Utility of HbA1c in the detection of subclinical post renal transplant diabetes

BACKGROUND: We hypothesized that the use of HbA1c testing would help identify postrenal transplant diabetes (PTDM). METHODS: In all, 199 adult kidney transplant recipients at least 3 months posttransplant without previous history of diabetes or elevated fasting blood sugar were studied. Medical history, a fasting blood glucose, calcineurin inhibitor blood level, and HbA1c were obtained. Primary outcome was the incidence of subjects with HbA1c > or =6.1%. The covariates were use of cyclosporine or tacrolimus, time posttransplant, body mass index (BMI) at transplant and change since transplant, current steroid dose, history of graft rejection, current fasting glucose, age, and race. Proportions were compared between HbA1c <6 and > or =6.1% using Fisher's exact test. Means were compared using Student's t test. Logistic regression was used to identify risk factors associated with elevated HbA1c. RESULTS: Twenty subjects (10.1%) had an elevated HbA1c. High normal fasting glucose (P=0.003) and African American race (P=0.08, marginally significant) were found to be associated with an elevated HbA1c. Subjects with normal and abnormal HbA1c levels were otherwise similar. There was no difference in HbA1c in tacrolimus versus cyclosporine treated subjects or in the percent of subjects with elevated HbA1c between these groups. CONCLUSIONS: HbA1c levels were found to be more a more sensitive test than fasting blood glucose levels in PTDM, with 10.1% of all patients and 19.4% of blacks found to have an elevated HbA1c. HbA1c testing should be considered as a screening test for PTDM, especially in African Americans.     

Preoperative hemoglobin A1c and postoperative glucose control in outcomes after gastric bypass for obesity

BACKGROUND: Hemoglobin A1c (HbA1c) is a reliable marker for long-term glycemic control in obese diabetic patients. Roux-en-Y gastric bypass improves HbA1c levels over time. However, it is not clear whether the preoperative HbA1c level is a predictor of the outcome in these patients. Our objectives were to understand the predictive capacity of the preoperative HbA1c level in gastric bypass patients at a single university-based Bariatric Center of Excellence. METHODS: We performed a retrospective review of 468 charts from 2006 to 2009 of patients who had undergone Roux-en-Y gastric bypass. Using their preoperative HbA1c status, the patients were categorized and the postoperative outcomes compared. RESULTS: Of the 468 patients reviewed, 310 (66.2%) had a HbA1c of <6.5% (group 1), 92 (19.4%) had a HbA1c of 6.5-7.9% (group 2), and 66 (14.1%) had a HbA1c level of >8.0% (group 3). No difference was found among the 3 groups in baseline body mass index, race, procedure type, length of stay, hospital cost, and smoking status. Groups 2 and 3 were associated with older age, male gender, and higher baseline creatinine. Groups 2 and 3 also had a proportionally greater inpatient postoperative blood glucose level. An elevated postoperative glucose level was independently associated with wound infection (P = .008) and acute renal failure (P = .04). Also, group 3 experienced worse outcomes, including less weight loss at 18 months and fewer diabetic remissions. Over time, however, the vast majority in all groups achieved excellent chronic glycemic control, with HbA1c <6.5% after Roux-en-Y gastric bypass. CONCLUSION: Poor preoperative glycemic control is associated with worse glucose level control postoperatively, fewer diabetic remissions, and less weight loss. An elevated mean postoperative glucose level is independently associated with increased morbidity.     

妊娠期糖尿病(A2级)的高危因素分析及早期诊断

目的探讨妊娠期糖尿病(GDM)妊娠早期血糖监测的时机和方法,以期提高GDM患者孕期保健指导的针对性,减少GDM的母婴危害。方法随机选择孕期需胰岛素控制血糖的GDM患者(GDMA2)100例为观察组,同期体检的仅需饮食控制血糖的GDM患者(GDMA1)100例为对照组。分析两组患者常见风险因素的差异,比较两组患者孕早期空腹血糖水平、孕24周口服葡萄糖耐量实验(OGTT)及糖化血红蛋白(HbA1c)结果的差异。结果纳入的GDM病例中孕前体重指数(BMI)25kg/m2者过半(GDMA1,58%;GDMA2,53%);GDMA2组患者有糖尿病家族史及不良孕产史的比例较高(P0.05),孕24周HbA1c水平及OGTT结果亦显著高于GDMA1组(P0.05);GDMA2孕妇24周HbA1c6.0%者的比例为81%,显著高于GDMA1孕妇的比例(28%)(P0.05)。结论对于有糖尿病家族史及既往不良孕产史的肥胖孕妇应加强早期血糖监测。在孕24周之前检测HbA1c可能有助于早期发现GDM。     

Hemoglobin A1c in early postpartum screening of women with gestational diabetes

AIM: To assess the utility of hemoglobin A1c (HbA1c) in the early postpartum screening of women with gestational diabetes mellitus (GDM).METHODS: Over a 3 years period, HbA1c estimations were undertaken in addition to and simultaneously with the traditional oral glucose tolerance test (OGTT), in 203 women with GDM as a part of early postpartum screening for dysglycaemia, at 6 wk post-partum. World Health Organization criteria was used for diagnosing diabetes: fasting blood glucose (FBG) ≥ 7.0 mmol/L and/or 2-h postprandial blood glucose (PPBG) ≥ 11.1 mmol/L and/or HbA1c ≥ 48 mmol/mol; and impaired glycaemiastate: impaired fasting glucose 6.1-6.9 mmol/L and/or impaired glucose tolerance 7.8-11.0 mmol/L and/or HbA1c: 42-47 mmol/mol.RESULTS: Mean FBG, 2-h PPBG and HbA1c were 4.9 ± 0.7 mmol/L, 5.6 ± 2.0 mmol/L and 38 ± 5 mmol/mol respectively. FBG, 2-h PPBG and HbA1c detected 6 (3%), 7 (3.5%) and 11 (5.4%) cases of diabetes respectively, and 11 (5.4%), 25 (12.3%) and 23 (11.3%) cases of pre-diabetes state respectively. HbA1c values ≥ 48 mmol/mol (≥ 6.5%) showed a diagnostic sensitivity of 71.4% and specificity of 98.5% for diabetes in comparison to OGTT in receiver operating characteristics curve analysis. At HbA1c cut-off 44 mmol/mol, sensitivity and specificity were 100% and 92.3% respectively [area under the curve: 0.98 (95%CI: 0.96-1.00)]. Sensitivity and specificity for detecting high risk “impaired glycaemia” state [HbA1c 42 mmol/mol (6.0%)] were 28% and 80%, respectively.CONCLUSION: HbA1c level ≥ 48 mmol/mol (≥ 6.5%) has reasonable sensitivity and high specificity in comparison to OGTT for early postpartum screening of diabetes in GDM. At 6^th week postpartum screening, if FBG is normal and HbA1c < 44 mmol/mol OGTT is not recommended.     

Relationship between glycosylated haemoglobin and mean plasma glucose concentration in cystic fibrosis.

BACKGROUND: HbA(1c) is recommended for monitoring glycaemic control in people with cystic fibrosis-related diabetes (CFRD). However the relationship between HbA(1c) and mean plasma glucose concentration (MPG) has not been established in CFRD, as in other forms of diabetes mellitus. METHODS: 20 people (13 male, 29.7+/-8.8 years, 10 CFRD) with cystic fibrosis (CF) underwent HbA(1c) measurement and 48 h continuous glucose monitoring for estimation of MPG. The relationship between HbA(1c) and MPG was established and compared to the reported relationship for type 1 diabetes. RESULTS: HbA(1c) was strongly correlated with MPG (R(2)=0.888, p<0.0001) in CF. The relationship of MPG to HbA(1c) was described by the equation MPG=(1.47xHbA(1c))-1.15, giving a 1.47 mmol L(-1) change in MPG per 1% change in HbA(1c). This equation predicts that MPG in people with CF and HbA(1c) <7.0% will be similar to MPG in people with type 1 diabetes who achieve the same HbA(1c) target. CONCLUSIONS: These results imply that HbA(1c)<7.0% will predict good blood glucose control in CF as in type 1 diabetes. However, although HbA(1c) predicts complications in type 1 diabetes, further studies are required to establish the relationship between HbA(1c) and diabetic complications in people with CFRD.     

HbA(1c) levels are genetically determined even in type 1 diabetes: evidence from healthy and diabetic twins.

HbA(1c), a measure of blood glucose regulation, reflects glucose levels in the preceding months. In diabetes, HbA(1c) levels predict the risk of microvascular complications. The aim of this study was to determine whether genetic factors could influence HbA(1c) levels in normal subjects and type 1 diabetic patients. We performed a classical twin study of HbA(1c) in healthy nondiabetic female twins and 42 monozygotic (MZ) and 47 dizygotic (DZ) pairs. Interclass correlations (r) were higher in MZ (r = 0.77) compared with DZ (r = 0.53) twin pairs, suggesting a substantial genetic effect; this was confirmed by quantitative genetic model fitting. Additive genetic effects (heritability) explained 62% (95% CI 47-75) of population variance in HbA(1c); the remainder was attributable to the influence of unique environment (23% [15-36]) and age (14% [5-28]). Multivariate modeling showed that genetic factors also have a substantial influence on fasting glucose levels (51%). However, HbA(1c) heritability could not be explained by genes in common with fasting glucose. In the patients with type 1 diabetes, HbA(1c) levels were correlated in 33 MZ twins concordant for diabetes (r = 0.68; P < 0.001) but also in 45 MZ twins discordant for the disease (r = 0.52; P < 0.001). These significant correlations for HbA(1c) in both concordant and discordant pairs indicate a diabetes-independent familial effect. Thus, HbA(1c) levels are largely genetically determined and independent of the genes influencing fasting glucose. Even in type 1 diabetes, familial (i.e., diabetes-independent) factors influence protein glycation, implying that familial factors may explain, in part, the risk for microvascular complications, as indicated by high HbA(1c) levels.     

Successful management of a type 2 diabetic donor in living-donor liver transplantation: a case report

A 50-year-old woman with a 4-year history of type 2 diabetes history was treated with nateglinide (270 mg/day) and metformin hydrochloride (500 mg/day). The recipient was her 55-year-old husband whose diagnoses were liver cirrhosis with type C chronic hepatitis (Child-Pugh C, score, 10; Model for End-Stage Liver Disease: 15), hepatocellular carcinoma (solitary, 2 cm), and hepatic encephalopathy. Her body weight was 50 kg and body mass index 21.6 kg/m2. Laboratory examinations showed fasting blood glucose of 110 mg/dL and hemoglobin A1c (HbA1c) of 6.6% upon admission. Right liver lobectomy was performed of a 563-g graft. Operative time was 253 minutes and blood loss 50 mL. She was discharged at postoperative day 9 without any complications. We changed nateglinide and metformin hydrochloride to insulin aspart or human insulin after admission. Blood glucose level was strictly controlled using a sliding scale of insulin. She received regular glucose check-ups at our outpatient clinic after discharge. She stopped using insulin and returned to nateglinide and metformin hydrochloride on postoperative day 25. Her blood glucose level was 80 to 150 mg/dL and HbA1c was 5.8% at 5 months after surgery. This type 2 diabetic living liver donor showed good control of the postoperative glucose level without exacerbation or diabetic complications.     

Time-in-range: a promising glycemic control metric for bariatric surgery

As a complication of obesity, type 2 diabetes (T2D) is a chronic disease that is difficult to manage. However, bariatric surgery makes it possible to alleviate T2D. While the existing generic index glycosylated hemoglobin (HbA1c) is a powerful tool for examining overall blood glucose levels, it still has some limitations as a daily measure of blood glucose levels and as a judge of the effectiveness of bariatric surgery. Using the time-in-range (TIR) measurement and its derivatives is a better way to evaluate short-term blood glucose fluctuations and can be used as a supplement to HbA1c. In this article, we discuss the utility and limitations of HbA1c and other indicators used during surgery. In addition, we mentioned TIR as a novel metric that can act as an accurate predictor of the risk of T2D complications and an index of preoperative risk assessment in bariatric surgery. In contrast to previous indicators, TIR has the advantage that it cannot be affected by caloric restriction to better reflect the patient's glucose level and the level of pancreatic islet function. On this basis, TIR is a promising indicator for both the diagnosis of diabetes and the preoperative and postoperative prediction and evaluation.     

The use of glycosylated haemoglobin measurements in the control of the diabetic patient.

Glycosylated haemoglobin (HbA1c) has recently been used as an indicator of long-term diabetic control. This study compares the efficacy of HbA1c measurements and postprandial blood glucose estimations in assessing diabetic control in 51 diabetic patients. It was found that the HbA1c levels reflected overall diabetic control significantly better than did a single postprandial blood glucose estimation. HbA1c measurements give considerable aid in the assessment of the longitudinal blood sugar control in the diabetic, and may be a useful indicator of the efficacy of diabetic treatment.     

Association of HbA1c with prevalent cardiovascular disease in the original cohort of the Framingham Heart Study.

We studied the cross-sectional relationship between HbA1c and cardiovascular disease (CVD) in the survivors of the original cohort of the Framingham Heart Study (n = 1045). HbA1c was significantly related to prevalent CVD among women but not men. HbA1c was also related to hypertension and to the ratio of total to high-density lipoprotein cholesterol levels. In regression analyses that controlled for these and other potential risk factors, HbA1c remained significantly related to CVD among women. The relative odds of CVD increased 1.39-fold (95% confidence interval 1.06-1.83) for increases in HbA1c of 1% (e.g., for HbA1c from 5 to 6%). The relationship was not weakened when known diabetic subjects or subjects taking beta-blocker or thiazide medications were excluded from analysis. In contrast, there was no significant relationship between "casual" blood glucose and prevalent CVD. Our results reveal a strong, significant, independent association between hyperglycemia, measured by HbA1c, and CVD among older women.     

Use of glycated albumin for the identification of diabetes in subjects from northeast China

BACKGROUNDMetabolic memory is important for the diagnosis and treatment of diabetes in the early stage, and in maintaining blood glucose concentrations within the normal range. The clinical diagnosis of diabetes mellitus is currently made using fasting plasma glucose, 2 h-plasma glucose (2h-PG) during a 75 g oral glucose tolerance test, and hemoglobin A1c (HbA1c) level. However, the fasting plasma glucose test requires fasting, which is a barrier to screening, and reproducibility of the 2h-PG level is poor. HbA1c is affected by a shortened red blood cell lifespan. In patients with anemia and hemoglobinopathies, the measured HbA1c levels may be inaccurate. Compared with HbA1c, glycated albumin (GA) is characterized by more rapid and greater changes, and can be used to diagnose new-onset diabetes especially if urgent early treatment is required, for example in gestational diabetes. In this study, we provided cutoff values for GA and evaluated its utility as a screening and diagnostic tool for diabetes in a large high-risk group study.AIMTo evaluate the utility of GA in identifying subjects with diabetes in northeast China, and to assess the diagnostic accuracy of the proposed GA cutoff in the diagnosis of diabetes mellitus.METHODSThis cross-sectional study included 1935 subjects, with suspected diabetes or in high-risk groups, from 2014 to 2015 in the Second Affiliated Hospital of Harbin Medical University (Harbin, China). The use of GA to identify diabetes was investigated using the area under the receiver operating characteristic curve (AUC). The GA cutoffs were derived from different 2h-PG values with hemoglobin A1c cutoffs used as a calibration curve.RESULTSThe GA cutoff for the diagnosis of diabetes mellitus was 15.15% from the receiver operating characteristic (ROC) curve. ROC analysis demonstrated that GA was an efficient marker for detecting diabetes, with an AUC of 90.3%.CONCLUSIONOur study supports the use of GA as a biomarker for the diagnosis of diabetes.     

The influence of intravenous 1,25(OH)2D3 therapy on glucose metabolism in hemodialyzed patients with secondary hyperparathyroidism

Glucose intolerance, insulin resistance and hyperinsulinemia are common findings in end-stage renal disease patients. Parathormone (PTH) and vitamin D3 are linked with disturbances of glucose metabolism. Glycated hemoglobin (HbA1c) reflects long-term glycemic control. HbA1c is a marker of increased risk of death in diabetic patients but also in general population. The aim of the study was to investigate the influence of 1,25(OH)2D3 therapy on long-term control of glycemia in hemodialyzed (HD) patients with severe secondary hyperparathyroidism (SHP). Eight HD patients with SHP (PTH=1088.6+/-472.2) were given intravenous 1,25(OH)2D3 1-2 microg thrice a week, for 12 weeks (mean dose 4.5 microg/week). At baseline and after 12 weeks fasting blood was sampled for: glucose, insulin, HbA1c, PTH. Insulin/glucose ratio (I/G) was calculated as marker of insulin resistance. Results were compared with 14 healthy volunteers (controls) matched for age, sex and BMI. At baseline I/G was higher in HD vs controls 0.110+/-0.045 vs 0.073+/-0.021 (p = 0.02), and of borderline significance at follow-up (0.106+/-0.053, p=0.05 vs controls). PTH decreased significantly to 506.1+/-646.3 (p<0.02) during therapy. Significant decrease of HbA1c in HD patients was observed (5.84+/-0.40 vs 5.13+/-0.51; p=0.01), while fasting glucose, insulin and I/G did not change significantly. Intravenous 1,25(OH)2D3 therapy is successful, even in patients with severe secondary hyperparathyroidism. Significant decrease in HbA1c with stable insulin concentration may indicate positive impact of intravenous 1,25(OH)2D3 therapy on long-term glucose metabolism.     

A high-performance liquid chromatography method for hemoglobin A1c

Hemoglobin A1c (HbA1c) is a glycosylated derivative of hemoglobin and is one of a family of derivatives whose concentrations are elevated in patients with diabetes mellitus. Published methods for the measurement of HbA1c are relatively tedious and require modest amounts of blood. A high-performance liquid chromatographic (HPLC) method for the determination of HbA1c is presented. The method is rapid (20 minutes), precise (coefficient of variation of 5-10 per cent), uses small amounts of sample (3 microliter.), can be automated. A sample preparation technique using filtration was developed that shortened and simplified preparation of venous blood and allowed use of capillary samples. HbA1c was measured by this method in three age-stratified groups of controls and a group of insulin-requiring juvenile diabetics. There was clear separation of HbA1c values between all normals (5.9 +/- 1.3, 5.6 +/- 0.7, 7.1 +/- 0.9 per cent) and the diabetics (12.1 +/- 2.4 per cent). Use of this method can facilitate large-scale clinical investigations and permit biochemical investigations of the metabolism and formation of hemoglobin A1c where small sample sizes are necessary.     

Hemoglobin South Florida. New variant with normal electrophoretic pattern mistaken for glycosylated hemoglobin

An 8.75-yr-old Caucasian boy was discovered to have a markedly elevated (14.8%) hemoglobin A1c (HbA1c) as estimated by ion-exchange chromatography (Bio Rex 70). Glycohemoglobin (GHb) measured by a colorimetric method with thiobarbituric acid (TBA) was normal (equivalent to a 6.4% HbA1c). Nondiabetic quantities of GHb were found with affinity chromatography, and the glucose tolerance test was normal. Intensive efforts to identify an abnormal variant hemoglobin by several electrophoretic methods were unsuccessful. A family survey identified a similar abnormality in 11 other individuals, revealing an autosomal-dominant pattern. None of the affected individuals had any other hematologic abnormality. Structural analysis in one family member revealed a new hemoglobin variant (approximately 45% of the total hemoglobin) with the substitution of methionine for valine at the beta-NH2-terminal. In addition, the initiator methionine residue was preserved. Approximately 20% of the variant hemoglobin was modified by acetylation of the NH2-terminal methionine. The modified variant coeluted with HbA1c. We suggest that patients who do not have an explanation for their elevated HbA1c should have GHb measured by the TBA method or affinity chromatography because hemoglobin electrophoresis does not identify this confounding artifact.     

Blood glucose concentration profile after 10 mg dexamethasone in non-diabetic and type 2 diabetic patients undergoing abdominal surgery

Background. Dexamethasone prevents postoperative nausea andvomiting but may increase blood glucose. We compared blood glucoseconcentrations after dexamethasone in non-diabetic and type2 diabetic patients undergoing surgery and looked for any associationwith preoperative glycosylated haemoglobin [HbA (1c)] and BMI. Methods. Sixty three patients were enrolled: 32 were non-diabetic(Group ND) and 31 type 2 diabetic (Group D) without insulintreatment. Anaesthesia was induced using i.v. anaesthetic agentsand maintained with sevoflurane. All patients received 10 mgdexamethasone at induction. Blood glucose concentrations weremeasured at induction and then every 60 min for 240 min. Datawere analysed using ANOVA. Effects of HbA (1c) and BMI wereinvestigated using linear correlation and logistic regression. Results. Blood glucose concentrations increased significantlyover time and peaked at 120 min after 10 mg dexamethasone inboth groups. The magnitude of increase was comparable betweenthe groups [mean (SD) 29 (19) and 35 (19)% of baseline in GroupD and Group ND, respectively]. Maximum concentrations were higherin Group D [8.97 (1.51) mmol litre^–1, range 6.67–12.94mmol litre^–1] than in Group ND [7.86 (1.00) mmol litre^–1,range 5.78–10.00 mmol litre^–1]. There was a significantcorrelation between the maximum concentrations and BMI (R²=0.21)or HbA (1c) (R²=0.26). Logistic regression analysis revealedthat the higher the BMI, the lower the HbA (1c) threshold associatedwith an increased probability (>0.5) of observing blood glucoselevels higher than 8.33 mmol litre^–1 during 240 min afterdexamethasone administration. Similarly, the higher the HbA(1c), the lower the BMI threshold associated with the same probability. Conclusions. After 10 mg dexamethasone, blood glucose levelsincrease in non-diabetic and type 2 diabetic patients undergoingabdominal surgery. Poorly controlled diabetes and severe obesitycan influence the development of hyperglycaemia.     

Assessment of markers of glycaemic control in diabetic patients with chronic kidney disease using continuous glucose monitoring

Aim: Due to altered red blood cell survival and erythropoietin therapy glycated haemoglobin (HbA1c) may not accurately reflect long‐term glycaemic control in patients with diabetes and chronic kidney disease (CKD). Glycated albumin (GA) and fructosamine are alternative markers of glycaemia. The aim of this study was to investigate the accuracy of HbA1c, GA and fructosamine as indicators of glycaemic control using continuous glucose monitoring. Methods: HbA1c, GA and fructosamine concentrations were measured in 25 subjects with diabetic nephropathy (CKD stages 4 and 5 (estimated glomerular filtration rate <30 mL/min per 1.73 m²)) matched with 25 subjects with diabetes and no evidence of nephropathy. Simultaneous real‐time glucose concentrations were monitored by continuous glucose monitoring over 48 h. Results: GA correlated significantly to mean glucose concentrations in patients with and without CKD (r = 0.54 vs 0.49, P < 0.05). A similar relationship was observed with fructosamine relative to glucose. A poor correlation between HbA1c and glucose was observed with CKD (r = 0.38, P = ns) but was significant in the non‐CKD group (r = 0.66, P < 0.001). The GA/HbA1c ratio was significantly higher in diabetic patients with CKD compared with controls (2.5 ± 0.4 vs 2.2 ± 0.4, P < 0.05). HbA1c values were significantly lower in CKD patients, relative to non‐CKD patients at comparable mean glucose concentrations. Conclusion: HbA1c significantly underestimates glycaemic control in patients with diabetes and CKD stages 4 and 5. In severe CKD, GA more accurately reflects glycaemic control compared with fructosamine and HbA1c and should be the preferred marker of glycaemic control.     

Functional correlates of alpha(2A)-adrenoceptor gene polymorphism in the HANE study.

BACKGROUND: The aim of this study was to test an association between alleles of the alpha(2A)-adrenoceptor gene with hereditary hypertension and with alterations of lipid and carbohydrate metabolism. METHODS: Genomic DNA was isolated from 147 hypertensive patients and digested with DraI. Genotypes at the alpha(2A)-adrenoceptor were identified by restriction fragment length polymorphism. Genotype at each locus was related to blood pressure, family history of hypertension and various clinical chemistry parameters. RESULTS: The alpha(2A)-adrenoceptor polymorphism was not significantly associated with blood pressure or a family history of hypertension. Patients with the d allele of the alpha(2A)-adrenoceptor had significantly lower HbA(1) (5.6 vs 6.2%, P=0.0344) and HbA(1c) (3.4 vs 3.9%, P=0.0237) and total cholesterol (212 vs 229 mg/dl, P=0.0333) than those without. Similar trends, which failed to reach statistical significance, were seen for glucose, triglycerides and LDL cholesterol. CONCLUSIONS: We propose that alleles at the alpha(2A)-adrenoceptor locus might contribute to interindividual differences in the regulation of human lipid and glucose metabolism.     

Examination of Carbohydrate Metabolism Parameters After Simultaneous Pancreas-Kidney Transplantation

End-stage renal failure, a frequent complication of type 1 diabetes mellitus, requires renal replacement therapy. Our team examined the laboratory parameters of carbohydrate metabolism in 18 patients with type 1 diabetes at 10 to 89 months after simultaneous pancreas-kidney transplantation. We compared these results with those of 17 patients with type 1 diabetes who had formerly received kidney-alone transplantations, and were undergoing insulin treatment, as well as with those of 16 metabolically healthy controls. The hemoglobin A1c (HbA1c) and blood glucose levels of the pancreas-kidney transplant recipients were within the normal ranges, not differing significantly from those of the healthy controls. In contrast, the HbA1c and glucose levels were significantly elevated among kidney transplanted diabetic subjects. However, fasting and 2-hour insulin levels of pancreas-kidney transplant patients were significantly higher than those of the controls, indicating insulin resistance. According to these results, the insulin secretion by the pancreas graft sufficiently compensated for insulin resistance. Thus 10 to 89 months after successful pancreas-kidney transplantation, carbohydrate metabolism by type 1 diabetic patients was well controlled without antidiabetic therapy.     

Relationship of glycosylated hemoglobin to oral glucose tolerance. Implications for diabetes screening

The oral glucose tolerance test (OGTT) for diagnosis of diabetes is inconvenient and requires a great deal of patient cooperation. Glycosylated hemoglobin (GHb), an index of long-term glycemic control, could offer several practical advantages over the OGTT for diabetes screening. We evaluated GHb as a screen for diabetes in 381 adults from a population with a high prevalence of non-insulin-dependent diabetes (Pima Indians). All individuals underwent a standard OGTT (75 g) and were separated into one of three groups: normal (N), impaired glucose tolerance (IGT), or diabetes mellitus (D) based on World Health Organization criteria. HbA1c, a GHb, was measured by highly precise high-performance liquid chromatography (interassay C.V. less than 4%). The normal range for HbA1c was 4.07-6.03% based on the 95% confidence interval for a nondiabetic, mostly Caucasian population. Compared with OGTT, HbA1c was highly specific (91%); an elevated HbA1c usually indicated D or IGT (sensitivity = 85 and 30%, respectively). A normal HbA1c did not, however, exclude a diagnosis of D or IGT. Based on previous epidemiological studies relating plasma glucose to chronic diabetic complications, GHb as measured in this study would properly identify the vast majority of subjects at risk. Long-term studies are necessary to determine the actual risk of complications in individuals with persistently normal HbA1c and D or IGT (based on OGTT).     

Validity of glycated haemoglobin to diagnose new onset diabetes after transplantation

Diagnosing new onset diabetes after transplantation (NODAT) by glycated haemoglobin (HbA1c) has not been validated against the gold‐standard oral glucose tolerance test (OGTT). We analysed the predictive and optimum value of HbA1c to diagnose NODAT amongst nondiabetic renal transplant recipients. Assessment of glucose metabolism (OGTT and HbA1c) was prospectively undertaken at 3 and 12 months post‐transplantation in 71 nondiabetic renal transplant recipients. Receiver operator characteristic (ROC) curve analyses were performed to determine accuracy, sensitivity, specificity and area under curve (c‐statistic). Incidence of NODAT at 3 and 12 months post‐transplantation was 14.3% and 9.5% respectively. At 3 months, optimum HbA1c cut‐off value for predicting NODAT based on fasting glucose was 7.35 [AUC 1.00 (sensitivity 100.0%, specificity 100.0%, P = 0.004)] and for postprandial glucose‐defined NODAT was 6.20 [AUC 0.98 (sensitivity 100.0%, specificity 88.9%, P < 0.001)]. At 12 months, optimum HbA1c cut‐off value for both fasting‐ and postprandial glucose‐defined NODAT was 6.45 [AUC 0.92 (sensitivity 100.0%, specificity 87.5%, P = 0.048) and AUC 0.84 (sensitivity 75.0%, specificity 89.5%, P = 0.026) respectively]. Concordance between diagnosis of NODAT (OGTT+, HbA1c+) and nondiagnosis of NODAT (OGTT?, HbA1c?) was 88.9% and 98.7% respectively. To conclude, HbA1c (≥6.5%) can be utilized to diagnose NODAT beyond 3 months post‐transplantation but the OGTT remains the gold‐standard tool.