when the OGTT 1-h PG was added to the current ADA criteria. As for the conventional WHO criteria, the prevalence of pre-diabetes was 19.2% (196 people) and 21.8% (223 people) when the OGTT 1-h PG was used as the diagnostic standard. The pre-diabetes prevalence was 22.2% (227 people) when OGTT 1-h PG was added to the WHO criteria.Table 3Prevalence of pre-diabetes diagnosed by different diagnostic strategies based on ADA and WHO standardsDiagnostic strategyADA standardNWHO standardNCurrent criteria IFG (FPG)100–125 mg/dL (5.6–6.9 mmol/L)37110–125 mg/dL (6.1–6.9 mmol/L)24 IGT (OGTT 2-h PG)140–199 mg/dL (7.8–11.0 mmol/L)104140–199 mg/dL (7.8–11.0 mmol/L)172 HbA1c5.7–6.4% (39–46 mmol/mol)108–– Total (%)249 (24.4)196 (19.2)OGTT 1-h PG replacement IFG (FPG)100–125 mg/dL (5.6–6.9 mmol/L)15110–125 mg/dL (6.1–6.9 mmol/L)5 IGT (OGTT 1-h PG)155–207 mg/dL (8.6–11.5 mmol/L)138155–207 mg/dL (8.6–11.5 mmol/L)218 HbA1c (%)5.7–6.4% (39–46 mmol/mol)70–– Total (%)223 (21.8)*223 (21.8)*Combined Criteria IFG (FPG)100–125 mg/dL (5.6–6.9 mmol/L)13110–125 mg/dL (6.1–6.9 mmol/L)5 IGT (OGTT 2-h PG)140–199 mg/dL (7.8–11.0 mmol/L)63140–99 mg/dL (7.8–11.0 mmol/L)95 HbA1c5.7–6.4% (39–46 mmol/mol)62–– IGT (OGTT 1-h PG)155–207 mg/dL (8.6–11.5 mmol/L)125155–207 mg/dL (8.6–11.5 mmol/L)197 Total (%)212 (20.8)*227 (22.2)**p≥0.05 versus current criteria.ADA, American Diabetes Association; FPG, fasting plasma glucose; HbA1c, hemoglobin A1c; 1-h PG, 1-hour plasma glucose; 2-h PG, 2-hour plasma glucose; IFG, impaired fasting glucose; IGT, impaired glucose tolerance; OGTT, oral glucose tolerance test; WHO, world health organization.We further compared the consistency between the two diagnostic strategies (FPG, 1-h PG and HbA1c-based approach versus FPG, 2-h PG and HbA1c-based approach) for diabetes and pre-diabetes by Cohen’s Kappa test (tables 4–5). Substituting OGTT 1-h PG for OGTT 2-h PG in the ADA diagnostic strategy still retained good consistency for both diabetes (κ=0.7, 95% CI 70.1% to 78.4%, p<0.001) and pre-diabetes (κ=0.7, 95% CI 64.5% to 75.0%, p<0.001). Receiver operating characteristic curves (ROC curves) were constructed to compare the diagnostic performance between OGTT 1-h PG and OGTT 2-h PG. ADA criteria were used as the reference standard for diagnosing diabetes and pre-diabetes (online supplemental files 2 and 3). For diabetes, the area under the curves (AUC) was 93.7% (95% CI 92.2% to 95.1%) for OGTT 1-h PG and 96.1% (95% CI 94.7% to 97.3%) for OGTT 2-h PG. OGTT 1-h PG had a sensitivity of 87.3% (95% CI 83.6% to 90.7%) and a specificity of 83.8% (95% CI 81.0% to 86.7%), whereas OGTT 2-h PG achieved a sensitivity of 82.9% (95% CI 79.0% to 86.6%) with perfect specificity (100%). For pre-diabetes, the AUC was 71.8% (95% CI 67.9% to 75.8%) for OGTT 1-h PG and 70.4% (95% CI 65.9% to 74.5%) for OGTT 2-h PG, respectively. The corresponding sensitivity was 65.1% (95% CI 59.0% to 70.8%) vs 41.8% (95% CI 35.7% to 47.9%), while specificity was 68.0% (95% CI 63.4% to 72.7%) vs 88.5% (95% CI 85.2% to 91.6%).SP210.1136/bmjdrc-2025-005689.supp2Supplementary dataSP310.1136/bmjdrc-2025-005689.supp3Supplementary dataTable 4Consistency in diagnosis of diabetes between the OGTT 1-h PG and 2-h PG based on ADA diagnostic strategyOGTT 1-h PGκ95% CIP valueOGTT 2-h PGDiabetesNormal0.770.1% to 78.4%<0.001Diabetes32820Normal105568Kappa values (κ) were interpreted as follows: 0.81–1.00=very good, 0.61–0.80=good, 0.41–0.60=moderate, 0.21–0.40=fair, and <0.20 = poor.ADA, American Diabetes Association; 1-h PG, 1-hour plasma glucose; 2-h PG, 2-hour plasma glucose; OGTT, oral glucose tolerance test.Table 5Consistency in diagnosis of pre-diabetes between the OGTT 1-h PG and 2-h PG based on ADA diagnostic strategyOGTT 1-h PGκ95% CIP valueOGTT 2-h PGPre-diabetesNormal0.764.5% to 75.0%<0.001Pre-diabetes18168Normal42730ADA, American Diabetes Association ; 1-h PG, 1-hour plasma glucose; 2-h PG, 2-hour plasma glucose; OGTT, oral glucose tolerance test.Discussion Along with the economic development and population aging, the prevalence of diabetes is increasing globally. 14 Previous research indicated that OGTT 2-h PG was more repeatable than the OGTT 1-h PG and offered a more sensitive and specific status of the diabetes.15 16 Despite two revisions of the diagnosis criteria over the past few decades, international guidelines and expert consensus have consistently endorsed the OGTT 2-h PG as the standard diagnostic criterion for both diabetes and pre-diabetes. Individuals diagnosed with pre-diabetes by the OGTT 2-h PG may not progress to T2D through lifestyle intervention. However, using the OGTT 2-h PG only may cause late detection of pre-diabetes and miss the potential benefits of early intervention.3 A significant number of individuals at high risk of developing T2D remain undiagnosed.3 Pre-diabetes is related to elevated risk of cardiovascular disease and other complications.17 18 It is necessary to establish a more sensitive screening method to identify high-risk populations of diabetes. Recent research has consistently demonstrated that the OGTT 1-h PG is a more effective predictor of T2D and its complications than the OGTT 2-h PG, indicating its potential for earlier detection of diabetes and more accurate risk assessment.19–23T2D elevates the risk of macrovascular complications, such as ischemic heart disease, cerebrovascular disease, and peripheral vascular disease, as well as microvascular complications, including retinopathy, neuropathy, and nephropathy.24 At the time of initial diagnosis, some diabetes-related complications are often already present. These complications impose a significant socioeconomic burden and affect the quality of life adversely.25 Early diagnosis of diabetes could achieve earlier screening for complications and appropriate management, which reduces the mortality and disability rates associated with these complications. Our study discovered that diabetes prevalence increased markedly when we adopted the OGTT 1-h PG ≥209 mg/dL (11.6 mmol/L) as the diagnostic criterion, which was consistent with those of other studies in high-risk groups. Studies in Thai high-risk individuals showed that diabetes prevalence more than doubled when IDF criteria were applied (35.1% vs 16.8%), while a longitudinal Korean cohort confirmed that normal glucose tolerance (NGT) with elevated 1-h PG (≥155 mg/dL) represents an intermediate risk state with significantly higher T2D risk (HR 3.9) and earlier disease progression by 0.9 year compared with low 1-h PG NGT.26 27 Gupta et al also found that pregnant women with a history of gestational diabetes and a 1-h PG at or above 209 mg/dL (11.6 mmol/L) were much more likely to develop diabetes after delivery.10 This consistency across different populations strengthens the evidence that the elevated 1-h PG is effective in identifying individuals at high risk of diabetes. Additionally, our study also demonstrated that adoption of OGTT 1-h PG ≥209 mg/dL (11.6 mmol/L) as an additional criterion markedly increased the prevalence of diabetes. When OGTT 2-h PG is within the normal range, the prevalence of diabetes, diagnosed with OGTT 1-h PG ≥209 mg/dL (11.6 mmol/L), stands at 5%. Conversely, when OGTT 1-h PG is normal, the prevalence of diabetes diagnosed with OGTT 2-h PG ≥200 mg/dL (11.1 mmol/L) is 0.3%. Collectively, these data demonstrate that OGTT 1-h PG is more sensitive than OGTT 2-h PG for diabetes diagnosis.More importantly, 1-h PG is more sensitive than 2-h PG in reflecting early β-cell dysfunction, which enables it to identify high-risk individuals before they progress to IGT.28 Therefore, OGTT 1-h PG is of great significance for early screening of abnormal glucose metabolism. Additionally, the practical feasibility and cost-effectiveness of OGTT 1-h PG in clinical practice also make it a convenient option. In low-income countries, HbA1c is less accessible; blood glucose testing remains a more feasible option. 1-h PG is a simple and repeatable one. As table 4 showed, we found that replacing OGTT 2-h PG with OGTT 1-h PG under the ADA diagnostic standard still retained good consistency for diabetes (κ=0.7, 95% CI 70.1% to 78.4% p<0.001). The AUC of two methods were similar for diagnosis of diabetes (1-h PG 93.7%, SE: 87.3%, Sp: 83.8% vs 2-h PG 96.1%, SE: 82.9%, Sp: 100%) (online supplemental figure 2). Consequently, we concluded that the 1-h PG criterion can identify largely the same individuals as the traditional 2-h PG criterion. OGTT 1-h PG may be a more appropriate diagnostic criterion for diabetes.As mentioned above, the OGTT 1 h PG is more sensitive for diabetes diagnosis but does not add value for pre-diabetes. Previous observational studies have shown that OGTT 1-h PG≥155 mg/dL (8.6 mmol/L) was directly related to the occurrence of T2D, and this association was more pronounced than FPG or OGTT 2-h PG.9 An elevated 1-h PG is not only closely related to the onset of diabetes, but also significantly associated with diabetic complications (such as retinopathy and cardiovascular disease) and mortality.29 30 Previous study have shown that individuals with 1 hour impaired glucose tolerance have a significantly increased incidence rate of diabetes.20 As the table 5 showed, we found that using OGTT 1-h PG as pre-diabetes diagnostic standard under the ADA diagnostic criteria also retained good consistency (κ=0.7, 95% CI 64.5% to 75.0%, p<0.001). The AUC of two methods were similar for diagnosis of pre-diabetes (1-h PG 71.8%, Se: 65.1%, Sp: 68.0% vs 2 h PG 70.4%, Se: 41.8%, Sp: 88.5%) (online supplemental figure 3). Our study also found that there was no statistical significance in the prevalence of pre-diabetes when using OGTT 1-h PG ≥155 mg/dL (8.6 mmol/L) instead of OGTT 2-h PG ≥140 mg/dL (7.8 mmol/L).Taken together, our results indicated that OGTT 1-h PG offers superior sensitivity for diabetes diagnosis, facilitating earlier detection of high-risk individuals. Although increased 1-h PG is an important predictor of diabetes development, taking 1-h PG as the screening standard may cause some concerns. It may lead to repeated screening, increase unnecessary costs, and may bring a sharp increase in the prevalence of diabetes which will place great pressure on the healthcare system.Conclusion The prevalence of diabetes was significantly higher when the OGTT 1-h PG was adopted according to the ADA and WHO diagnostic standards. More patients with diabetes will be identified early and treated promptly. Meanwhile, this will place a heavy burden on the global healthcare system. The OGTT 1-h PG may become a promising diagnostic criterion for diabetes and pre-diabetes in the future, but more prospective studies are needed to validate its clinical utility before that.Limitation Our study was a single-center, retrospective study with participants recruited from the endocrinology clinic of one hospital; it is susceptible to significant selection bias, and the conclusion is limited and may not be generalized. Moreover, longitudinal follow-up assessment of how OGTT 1-h PG predicts future diabetes development and complications is lacking. Furthermore, our findings require validation in diverse ethnic populations and healthcare institutions.",
  "title": "Feasibility of using OGTT 1-h PG as a diagnostic criterion for diabetes and pre-diabetes",
  "uid": "f07efdb8-d2fa-5313-a94c-3d668fd35f6c"
}