Faculty Bibliography

Many individuals with intermediate hyperglycaemia (IH), including impaired fasting glycaemia (IFG) and impaired glucose tolerance (IGT), as presently defined, will progress to type 2 diabetes (T2D). There is confirmatory evidence that T2D can be prevented by lifestyle modification and/or medications, in people with IGT diagnosed by 2-h plasma glucose (PG) during a 75-gram oral glucose tolerance test (OGTT). Over the last 40 years, a wealth of epidemiological data has confirmed the superior value of 1-h plasma glucose (PG) over fasting PG (FPG), glycated haemoglobin (HbA_1c) and 2-h PG in populations of different ethnicity, sex and age in predicting diabetes and associated complications including death. Given the relentlessly rising prevalence of diabetes, a more sensitive, practical method is needed to detect people with IH and T2D for early prevention or treatment in the often lengthy trajectory to T2D and its complications. The International Diabetes Federation (IDF) Position Statement reviews findings that the 1-h post-load PG ≥ 155 mg/dL (8.6 mmol/L) in people with normal glucose tolerance (NGT) during an OGTT is highly predictive for detecting progression to T2D, micro- and macrovascular complications, obstructive sleep apnoea, cystic fibrosis-related diabetes mellitus, metabolic dysfunction-associated steatotic liver disease, and mortality in individuals with risk factors. The 1-h PG of 209 mg/dL (11.6 mmol/L) is also diagnostic of T2D. Importantly, the 1-h PG cut points for diagnosing IH and T2D can be detected earlier than the recommended 2-h PG thresholds. Taken together, the 1-h PG provides an opportunity to avoid misclassification of glycaemic status if FPG or HbA_1c alone are used. The 1-h PG also allows early detection of high-risk people for intervention to prevent progression to T2D which will benefit the sizeable and growing population of individuals at increased risk of T2D. Using a 1-h OGTT, subsequent to screening with a non-laboratory diabetes risk tool, and intervening early will favourably impact the global diabetes epidemic. Health services should consider developing a policy for screening for IH based on local human and technical resources. People with a 1-h PG ≥ 155 mg/dL (8.6 mmol/L) are considered to have IH and should be prescribed lifestyle intervention and referred to a diabetes prevention program. People with a 1-h PG ≥ 209 mg/dL (11.6 mmol/L) are considered to have T2D and should have a repeat test to confirm the diagnosis of T2D and then referred for further evaluation and treatment. The substantive data presented in the Position Statement provides strong evidence for redefining current diagnostic criteria for IH and T2D by adding the 1-h PG.

Objective: HbA1c is an insensitive marker for assessing real-time dysglycemia in obesity. This study investigated whether 1-h plasma glucose level (1-h PG) ≥155 mg/dL (8.6 mmol/L) during an oral glucose tolerance test (OGTT) and continuous glucose monitoring (CGM) measurement of glucose variability (GV) better reflected dysglycemia than HbA1c after weight loss from metabolic and bariatric surgery. Methods: This was a prospective cohort study of 10 participants with type 2 diabetes compared with 11 participants with non-diabetes undergoing sleeve gastrectomy (SG). At each research visit; before SG, and 6 weeks and 6 months post-SG, body weight, fasting lipid levels, and PG and insulin concentrations during an OGTT were analyzed. Mean amplitude of glycemic excursions (MAGE), a CGM-derived GV index, was analyzed. Results: The 1-h PG correlated with insulin resistance markers, triglyceride/HDL ratio and triglyceride glucose index in both groups before surgery. At 6 months, SG caused 22% weight loss in both groups. Despite a reduction in HbA1c by 3.0 ± 1.3% in the diabetes group (p < 0.01), 1-h PG, and MAGE remained elevated, and the oral disposition index, which represents pancreatic β-cell function, remained reduced in the diabetes group when compared to the non-diabetes group. Conclusions: Elevation of GV markers and reduced disposition index following SG-induced weight loss in the diabetes group underscores persistent β-cell dysfunction and the potential residual risk of diabetes complications.

BACKGROUND/OBJECTIVE/UNASSIGNED:To report a case of recalcitrant post-surgical hypocalcemia caused by hypoparathyroidism complicated by a chyle leak and octreotide use. CASE REPORT/UNASSIGNED:A man in his 60s with a 4-month history of voice changes, 10-pound weight loss, and a right-sided neck mass presented with difficulty breathing for 1 week. He had a right laryngeal/hypopharyngeal mass, which was biopsied. Pathology results were positive for invasive squamous cell carcinoma. He underwent an extensive neck surgery, including total thyroidectomy. Postsurgical laboratory results revealed serum corrected calcium of 7.6 mg/dL (ref 8.0-10.2 mg/dL) and parathyroid hormone <6.3 pg/mL (ref. 10-65). Despite treatment with calcium carbonate 12 g (elemental) daily, calcitriol and hydrochlorothiazide, his corrected serum calcium levels remained low. Patient also had a chyle leak that was treated with octreotide. Resolution of his hypocalcemia occurred after substitution of calcium carbonate with calcium citrate, cessation of octreotide, and management of the chyle leak. DISCUSSION/UNASSIGNED:Our patient likely developed recalcitrant hypocalcemia from: 1) postsurgical hypoparathyroidism, 2) a chyle leak, and 3) the use of octreotide. Administration of octreotide to seal the chyle leak most likely decreased gastric acid production and contributed to decrease in absorption of calcium carbonate. Oral calcium citrate may be better absorbed in this case. CONCLUSION/UNASSIGNED:Postsurgical hypoparathyroidism can lead to hypocalcemia. This case is unique in that the patient's chyle leak and the use of octreotide contributed to recalcitrant hypocalcemia.

INTRODUCTION/BACKGROUND:Sodium-glucose cotransporter-2 [SGLT2] inhibitors reduce cardiovascular events and mortality in patients with diabetes, particularly patients with established cardiovascular disease. Euglycemic diabetic ketoacidosis [euDKA], a complication of SGLT2 therapy, can be exacerbated by a low carbohydrate diet. CASE REPORT/METHODS:A 61-year-old man with a history of type 2 diabetes, taking a SGLT2 inhibitor empagliflozin 10 mg orally daily, presented to the emergency room with a 2-day history of nausea and chest pain. A week prior to presentation, he had started a ketogenic diet. He was initially admitted with a diagnosis of acute coronary syndrome. On initial assessment in the emergency room, his cardiac enzymes were normal and there were no ischemic changes in his ECG. As there was concern for unstable angina, he underwent cardiac catheterization, which showed a known total occlusion with collaterals and arteries with non-obstructive disease without evidence of acute plaque rupture. His baseline laboratory assessments revealed an elevated anion gap of 17, increased urinary and plasma ketones, and metabolic acidosis. His plasma glucose level was 84 mg/dL. The diagnosis of euDKA was made, and treatment with intravenous fluids and insulin was initiated. His chest pain and nausea subsequently resolved. CONCLUSION/CONCLUSIONS:We present a case of euDKA triggered by a ketogenic diet while on SGLT2 inhibitor therapy presenting as chest pain. The recognition of euDKA is important in the context of increased SGLT2 use for management of cardiovascular risk for patients with diabetes.

Many healthcare providers screen high-risk individuals exclusively with an HbA1c despite its insensitivity for detecting dysglycemia. The two cases presented describe the inherent caveats of interpreting HbA1c without performing an oral glucose tolerance test (OGTT). The first case reflects the risk of over-diagnosing type 2 diabetes (T2D) in an older African American male in whom HbA1c levels, although variable, were primarily in the mid- prediabetes range (5.7-6.4% [39-46 mmol/mol]) for many years although the initial OGTT demonstrated borderline impaired fasting glucose (IFG) with a fasting plasma glucose (FPG) of 102 mg/dl [5.7 mmol/L]) without evidence for impaired glucose tolerance (IGT) (2-hour glucose >140-199 mg/dl ([7.8 -11.1 mmol/L]). As subsequent HbA1c levels were diagnostic of T2D (6.5-6.6% [48-49 mmol/mol]), a second OGTT performed was normal. The second case illustrates the risk of under-diagnosing T2D in a male with HIV having normal HbA1c levels over many years who underwent an OGTT when mild prediabetes [HbA1c = 5.7% (39 mmol/mol)] developed which was diagnostic of T2D. To avoid inadvertent mistreatment, it is therefore essential to perform an OGTT, despite its limitations, in high-risk individuals particularly when glucose or fructosamine and HbA1c values are discordant. Innate differences in the relationship between fructosamine or fasting glucose to HbA1c are demonstrated by the glycation gap or hemoglobin glycation index.

Quality Improvement Success Stories are published by the American Diabetes Association in collaboration with the American College of Physicians, Inc., and the National Diabetes Education Program. This series is intended to highlight best practices and strategies from programs and clinics that have successfully improved the quality of care for people with diabetes or related conditions. Each article in the series is reviewed and follows a standard format developed by the editors of Clinical Diabetes. The following article describes the establishment of a Diabetes Prevention Clinic for veterans with prediabetes.

Prediabetes (intermediate hyperglycemia) consists of two abnormalities, impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) detected by a standardized 75-gram oral glucose tolerance test (OGTT). Individuals with isolated IGT or combined IFG and IGT have increased risk for developing type 2 diabetes (T2D) and cardiovascular disease (CVD). Diagnosing prediabetes early and accurately is critical in order to refer high-risk individuals for intensive lifestyle modification. However, there is currently no international consensus for diagnosing prediabetes with HbA1c or glucose measurements based upon American Diabetes Association (ADA) and the World Health Organization (WHO) criteria that identify different populations at risk for progressing to diabetes. Various caveats affecting the accuracy of interpreting the HbA1c including genetics complicate this further. This review describes established methods for detecting glucose disorders based upon glucose and HbA1c parameters as well as novel approaches including the 1-hour plasma glucose (1-h PG), glucose challenge test (GCT), shape of the glucose curve, genetics, continuous glucose monitoring (CGM), measures of insulin secretion and sensitivity, metabolomics, and ancillary tools such as fructosamine, glycated albumin (GA), 1,5- anhydroglucitol (1,5-AG). Of the approaches considered, the 1-h PG has considerable potential as a biomarker for detecting glucose disorders if confirmed by additional data including health economic analysis. Whether the 1-h OGTT is superior to genetics and omics in providing greater precision for individualized treatment requires further investigation. These methods will need to demonstrate substantially superiority to simpler tools for detecting glucose disorders to justify their cost and complexity.

For over 100 years, the oral glucose tolerance test (OGTT) has been the cornerstone for detecting prediabetes and type 2 diabetes (T2DM). In recent decades, controversies have arisen identifying internationally acceptable cut points using fasting plasma glucose (FPG), 2-h post-load glucose (2-h PG), and/or HbA1c for defining intermediate hyperglycemia (prediabetes). Despite this, there has been a steadfast global consensus of the 2-h PG for defining dysglycemic states during the OGTT. This article reviews the history of the OGTT and recent advances in its application, including the glucose challenge test and mathematical modeling for determining the shape of the glucose curve. Pitfalls of the FPG, 2-h PG during the OGTT, and HbA1c are considered as well. Finally, the associations between the 30-minute and 1-hour plasma glucose (1-h PG) levels derived from the OGTT and incidence of diabetes and its complications will be reviewed. The considerable evidence base supports modifying current screening and diagnostic recommendations with the use of the 1-h PG. Measurement of the 1-h PG level could increase the likelihood of identifying high-risk individuals when the pancreatic ß-cell function is substantially more intact with the added practical advantage of potentially replacing the conventional 2-h OGTT making it more acceptable in the clinical setting.