Journal of the ASEAN Federation of Endocrine Societies

Characteristics and Prevalence of Metabolic Syndrome among Adult Filipinos with Hypothyroidism

Sun, 04 Feb 2024 00:00:00 -0800

Objectives. We determined the clinical characteristics and prevalence of metabolic syndrome among adult Filipinos with overt hypothyroidism.

Methodology. This is a cross-sectional study of 151 adults. Patients were recruited by sequential enrollment. Anthropometric and blood pressure measurements were performed followed by blood extraction for metabolic parameters and thyroid function tests. Clinical and laboratory characteristics were compared between patients with and without metabolic syndrome.

Results. The prevalence of metabolic syndrome is 40.4% (95%CI: 32.5%, 48.7%). Patients with metabolic syndrome have a waist circumference of 88.4 ± 7.7 cm in females and 93.3 ± 9.0 cm in males. The median fasting blood glucose was 111.4 (52.2) mg/dL, median systolic blood pressure of 120 (30) mm Hg and diastolic blood pressure of 80 (20) mmHg, median serum triglycerides of 174.3 (114.2) mg/dL, median HDL-C of 42.3 (19.2) mg/dL and a proportion of patients with diabetes (23.0%) and hypertension (44.3%), respectively. The presence of increased waist circumference is the most prevalent component seen among hypothyroid patients. There were no differences in terms of age, sex, etiology of hypothyroidism and anti-TPO levels in those with and without metabolic syndrome.

Conclusion. The prevalence of metabolic syndrome in adult Filipinos with hypothyroidism is high. Emphasis must be placed on early screening using waist circumference and metabolic parameters among hypothyroid patients who are at high risk of developing metabolic syndrome.

Fructosamine and HbA1c

Kurumbian Chandran, See Muah Lee, Liang Shen, Eng Loon Tng — Thu, 08 Feb 2024 00:00:00 -0800

Objectives. Fructosamine correlates well with glycated haemoglobin (HbA1c) in Caucasians. This study investigates this correlation and whether fructosamine can reliably estimate glycated haemoglobin in Southeast Asians.

Methodology. We recruited 193 participants based on 4 HbA1c bands (<6.0%; 6.0 – 7.9%; 8.0– 9.9%; ≥10%) from a secondary hospital in Singapore between August 2017 and December 2021. Blood samples for fructosamine, glycated haemoglobin, albumin, haemoglobin, thyroid stimulating hormone and creatinine were drawn in a single setting for all participants. Scatter plot was used to explore correlation between fructosamine and glycated haemoglobin. Strength of linear correlation was reported using Pearson’s correlation coefficient. Simple linear regression was used to examine the relationship between fructosamine and glycated haemoglobin.

Results. We performed simple linear regression to study the relationship between fructosamine and HbA1c in the research participants (R²= 0.756, p<0.01). Further analysis with natural logarithmic transformation of fructosamine demonstrated a stronger correlation between HbA1c and fructosamine (R²= 0.792, p<0.01).

Conclusions. Fructosamine is reliably correlated with HbA1c for the monitoring of glycaemic control in Southeast Asians.

The Acute Coronary Syndrome Risk in Medically Managed Subjects with Type 2 Diabetes Mellitus

Ameya Joshi, Harminder Singh, Sanjay Kalra — Mon, 05 Feb 2024 00:00:00 -0800

Objectives. The risk of acute coronary syndrome (ACS) is high in subjects with type 2 diabetes mellitus (T2DM). The current management algorithm focuses on atherosclerotic cardiovascular (ASCVD) risk score to stratify this risk. However, in medically managed subjects, this algorithm may not be accurate. The current study compares the ASCVD risk score calculated in a subset of the Indian population with T2DM under medical supervision and the actual incidence of ACS. It also compared the ASCVD risk scores in cases with T2DM who developed ACS to controls who did not and tried to estimate whether the ASCVD risk score is different in the two subsets, thereby evaluating the utility of ASCVD risk score in predicting ACS in subjects with T2DM on medical management. The impact of other factors like hypertension, dyslipidaemia, family history of ACS, and duration of T2DM on the development of ACS was also investigated.
Methodology. This is an electronic medical record (EMR) based case-control study. Only records of subjects with T2DM where details of age, sex, body mass index, blood pressure, duration of diabetes, family history of ACS, lipid profile, renal and liver function tests (in those affected with ACS, the details need to be within 6 months prior to the ACS) were included. The incidence of ACS was calculated in the selected records. The records of subjects who developed ACS were compared with age and sex-matched subjects who did not develop ACS. Data are summarized as median and interquartile range (IQR). Wilcoxon rank-sum test was used for checking differences in continuous variables and Pearson’s Chi-squared test for categorical data. Univariate and multivariate logistic regression analyses were used to check the effect of ASCVD scores and other variables on the occurrence of ACS.
Statistical data analyses were performed using JASP, version 0.16.4 (JASP Team [2022]) for MS Windows.
Results. Of the 1226 EMRs included in the analysis, 207 had ACS. The actual incidence of ACS was 16.85 percent in 6 years which was more than the mean predicted 10-year incidence of 14.56 percent (p <0.05). The cases were age and sex-matched with controls and the ASCVD incidence was estimated in the two groups. The mean ASCVD score in the cases was 14.565 ± 8.709 (Min: 1.5, Max: 38.3) and controls 13.114 ± 8.247 (Min: 1.4, Max: 45). We conclude that the ASCVD risk score may not accurately predict the ACS risk (may underestimate) and may be similar in those who developed ACS and those who did not. The chance of development of ACS increases with raised systolic blood pressure (per mmHg rise OR: 1.04, 95% CI: 1.03, 1.06; p <0.001), positive family history (OR: 5.70, 95% CI: 3.41, 9.77; p <0.001), statin use (OR: 2.26, 95% CI: 1.46, 3.52; p <0.001), and longer duration of diabetes (for every year increase OR: 1.19, 95% CI: 1.13, 1.25; p <0.001)
Conclusion. The authors conclude that the ASCVD risk score underestimates the ACS risk in subjects with T2DM under medical supervision and may not be different in those who developed and those who did not develop ACS. We also conclude that factors like family history (30% less risk with negative family history), longer duration of diabetes, and higher SBP may be of relevance in those who developed ACS and throw open the need for more objective measures to assess risk in T2DM under medical supervision.

Prevailing Food Intake, Physical Activity and Health Beliefs in a Rural Agricultural Community in the Philippines

Wed, 06 Dec 2023 00:00:00 -0800

Objective. A diabetes prevention program is being proposed in the rural agricultural town of San Juan, Batangas, Philippines. This study aims to determine the prevailing level of food intake, physical activity, and health beliefs prior to any intervention.

Methodology. Adults were recruited via random sampling with proportional allocation. Interviews were done to determine food intake and physical activity. Small group discussions were held to determine prevailing health beliefs.

Results. The average energy intake (1,547 kcal/d) is only 72% of the recommended values for Filipinos. Only 12% of the respondents achieved the recommended energy intake. Carbohydrates comprise a large part (71%) of calorie intake. A majority (91%) already have moderate to high levels of physical activity. There are prevailing health beliefs that need to be considered when dietary modifications and physical activity interventions are to be done.

Conclusion. Internationally recommended diabetes prevention interventions such as reducing calorie intake and increasing physical activity may not be directly applicable here. We recommend that the features of a diabetes prevention program for this locale must include the following: 1) introduction of affordable plant sources of proteins; 2) decreasing the proportion of rice as a source of carbohydrates in the diet; 3) maintaining the level of physical activity; and 4) being sensitive to the prevailing health beliefs.

Diagnostic Accuracy of American College of Radiology Thyroid Imaging Reporting Data System

Mon, 08 Jan 2024 00:00:00 -0800

Objective. This study aims to evaluate the diagnostic accuracy of the American College of Radiology Thyroid Imaging Reporting Data System (ACR TI-RADS) in identifying nodules that need to undergo fine-needle aspiration biopsy (FNAB) and identify specific thyroid ultrasound characteristics of nodules associated with thyroid malignancy in Filipinos in a single tertiary center.

Methodology. One hundred seventy-six thyroid nodules from 130 patients who underwent FNAB from January 2018 to December 2018 were included. The sonographic features were described and scored using the ACR TI-RADS risk classification system, and the score was correlated to their final cytopathology results.

Results. The calculated malignancy rates for TI-RADS 2 to TI-RADS 5 were 0%, 3.13%, 7.14%, and 38.23%, respectively, which were within the TI-RADS risk stratification thresholds. The ACR TI-RADS had a sensitivity of 89.5% and specificity of 54%, LR + of 1.95 and LR - of 0.194, NPV of 97.7%, PPV of 19.1%, and accuracy of 58%.

Conclusion. The ACR TI-RADS may provide an effective malignancy risk stratification for thyroid nodules and may help guide the decision for FNAB among Filipino patients. The classification system may decrease the number of unnecessary FNABs for nodules with low-risk scores.

Age and Sex-Related Chromogranin A Gene Polymorphisms and its Association with Metabolic Syndrome Components

Abdoljalal Marjani, Nahid Poursharifi, Atefe Sajedi, Mahin Tatari — Wed, 10 Jan 2024 00:00:00 -0800

Introduction. The purpose of this study was to determine the possible differences in genetic polymorphisms and serum levels of chromogranin A (CgA), according to age and sex, in subjects with and without metabolic syndrome (MetS).

Methodology. The genotyping and serum level of CgA and biochemical parameters were measured by the T-ARMS-PCR and PCR-RFLP and ELISA and spectrophotometer methods, respectively.

Results. A comparison of males with and without MetS showed significantly lower high-density lipoprotein-cholesterol (HDL-C) levels than those of females.

At ages 30-70 years, both sexes showed significant differences in triglycerides (TG), fasting blood sugar (FBS), CgA levels and waist circumference (WC) when compared to the two groups. Both sexes with MetS indicated significant differences in systolic blood pressure (SBP) at ages 40-70 years, while at ages 40-59 years, there was a significant difference in HDL-C level in males.

There was a significant correlation between serum levels of FBS, TG, SBP and WC (in both sexes), and CgA in subjects with MetS. Significant correlation was found between HDL-C level and diastolic blood pressure (DBP), and CgA level in males and females, respectively. CgA genotype frequency (T-415C and C+87T polymorphisms) showed no significant differences between males and females with and without MetS, while there was only a significant difference in frequency of the genotypes T-415C when compared to males with and without MetS.

Conclusion. The CgA appears to be strongly associated with MetS components in both sexes. Variation in CgA gene expression may affect the T–415C polymorphism in males. This may mean that the structure of CgA genetics differs in different ethnic groups. Differences in the serum level and expression of CgA gene may show valuable study results that it may be expected a relationship between these variables and the MetS.

Early Puberty Trend during the COVID-19 Pandemic in Singapore

Annie Leong, Rashida Farhad Vasanwala — Thu, 11 Jan 2024 00:00:00 -0800

Objectives. We aimed to study the trend of referrals for precocious puberty during the COVID-19 pandemic compared to pre-COVID years, explore the differences in the demographic and clinical features, and evaluate the contributing factors.

Methodology. The cases referred for assessment of PP from 2018-2021 to our endocrine centre were grouped into pre-COVID (2018-2019) and COVID (2020-2021) years. Cases fulfilling the diagnosis of PP included the onset of thelarche <8 years in females and 4mls testicular volume <9 years in males. The PP was further differentiated as Isolated Thelarche (IST) and Central Precocious Puberty (CPP). Early menarche was defined as menarche <10 years old.

Results. There were more referrals for PP and more diagnosed as CPP during the COVID-19 pandemic, predominantly among females. There were more endocrine tests done and more cases received treatment. None of the abnormal magnetic resonance imaging (MRI) pituitary findings required surgical intervention. The body mass index (BMI) was found to be positively associated with the risk of getting CPP with a crude-odd ratio (COR) of 1.8, P <0.001, and early menarche (COR 2.1, P <0.001).

Conclusion. We found a significant increase in the referrals of PP and diagnosis of CPP during the COVID-19 pandemic. Higher BMI was found to be associated with CPP and early menarche.

Validation of the Gestational Diabetes Mellitus Knowledge Questionnaire (GDMKQ) among Filipino Patients in a Tertiary Medical Center

Hanah Go, Florence Rochelle Gan — Wed, 06 Dec 2023 00:00:00 -0800

Objectives. Gestational diabetes mellitus (GDM) is a common pregnancy complication with adverse fetal and maternal outcomes. Currently, there are only a few validated tools available that address knowledge in GDM. Recognition of the inconsistencies will provide for an effective learning program to achieve optimal results. This study aimed at validating the “Gestational Diabetes Mellitus Knowledge Questionnaire” (GDMKQ).

Methodology. A cross-sectional validation study on GDMKQ among 51 GDM patients aged at least 18 years was conducted in the outpatient clinics of a tertiary hospital. Excluded were those with pre-existing diabetes. The questionnaire was submitted for peer review for translation to Filipino and back-translation. Concurrent validity, internal consistency and test-retest reliability of the questionnaire were undertaken as part of the validation process. Descriptive analysis was used for data elaboration by using SPSS v23.

Results. The Filipino version of GDMKQ demonstrated sensible content and face validity. As measured, respondents obtained higher total and domain scores with better knowledge levels of GDM compared to its English version. An overall adequate knowledge was observed among those married and college subgroup as compared to single women and those with secondary level of education. The reliability of the questionnaire was calculated at 0.632 using the Kuder-Richardson 20. The test-retest scores using the Filipino-translated questionnaire has a Pearson correlation coefficient of 0.853 with moderate to good level of agreement with each other, and Cohen’s kappa of 0.564 with an intra-class correlation coefficient of 0.828.

Conclusion. The Filipino-translated version of GDMKQ is a valid screening tool that assesses a patient’s knowledge of gestational diabetes. Identifying the level of their understanding will enable clinicians to develop an individualized, effective learning program to improve pregnancy outcomes.

Endocrine Disorders in Childhood Brain Tumour Survivors

Nurul Wahidah Ramezan, Suhaimi Hussain, Norsarwany Mohamad, Najib Majdi Yaacob — Fri, 22 Dec 2023 00:00:00 -0800

Objective: The study aims to determine the prevalence and risk factors for endocrine disorders in childhood brain tumour survivors.

Methodology: 124 childhood brain tumour survivors aged 18 years old or younger with either stable disease or in remission, and had survived for at least 2 years after diagnosis were included in the study. Demographic data (age at diagnosis, gender, ethnicity, socioeconomic status), clinical clues for endocrine disorders, anthropometrics (weight, height, midparental height), pubertal staging, tumour-related characteristics, treatment modalities and endocrine laboratory measurements at diagnosis and during follow up were obtained. Logistic regression was applied to evaluate risk factors for endocrine disorders in childhood brain tumour survivors.

Results: The prevalence of endocrine disorders in childhood brain tumour survivors was 62.1%. The risk factors were high BMI [adjusted odds ratio (OR) 1.29, 95% CI: 1.12 to 1.5], high-risk site [adjusted odds ratio (OR) 7.15, 95% CI: 1.41 to 36.3] and chemotherapy [adjusted odds ratio (OR) 0.18 , 95% CI: 0.05 to 0.62].

Conclusion: The prevalence of endocrine disorders in childhood brain tumour survivors in our centre was 62.1%. The significant risk factors were high BMI, tumour location (suprasellar and intrasellar) and chemotherapy.

Manifestations of Hypothyroidism in Infants with Maternal Graves' Disease

Fri, 05 Jan 2024 00:00:00 -0800

Infants of mothers with Graves’ disease (GD) may develop central hypothyroidism (CH) due to exposure of the foetal hypothalamic-pituitary-thyroid axis to higher-than-normal thyroid hormone concentrations, primary hypothyroidism (PH) due to transplacental passage of maternal thyroid stimulating hormone receptor antibody (TRAb), antithyroid drugs (ATD) or thyroid dysgenesis secondary to maternal uncontrolled hyperthyroidism. We describe two infants with PH and four infants with CH born to mothers with poorly controlled Graves' disease. All infants required levothyroxine and had normal developmental milestones. While national guideline consensus for high thyroid stimulating hormone (TSH) on neonatal screening is well-established, thyroid function tests (TFTs) should be serially monitored in infants with low TSH on screening, as not all mothers with Graves’ disease are diagnosed antenatally.

Primary Hyperparathyroidism during Pregnancy

Yoon Doong Loh, Masliza Hanuni Mohd Ali — Thu, 08 Feb 2024 00:00:00 -0800

Primary hyperparathyroidism (PHPT) is rare in pregnancy. This condition is challenging to diagnose and manage due to the limited diagnostic and therapeutic options that are safe during pregnancy. If not diagnosed and managed in a timely manner, serious maternal and foetal complications may occur. We report two cases, one with surgical intervention and one without, to show the importance of timely surgical intervention and discuss the challenges in the management of PHPT in pregnancy.

Interrelationship of Sarcopenia and Cardiovascular Diseases

Fri, 27 Oct 2023 00:00:00 -0700

Sarcopenia refers to an age-related reduction of lean body mass. It showed a reciprocal relationship with cardiovascular diseases. Thus, it is imperative to explore pathophysiological mechanisms explaining the relationship between sarcopenia and cardiovascular diseases, along with the clinical assessment, and associated management. In this review, we discuss how processes such as inflammation, oxidative stress, endothelial dysfunction, neural and hormonal modifications, as well as other metabolic disturbances influence sarcopenia as well as its association with cardiovascular diseases. Moreover, this review provides an overview of both non-pharmacological and pharmacological management for patients with sarcopenia and cardiovascular diseases, with a focus on the potential role of cardiovascular drugs to mitigate sarcopenia.

Effects of Combination of Curcumin and Piperine Supplementation on Glycemic Profile in Patients with Prediabetes and Type 2 Diabetes Mellitus

Sat, 17 Feb 2024 00:00:00 -0800

Objective. This study aimed to evaluate the effects of combination of curcumin and piperine supplementation on Fasting Plasma Glucose (FPG), Homeostatic Model of Insulin Resistance (HOMA-IR), Body Mass Index (BMI) in patients with prediabetes and type 2 Diabetes Mellitus (T2DM). This review was done to identify potential herbal remedies that may help improve glycemic parameters, leading to better health outcomes in combination with current antidiabetic treatment.

Methodology. This systematic review was based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). It was conducted in 2023 with sources and databases from MEDLINE, EBSCO-Host, ScienceDirect and ProQuest. This paper included randomized-controlled trials exploring the effects of the combination of curcumin and piperine on patients with prediabetes and T2DM. Systematic reviews, observational studies, case reports, case series, conference abstracts, book sections, commentaries/editorials, non-human studies and articles with unavailable full-text and written in non-English language, were excluded. The key terms for the literature search were “curcumin,” “piperine,” “prediabetes” and “Type 2 Diabetes Mellitus.” We use Cochrane Risk of Bias (RoB) 2 for quality assessment of the included studies and Review Manager (RevMan) 5.4 to do the meta-analysis.

Results. A total of three studies were included in this systematic review. Two studies from Neta et al., and Cicero et al., showed no significant difference in HOMA-IR, BMI and FPG levels between the curcumin, piperine and placebo groups. One study from Panahi et al. demonstrated a significant difference in BMI levels between the curcumin and piperine and placebo groups (p <0.01). The meta-analysis showed that FPG levels, HOMA-IR and BMI improved among patients with diabetes given in curcumin and piperine with reported mean differences (MD) of = -7.61, 95% CI [-15.26, 0.03], p = 0.05, MD = -0.36, 95% CI [-0.77 to 0.05], p = 0.09, and MD = -0.41, 95% CI [-0.85 to 0.03], p = 0.07, respectively).

Conclusions. The supplementation of curcumin and piperine showed a numerical reduction in FPG, HOMA-IR and BMI, but were not statistically significant. Further research is needed as there is a paucity of studies included in the review.

The Roles of Non-Pharmacologic and Emerging Pharmacologic Management of Non-alcoholic Fatty Liver Disease and Sarcopenia

Fri, 27 Oct 2023 00:00:00 -0700

Non-alcoholic fatty liver disease (NAFLD) is one of the most prevalent causes of chronic liver disease worldwide which is often seen in patients with metabolic abnormalities such as those with obesity and insulin resistance. On the other
hand, sarcopenia is a generalized and progressive skeletal muscle disorder characterized by low muscle strength, low muscle quality, low physical performance, or a combination of the three. Both disease entities share several underlying risk factors and pathophysiologic mechanisms. These include: (1) cardiometabolic overlaps such as insulin resistance, chronic systemic inflammation, decreased vitamin D levels, sex hormone modifications; (2) muscle-related factors such as those mitigated by myostatin signaling, and myokines (i.e., irisin); and (3) liver-dysfunction related factors such as
those associated with growth hormone/insulin-like growth factor 1 Axis, hepatokines (i.e., selenoprotein P and leukocyte cell-derived chemotaxin-2), fibroblast growth factors 21 and 19 (FGF21 and FGF19), and hyperammonemia. This narrative review will examine the pathophysiologic overlaps that can explain the links between NAFLD and sarcopenia. Furthermore, this review will explore the emerging roles of nonpharmacologic (e.g., weight reduction, diet, alcohol, and smoking cessation, and physical activity) and pharmacologic management (e.g., roles of β-hydroxy-β-methylbutyrate, branched-chain amino acid supplements, and testosterone therapy) to improve care, intervention sustainability, and acceptability for patients with sarcopenia-associated NAFLD.

Efficacy and Safety of Bromocriptine-QR as an Adjunctive Therapy on Glycemic Control in Subjects with Uncontrolled Type 2 Diabetes Mellitus

Wed, 21 Feb 2024 00:00:00 -0800

Introduction. There has been an increasing awareness of the effects of combining bromocriptine-QR with other medications for diabetes mellitus type 2. This study aimed to assess the efficacy and safety of bromocriptine-QR as an adjunctive therapy for patients with uncontrolled type 2 diabetes mellitus.

Methodology. This systematic review is registered at the International Prospective Register of Systematic Reviews (CRD42022360326). Literature search was done via MEDLINE, NCBI, Google Scholar, Science Direct, Europe PMC and Cochrane Library databases. We included randomized controlled trials with participants 18 years old and above with uncontrolled type 2 diabetes mellitus. The primary outcome of interest is the efficacy and safety of bromocriptine-QR as an adjunctive therapy for glycemic control. Case reports, case series, reviews and animal studies were excluded. The risk of bias was reviewed using the Cochrane Risk of Bias tool. Meta-analysis was performed using Review Manager 5.4 and presented as a weighted mean difference and 95% confidence interval for changes from the baseline level.

Results. Nine studies were included in the systematic review with a total of 2709 participants. The baseline HbA1c in the bromocriptine-QR group was 7.42% and 7.51% in the control group. The bromocriptine-QR group was favoured, outperforming the control group in terms of reducing hemoglobin A1c(HbA1c), with a statistically significant difference (weighted mean difference -0.6%; 95% CI [-0.83,-0.36]; p<0.00001). The most common side effects were nausea (33.75% vs 6.92%), fatigue (13.11% vs 5.94%), and headache (11.17% vs 6.87%).

Conclusion. Administration of bromocriptine-QR at a dose range of 1.6 to 4.8 mg/day as an adjunctive therapy reduced HbA1c and FBG in patients with uncontrolled type 2 diabetes mellitus (T2DM). However, there were also statistically greater odds of the occurrence of adverse events such as nausea, vomiting, and headache compared to controls.

Insulin Autoimmune Syndrome – An After-Meal Roller Coaster Ride

Chee Koon Low, Hui Chin Wong, Saraswathy Apparow, Sy Liang Yong — Thu, 11 Jan 2024 00:00:00 -0800

Hypoglycemic disorders are rare in persons without diabetes, and clinical evaluation to identify its etiology can be challenging. We present a case of insulin autoimmune syndrome induced by carbimazole in a middle-aged Chinese man with underlying Graves’ disease, which was managed conservatively with a combination of dietary modification and alpha-glucosidase inhibitor.

A Systematic Review of the Accuracy of Insulin and C-peptide Secretion Ratios During the Oral Glucose Tolerance Test to Diagnose Insulinoma

Fransiskus Mikael Chandra, Dicky Tahapary — Mon, 05 Feb 2024 00:00:00 -0800

Background. Insulinoma is one of the causes of recurrent hypoglycemia, one of the chief complaints for emergency department admission. The gold standard in diagnosing insulinoma is a 72-hour fasting test which is inconvenient and inefficient as it requires hospitalization. Research has found that measurement of insulin and C-peptide during OGTT may help diagnose insulinoma. We aimed to assess the diagnostic value of OGTT in diagnosing insulinoma.

Methodology. The literature search was conducted on 19 August 2022 using several databases (MEDLINE, Scopus, Embase, and ScienceDirect). All studies that measured OGTT as diagnostic tools in diagnosing insulinoma and 72-hour fasting test as reference standard were included. The quality assessment of the selected studies was based on the Centre of Evidence-Based Medicine University of Oxford and the Quality Assessment of Diagnostic Accuracy-2 tool (QUADAS-2). Analysis of the included studies was performed qualitatively. This study was registered on PROSPERO (CRD42022360205).

Results. A total of two case-control studies (106 patients) were included, which were at risk of bias and low concern of applicability. Both studies demonstrated that the combination of insulin and C-peptide levels measured during OGTT had high specificity, sensitivity, positive predictive value, and negative predictive value in diagnosing insulinoma compared to the reference standard. A logistic regression model of 8.305 – (0.441 × insulin 2-h/0-h) – (1.679 × C-peptide 1-h/0-h) > 0.351 has the highest diagnostic value in one study (AUC 0.97, Sensitivity 86.5%, Specificity 95.2%, PPV 94.1, NPV 88.9).

Conclusion. The measurement of 0-h and 2-h insulin and C-peptide levels during 2-h OGTT was found in two small case-control studies with a total of 106 patients to have good sensitivity and specificity. However, due to these limitations, future research is still needed to validate the potential use of OGTT for the diagnosis of insulinoma.