Annual Oral Glucose Tolerance Test Research Articles

Vitamin D 20,000 IU per Week for Five Years Does Not Prevent Progression From Prediabetes to Diabetes.

Vitamin D deficiency is associated with insulin resistance and risk of future diabetes. The objective of the study was to test whether supplementation with vitamin D to subjects with prediabetes will prevent progression to type 2 diabetes mellitus (T2DM). This was a randomized controlled trial performed in 2008 through 2015. The study was conducted at the clinical research unit at a teaching hospital. Five hundred eleven subjects (mean age 62 y, 314 males) with prediabetes diagnosed with an oral glucose tolerance test as part of the Tromsø Study 2007–2008 were included. A total of 256 were randomized to vitamin D and 255 to placebo. Twenty-nine subjects in the vitamin D and 24 in the placebo group withdrew because of adverse events. Interventions included vitamin D (cholecalciferol) 20 000 IU/wk vs placebo for 5 years. Annual oral glucose tolerance tests were performed. Progression to T2DM was the main outcome measure. Secondary outcomes were change in glucose levels, insulin resistance, serum lipids, and blood pressure. The mean baseline serum 25-hydroxyvitamin D level was 60 nmol/L (24 ng/mL). One hundred three in the vitamin D and 112 in the placebo group developed T2DM (hazard risk 0.90; 95% confidence interval 0.69–1.18, Cox regression, P = .45, intention to treat analysis). No consistent significant effects on the other outcomes were seen. Subgroup analyses in subjects with low baseline 25-hydroxyvitamin D yielded similar results. No serious side effects related to the intervention were recorded. In subjects without vitamin D deficiency, vitamin D supplementation is unlikely to prevent progression from prediabetes to diabetes. Very large studies with inclusion of vitamin D-deficient subjects will probably be needed to show such a putative effect. This study tested if supplementation with vitamin D to subjects with prediabetes will prevent progression to type 2 diabetes (T2DM).

Improving screening for diabetes in cystic fibrosis.

Annual screening for cystic fibrosis-related-diabetes (CFRD) using oral glucose tolerance test (OGTT) is recommended, but national testing rates are low. The purpose of this paper is to implement the quality improvement (QI) initiative to improve cystic fibrosis (CF) annual screening rates among patients at one CF center. To improve screening for CFRD at the CF Center, the authors used the Dartmouth Microsystem Improvement Ramp method and formed a collaborative working group. A process map was created to outline the steps and a fishbone analysis was performed to identify barriers and to utilize resources for implementing new interventions. Prior to these interventions, 21 percent of eligible patients had completed annual screening and after the intervention, it rose to 72 percent. The initial completion rate with the first prescription was only 50 percent, but it improved steadily to 54/75 (72 percent) in response to reminder letters sent six weeks after the initial script was given. Close tracking and reminder letters can improve adherence with annual OGTT screening for CFRD among CF patients, with special emphasis on high-risk patients. There should be a special emphasis on screening for CFRD in high-risk CF patients (those with low BMI or higher age). This QI initiative brought about several operational changes in the annual OGTT screening process that have now become the standard operating procedure at the center.

177 Evolution of glycemia, insulinemia and glycosylated hemoglobin in a CF pediatric population

Objectives Prevalence of Cystic Fibrosis Related Diabetes (CFRD) increases with age. Early screening is essential. The objective is to document evolution of glycemia, insulinemia and glycosylated hemoglobin levels (HbA1c) in CF pediatric patients (pts). Methods Chart review of 137 pts followed at CHU Sainte-Justine CF Clinic between 1993 and 2014. We collected results from annual oral glucose tolerance test and insulinemia of 119 pancreatic-insufficient (PI) and 18 pancreatic-sufficient pts (PS) aged 10 to 18. We also recorded HbA1c from age 1 to 18. Results Between 10 and 18 years, prevalence of normal glucose tolerance (NGT) decreased from 84 to 61% whereas impaired glucose tolerance and new CFRD increased from 13 to 32% and 3 to 7% respectively in PI. All PS remained NGT. Mean fasting glycemia increased from 5.3 to 5.9 mmol/L in PI but remained stable at 5.0 mmol/L in PS. Two-hour glycemia increased from 6.5 to 7.5 mmol/L in PI vs 5.3 to 6.2 mmol/L in PS. Fasting and 2-hour insulinemia increased from 31.2 to 34.6pmol/L and 162.6 to 268.5pmol/L in PI. PS displayed marked fluctuations of their insulinemia with values ranging from 33.0 to 72.1pmol/L (fasting) and 219 to 365pmol/L (2-hour). Between the age of 1 and 18 years, HbA1c increased gradually from 5.4 to 6.2% in PI vs 5.0 to 5.4% in PS. Conclusion We observed a decrease in glucose tolerance in PI with time characterized by an increase in fasting and 2-hour glycemia and insulinemia between the age of 10 and 18. Increase in 2-hour insulinemia and glycemia might suggest insulin resistance. Interestingly, HbA1c were higher in PI vs PS as early as 1 year old. Our findings emphasize the need for early monitoring of CFRD.

Improving Screening for Cystic Fibrosis–Related Diabetes at a Pediatric Cystic Fibrosis Program

Despite guidelines recommending an annual oral glucose tolerance test (OGTT) for all patients with cystic fibrosis (CF) aged ≥ 10 years, screening rates for cystic fibrosis-related diabetes (CFRD) remained low at our center. The aim of this project was to implement an outpatient system to provide effective, evidence-based screening for CFRD at a pediatric CF program. Development of a system to improve outpatient screening for CFRD included structured education, communication with families, and processes for scheduling laboratory appointments. The primary outcome measure was the proportion of eligible patients seen at the clinic who received an OGTT by the subsequent clinic appointment. The proportion of patients without CFRD in our program who received an OGTT within the previous 12 months was also tracked longitudinally. The outpatient screening rate for CFRD increased from 2% of eligible patients seen at the clinic during the 18 weeks before the start of our initiative to 78% during the 18 weeks after the start of our initiative (P < .001). The screening rate was also increased from the corresponding date range the previous year, when only 35% of eligible patients received an OGTT (P < .001). The overall percentage of patients without CFRD in our program who received an OGTT in the previous 12 months increased from 47% to 71% after implementation of our initiative (P = .003). A systematic, quality improvement approach effectively increased the rate of outpatient screening for CFRD at a pediatric CF program.

Predictors for future cystic fibrosis-related diabetes by oral glucose tolerance test

An annual oral glucose tolerance test (OGTT) has become part of standard care in cystic fibrosis (CF) to screen for CF-related diabetes (CFRD). The objective of this study was to determine predictors for future CFRD derived from an OGTT. Data were collected from 2001 to 2009 during a longitudinal prospective study on "Early Diagnosis of Diabetes Mellitus in CF Patients, trial number NCT00662714". The 1093 patients included in the analysis had at least two valid OGTTs each and no CFRD at the first glucose challenge. Normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and CFRD were defined using WHO criteria. In a subsample of 521 patients, the NGT group was further divided into patients with a 1-hour glucose level >11.1 mmol/l (indeterminate glucose tolerance -- INDET) and those with a lower level (no-INDET). Logistic regression analysis was used to identify predictors from the first OGTT for future diabetes. Compared with NGT (n = 838), IFG (n = 70; odds ratio [OR], 95% confidence interval: 2.92, 1.60-5.33) and IGT without IFG (n = 155, OR 2.37, 1.48-3.79) were both significant and independent risk factors for future CFRD. Patients with IGT and IFG (n = 30) had the highest risk (OR 5.30, 2.32-12.10). In the subsample analysis, INDET (n = 116) was associated with a significantly increased risk for future CFRD compared with no-INDET (n = 269; OR 2.81, 1.43-5.51). In this large study, IFT, IGT, and INDET were all predictors of future CFRD. The OGTT in patients with CF should include a 1-hour post-challenge value.

Diabetes-Free Survival in Patients Who Underwent Islet Autotransplantation After 50% to 60% Distal Partial Pancreatectomy for Benign Pancreatic Tumors

Several retrospective studies with short-term follow-up have demonstrated a low rate of new-onset diabetes after distal pancreatectomy for benign pancreatic tumors. We sought to determine the long-term diabetes-free survival of patients who underwent islet autotransplantation (IAT) after distal pancreatectomy and to identify any associations between the isolation parameters of autologous islets and diabetes-free survival. Among the 37 nondiabetic patients who underwent 50% to 60% partial pancreatectomy, 20 underwent IAT (IAT group; median follow-up period, 61 months). In the IAT group, diabetes-free survival was determined based on annual oral glucose tolerance tests, fasting blood glucose, and hemoglobin A1C. The 7-year diabetes-free survival rate was 51% in the IAT group (median follow-up period, 61 months) and 45% in the 37 study subjects. Diabetes-free survival was significantly prolonged when islet yield per gram of pancreas weight was more than 5154 islet equivalents (IEQ)/g, even in patients with prediabetes and high insulin resistance who had a markedly high rate of diabetes development. The proportion of patients with impaired glucose tolerance at 2 years after distal pancreatectomy was 12 of 16 in the control group, 6 of 7 in patients with islet yields of less than 5154 IEQ/g, and 3 of 11 in patients with islet yields of more than 5154 IEQ/g (P=0.019). Partial (50%-60%) pancreatectomy for benign pancreatic tumors had a major metabolic consequence, especially in patients with prediabetes and high insulin resistance. In this setting, prolonged diabetes-free survival was observed in patients who underwent IAT when a high islet yield per gram of pancreas was achieved.

Unreliable oral glucose tolerance test and haemoglobin A1C in beta thalassaemia major – a case for continuous glucose monitoring?

Unreliable oral glucose tolerance test and haemoglobin A1C in beta thalassaemia major – a case for continuous glucose monitoring?

Glucose Derangements in Very Young Children With Cystic Fibrosis and Pancreatic Insufficiency

Cystic fibrosis–related diabetes (CFRD) is considered the most common comorbidity in patients affected by cystic fibrosis (CF), with a prevalence increasing with age (1). Recently, more attention has been turned to other less severe glucose metabolism derangements (GMD), since prediabetes may be related to increased morbidity (1), and early treatment may improve the clinical course in patients with CF (2). According to recent guidelines released by the Cystic Fibrosis Foundation, the American Diabetes Association, and the Pediatric Endocrine Society, the oral glucose tolerance test (OGTT) is recommended yearly in patients with CF over 10 years of age (3). Some authors recommend annual OGTT after the age of 6 years in CF patients with pancreatic insufficiency (4). In …

Portal Venous Versus Systemic Venous Drainage of Pancreas Grafts: Impact on Long-Term Results

Portal venous (PV) and systemic venous (SV) drainage methods are used in pancreas transplantation. The impact of the reconstruction technique on long-term outcome remains unclear. We compared the efficacy and side effects of both methods in 192 recipients who received synchronous pancreas kidney transplants between November 1995 and November 2007. SV and PV drainage were used in 147 and 45 cases, respectively. Pancreas function was determined by hemoglobin A1c levels and annual oral glucose tolerance test. Serum creatinine assessed kidney function. Serum lipid (low-density lipoprotein, high-density lipoprotein and cholesterol) levels and body mass index were measured annually. Patient and graft survival were calculated by log-rank analysis. Pancreas survival for SV versus PV patients was similar after 5 years (81.8% vs. 75.5%) and 10 years (65.1% vs. 60%; p = NS). Similarly, no difference was detected between the groups regarding kidney survival after 5 years (92.9% vs. 84.4%) and 10 years (81.6% vs. 75.5%; p = NS). Patient survival did not differ at 5 years (94.3% vs. 88.8%) and 10 years (85.1% vs. 84.4%; p = NS). Pancreas and kidney function and the lipid profiles were similar in both groups. SV and PV drainage of pancreas grafts offer similar long-term graft survival and function and choice of method should remain the preference of the surgeon.

Prognostic Relevance of Hypoglycemia Following an Oral Glucose Challenge for Cystic Fibrosis–Related Diabetes

An annual oral glucose tolerance test (OGTT) has become part of standard care in cystic fibrosis (CF) to screen for CF-related diabetes (CFRD) in patients older than 10 years of age (1). Up to 15% of patients with CF develop hypoglycemia during an OGTT (2), and there is some discussion whether such a response indicates an increased risk for the development of CFRD. In fact, a reactive hypoglycemia has been considered as an early stage of CFRD (3). However, the prognostic value of such a reactive hypoglycemia with respect to future glucose control has never been studied. Based on a delayed insulin secretion in CF, which might be relevant to both a hypoglycemic as well as a hyperglycemic response to a glucose challenge (4), we hypothesized that the hypoglycemic response to a glucose …

Management of cystic fibrosis-related diabetes in children and adolescents

TheDepartment of Pediatrics, University of Minnesota Children’sHospital, Minneapolis, USACorresponding author:Dr. Stephen MP O’Riordan MRCPI, MDThe Developmental Endocrinology and Research GroupThe Department of Clinical and Molecular GeneticsThe Institute of Child Health, University College London30 Guliford StreetLondon WC1N 1EH.Tel: +44-020-7242-9789, ext. 0732;fax: +44-020-7404-6191;e-mail: s.oriordan@ich.ucl.ac.ukAcknowledgments:PeterHindmarsh,MehulDattani,HilaryHoeyand Nicola Bridges.Conflicts of interest: The authors have declared no conflictsof interest.Editors of the ISPAD Clinical Practice Consensus Guide-lines 2009 Compendium: Ragnar Hanas, Kim Donaghue,Georgeanna Klingensmith, and Peter Swift.This article is a chapter in the

Value of waist circumference, body mass index and hyperinsulinaemia in identifying metabolic syndrome

To investigate the significance of waist circumference (WC), body mass index (BMI) and hyperinsulinaemia A (HIns) in evaluating metabolic syndrome (MS). Clinical data from middle-aged and senile individuals (middle-senile group) who received glucose tolerance test after diabetes mellitus screening and a group of subjects who received annual oral glucose tolerance test (OGTT) for diabetes mellitus screening (adult group) were collected. Data were collected by use of special messengers, input into a computer data base and analyzed using SAS 5.0 software by expert staff. Abnormal WC and BMI were determined according to International Diabetes Federation (IDF) and Chinese Diabetes Society (CDS) criteria. HIns was ascertained if fasting insulin (FIns) ⩾ 15 mU/L, and/or 2-hour insulin after a glucose challenge was (2hPIns) ⩾ 80 mU/L. Abnormalities in WC, BMI and HIns were all found to be risk factors for abnormal glucose metabolism, hypertension and dyslipidemia. In the middle-senile group, the abnormality rate of WC and HIns as well as the overall insulin level were significantly higher than those in the adult group. The abnormality rate of BMI was higher in the adult group, and HIns was mostly seen in impaired glucose test (IGT) and normal glucose test (NGT). The concordance rate of WC and BMI diagnostic criteria for evaluating obesity in the middle-senile and adult groups were 77.5% and 74.3%, respectively. When only the WC criterion was used for evaluating the existence of insulin resistance, there was a 28.2%missed diagnosis rate for MS patients. WC, BMI and HIns were all risk factors for abnormal glucose metabolism, hypertension and dyslipidemia. There was differing prevalence in the different populations. The combination of WC, BMI and HIns might be more helpful in identifying MS at early stage.

Psychosocial factors are independent risk factors for the development of Type 2 diabetes in Japanese workers with impaired fasting glucose and/or impaired glucose tolerance1

AimsWe prospectively studied Japanese workers with impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) and analysed possible risk factors for diabetes, including psychosocial factors such as stress.MethodsThe participants were 128 male Japanese company employees (mean age, 49.3 ± 5.9 years) with IFG and/or IGT diagnosed by oral glucose tolerance test (OGTT). Participants were prospectively studied for 5 years with annual OGTTs. The Kaplan–Meier method and Cox's proportional hazard model were used to analyse the incidence of diabetes and the factors affecting glucose tolerance, including anthropometric, biochemical and social–psychological factors.ResultsOf 128 participants, 36 (28.1%) developed diabetes and 39 (30.5%) returned to normal glucose tolerance (NGT) during a mean follow-up of 3.2 years. Independent risk factors for diabetes were night duty [hazard ratio (HR) = 5.48, P = 0.002], higher fasting plasma glucose (FPG) levels within 6.1–6.9 mmol/l (HR = 1.05, P = 0.031), stress (HR = 3.81, P = 0.037) and administrative position (HR = 12.70, P = 0.045), while independent factors associated with recovery were lower FPG levels (HR = 0.94, P = 0.017), being a white-collar worker (HR = 0.34, P = 0.033), non-smoking (HR = 0.31, P = 0.040) and lower serum alanine aminotransferase (ALT) levels (HR = 0.97, P = 0.042).ConclusionsIn addition to FPG levels at baseline, psychosocial factors (night duty, stress and administrative position) are risk factors for Type 2 diabetes, while being a white-collar worker, a non-smoker and lower serum ALT levels are factors associated with return to NGT in Japanese workers with IFG and/or IGT.

Is it necessary for all adult cystic fibrosis patients to have an annual oral glucose tolerance test (OGTT)?

Is it necessary for all adult cystic fibrosis patients to have an annual oral glucose tolerance test (OGTT)?

Treatment of the first tonic-clonic seizure does not affect long-term remission of epilepsy

We followed 419 patients with a first, unprovoked, primarily or secondarily generalized tonic-clonic seizure, randomized to immediate antiepileptic treatment or to treatment only in the event of seizure recurrence. The probability of achieving a 2-year remission was 72 vs 57% at 3 months, 84 to 79% at 3 years, and 85 to 86% at 10 years (p = NS). The probability of entering 5-year remission was 47 to 40, 58 to 58, and 64 to 64% (p = NS). Early treatment does not affect the long-term prognosis of epilepsy.

Treating Postprandial Hyperglycemia Does Not Appear to Delay Progression of Early Type 2 Diabetes

Postprandial hyperglycemia characterizes early type 2 diabetes. We investigated whether ameliorating postprandial hyperglycemia with acarbose would prevent or delay progression of diabetes, defined as progression to frank fasting hyperglycemia, in subjects with early diabetes (fasting plasma glucose [FPG] <140 mg/dl and 2-h plasma glucose > or =200 mg/dl). Two hundred nineteen subjects with early diabetes were randomly assigned to 100 mg acarbose t.i.d. or identical placebo and followed for 5 years or until they reached the primary outcome (two consecutive quarterly FPG measurements of > or =140 mg/dl). Secondary outcomes included measures of glycemia (meal tolerance tests, HbA(1c), annual oral glucose tolerance tests [OGTTs]), measures of insulin resistance (homeostasis model assessment [HOMA] of insulin resistance and insulin sensitivity index from hyperglycemic clamps), and secondary measures of beta-cell function (HOMA-beta, early- and late-phase insulin secretion, and proinsulin-to-insulin ratio). Acarbose significantly reduced postprandial hyperglycemia. However, there was no difference in the cumulative rate of frank fasting hyperglycemia (29% with acarbose and 34% with placebo; P = 0.65 for survival analysis). There were no significant differences between groups in OGTT values, measures of insulin resistance, or secondary measures of beta-cell function. In a post hoc analysis of subjects with initial FPG <126 mg/dl, acarbose reduced the rate of development of FPG > or =126 mg/dl (27 vs. 50%; P = 0.04). Ameliorating postprandial hyperglycemia did not appear to delay progression of early type 2 diabetes. Factors other than postprandial hyperglycemia may be greater determinants of progression of diabetes. Alternatively, once FPG exceeds 126 mg/dl, beta-cell failure may no longer be remediable.

New criteria for impaired fasting glucose and screening for diabetes in cystic fibrosis: Fig. 1—

Cystic fibrosis-related diabetes mellitus (CFRD) is the most frequent comorbidity in cystic fibrosis. Its clinical relevance is stressed by the association with increased mortality, and decreased pulmonary and nutritional status. An annual oral glucose tolerance test (OGTT) is recommended as a screening test for CFRD, but this is often not realised because of its time- and resource-consuming nature. Therefore, alternative approaches are welcome. In 2003, the American Diabetes Association (ADA) lowered the cut-off point separating normal from elevated fasting plasma glucose from <6.1 mmol x L(-1) to <5.6 mmol x L(-1), suggesting the performance of an OGTT only in those with impaired fasting glucose (IFG; range 5.6-6.0 mmol x L(-1)). The current authors tested whether this approach was reliable for the early identification of patients with CFRD. OGTTs from 1,128 patients (53% males; 47% females; median age 17.1 yrs) were available for analysis. A total of 101 (8.9%) OGTTs were classified as diabetic. The new ADA criteria for IFG increased the sensitivity to 82% (versus 65%) and decreased the specificity to 70% (versus 94%) compared with the old criteria used to identify patients with diabetic OGTTs. In conclusion, the American Diabetes Association approach of using impaired fasting glucose as an indication for performing selective oral glucose tolerance tests is definitely unsuitable when aiming at the early identification of patients with cystic fibrosis-related diabetes mellitus, and it cannot replace annual oral glucose tolerance tests.

Cystic fibrosis-related diabetes.

Diabetes mellitus (DM) has been recognized as a complication of cystic fibrosis (CF) for almost 50 years and commonly develops around 20 years of age. The prevalence increases with age and, with improved survival of those with CF, approaches 30% in certain centres. Its development appears to have a significant impact on pulmonary function and may increase mortality by up to six-fold. Subjects with CF are rarely ketosis-prone and phenotypically lie between Type 1 and Type 2 DM. Microvascular complications are recognized, although paucity of data does not permit a clear description of their natural history. An annual oral glucose tolerance test from the age of 10 years is recommended for screening, but logistical difficulties have led some groups to develop specific algorithms to aid diagnosis. Insulin sensitivity in CF is much debated and may depend upon the degree of glucose intolerance. Insulin resistance occurs in the presence of infection, corticosteroid usage and hyperglycaemia, whilst hepatic insulin resistance is considered an adaptation to CF. There is no universal consensus on the treatment of hyperglycaemia. With increased longevity of individuals with CF, greater numbers will develop diabetes and the diabetes physician is destined to play a greater role in the multidisciplinary CF team.

Glucose tolerance in patients with cystic fibrosis: five year prospective study.

To study prevalence and incidence of diabetes mellitus in patients with cystic fibrosis. Five year prospective study with annual oral glucose tolerance tests. CF Center Copenhagen, Denmark. 191 patients with cystic fibrosis aged above 2 years. Glucose tolerance, plasma glucose concentrations after fasting and after glucose loading, and haemoglobin A1c levels. Prevalence of diabetes increased from 11% (n = 21) to 24% (n = 46) during study, with annual age dependent incidence of 4-9%. Diabetes was diagnosed at median age of 21 (range 3-40). At diagnosis of diabetes, symptoms of hyperglycaemia were present in 33% of patients, fasting hyperglycaemia (> or = 7.8 mmol/l) was seen in 16%, and increased haemoglobin A1c levels (> 6.4%) were seen in 16%. Impaired glucose tolerance implied higher risk for development of diabetes than normal glucose tolerance (odds ratio 5.6). In 58% of cases with impaired glucose tolerance, however, glucose tolerance was normal at next annual test. Normal glucose tolerance was found in only 37% of patients at all five tests. Within this group of patients, median plasma glucose concentrations after fasting and after glucose loading and haemoglobin A1c levels increased by 6-8% during study. Prevalence and incidence of diabetes in cystic fibrosis patients was high and increased with age. Since hyperglycaemic symptoms, fasting hyperglycaemia, and increased levels of glycated haemoglobin did not reliably identify diabetes mellitus, we recommend annual oral glucose tolerance tests in all cystic fibrosis patients aged over 10 years.

The limp child.

Cystic fibrosis-related diabetes mellitus (CFRD) is the most frequent comorbidity in cystic fibrosis. Its clinical relevance is stressed by the association with increased mortality, and decreased pulmonary and nutritional status. An annual oral glucose tolerance test (OGTT) is recommended as a screening test for CFRD, but this is often not realised because of its time- and resource-consuming nature. Therefore, alternative approaches are welcome. In 2003, the American Diabetes Association (ADA) lowered the cut-off point separating normal from elevated fasting plasma glucose from &lt;6.1 mmol·L⁻¹ to &lt;5.6 mmol·L⁻¹, suggesting the performance of an OGTT only in those with impaired fasting glucose (IFG; range 5.6–6.0 mmol·L⁻¹). The current authors tested whether this approach was reliable for the early identification of patients with CFRD. OGTTs from 1,128 patients (53% males; 47% females; median age 17.1 yrs) were available for analysis. A total of 101 (8.9%) OGTTs were classified as diabetic. The new ADA criteria for IFG increased the sensitivity to 82% (<i>versus</i> 65%) and decreased the specificity to 70% (<i>versus</i> 94%) compared with the old criteria used to identify patients with diabetic OGTTs. In conclusion, the American Diabetes Association approach of using impaired fasting glucose as an indication for performing selective oral glucose tolerance tests is definitely unsuitable when aiming at the early identification of patients with cystic fibrosis-related diabetes mellitus, and it cannot replace annual oral glucose tolerance tests.