Effect of acute blood loss on glycosylated hemoglobin determinations in normal subjects

Autoimmune liver diseases and diabetes

Autoimmune liver diseases include autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis. They are chronic, heterogenous diseases affecting the liver which is a key metabolic organ that ensures glucose homeostasis. It is well known that patients with other chronic liver diseases such as cirrhosis and nonalcoholic fatty liver disease (NAFLD) display glucose disturbances like insulin resistance and have an increased risk of diabetes. Previous evidence on glucose disturbances in patients with autoimmune liver disease is scarce but does point towards a potentially increased risk of type 1 diabetes and type 2 diabetes. The underlying mechanisms are unknown but may reflect genetic predisposition, concurrent NAFLD and or cirrhosis development, and treatment (steroid) related impairment of glucose homeostasis. Therefore, increased awareness and surveillance of diabetes development in patients with autoimmune liver disease may be important. Overall, detection and treatment of diabetes generally follow the usual diabetes guidelines; however, in patients with advanced liver cirrhosis, HbA1c may not be a reliable marker of average glucose levels, and treatment with insulin is generally recommended. In addition, it has recently been suggested that sodium-glucose cotransporter 2 inhibitors may be beneficial in treating refractory ascites. Further research on diabetes risk in autoimmune liver disease is warranted.

Influence of iron deficiency on Hb A1c levels in type 2 diabetic patients

AIMS

Hemoglobin A1c (HbA1c) is gold-standard for the assessment of glycemic control in diabetic patients. Previous studies have reported that iron deficiency may elevate A1c concentrations, independent of glycemia. This study aimed to analyze the effect of iron status on HbA1c levels in diabetic patients.

METHODS

661 patients 336 females (228 menopausal and 108 premenopausal) and 325 males (237 age> 50 years and 88 age < 50 years) were recruited. HbA1c, ferritin, fasting plasma glucose, hemogram and medical history were recorded. Analysis of variance ANOVA and Pearson's regression were applied.

RESULTS

patients were divided according gender, age, glycemia and iron status (normal, latent iron deficiency LID, iron deficiency anemia IDA).All groups presented increasing HbA1c values in parallel with iron deficiency, subclinical and anemia, but the level of significance was not homogeneous in the different groups. Controlled premenopausal women HbA1c in normal iron status and IDA groups P = 0.0048, between normal and LID, P = 0.033. Not controlled premenopausal women Normal group and IDAP < 0.001, normal iron status and LID P = 0.019. Controlled menopausal women normal group and IDAP < 0.0001, LID and IDA P = 0.01. Not controlled menopausal women normal group and IDA P = 0.04. Controlled men over 50 years normal and IDA groups P = 0.002, LID and IDA P = 0.02. Controlled young men normal group and LID P = 0.03.

CONCLUSION

This study found a positive correlation between iron deficiency and increased HA1c levels. In diabetic patients with IDA should be interpreted with caution, due to the possibility of spurious increment in HbA1c.

Challenges in diagnosing and monitoring diabetes in patients with chronic liver diseases

The prevalence and mortality of diabetes mellitus and liver disease have risen in recent years. The liver plays an important role in glucose homeostasis, and various chronic liver diseases have a negative effect on glucose metabolism with the consequent emergence of diabetes. Some aspects related to chronic liver disease can affect diagnostic tools and the monitoring of diabetes and other glucose metabolism disorders, and clinicians must be aware of these limitations in their daily practice. In cirrhotic patients, fasting glucose may be normal in up until 23% of diabetes cases, and glycated hemoglobin provides falsely low results, especially in advanced cirrhosis. Similarly, the performance of alternative glucose monitoring tests, such as fructosamine, glycated albumin and 1,5-anhydroglucitol, also appears to be suboptimal in chronic liver disease. This review will examine the association between changes in glucose metabolism and various liver diseases as well as the particularities associated with the diagnosis and monitoring of diabetes in liver disease patients. Alternatives to routinely recommended tests will be discussed.

Whole Blood Donation Affects the Interpretation of Hemoglobin A1c

Introduction

Several factors, including changed dynamics of erythrocyte formation and degradation, can influence the degree of hemoglobin A_1c (HbA_1c) formation thereby affecting its use in monitoring diabetes. This study determines the influence of whole blood donation on HbA_1c in both non-diabetic blood donors and blood donors with type 2 diabetes.

Methods

In this observational study, 23 non-diabetic blood donors and 21 blood donors with type 2 diabetes donated 475 mL whole blood and were followed prospectively for nine weeks. Each week blood samples were collected and analyzed for changes in HbA_1c using three secondary reference measurement procedures.

Results

Twelve non-diabetic blood donors (52.2%) and 10 (58.8%) blood donors with type 2 diabetes had a significant reduction in HbA_1c following blood donation (reduction >-4.28%, P < 0.05). All non-diabetic blood donors with a normal ferritin concentration predonation had a significant reduction in HbA_1c. In the non-diabetic group the maximum reduction was -11.9%, in the type 2 diabetes group -12.0%. When eligible to donate again, 52.2% of the non-diabetic blood donors and 41.2% of the blood donors with type 2 diabetes had HbA_1c concentrations significantly lower compared to their predonation concentration (reduction >-4.28%, P < 0.05).

Conclusion

Patients with type 2 diabetes contributing to whole blood donation programs can be at risk of falsely lowered HbA_1c. This could lead to a wrong interpretation of their glycemic control by their general practitioner or internist.

Effect of iron deficiency anemia on hemoglobin A1c levels

BACKGROUND

Iron deficiency anemia is the most common form of anemia in India. Hemoglobin A1c (HbA1c) is used in diabetic patients as an index of glycemic control reflecting glucose levels of the previous 3 months. Like blood sugar levels, HbA1c levels are also affected by the presence of variant hemoglobins, hemolytic anemias, nutritional anemias, uremia, pregnancy, and acute blood loss. However, reports on the effects of iron deficiency anemia on HbA1c levels are inconsistent. We conducted a study to analyze the effects of iron deficiency anemia on HbA1c levels and to assess whether treatment of iron deficiency anemia affects HbA1c levels.

METHODS

Fifty patients confirmed to have iron deficiency anemia were enrolled in this study. HbA1c and absolute HbA1c levels were measured both at baseline and at 2 months after treatment, and these values were compared with those in the control population.

RESULTS

The mean baseline HbA1c level in anemic patients (4.6%) was significantly lower than that in the control group (5.5%, P<0.05). A significant increase was observed in the patients' absolute HbA1c levels at 2 months after treatment (0.29 g/dL vs. 0.73 g/dL, P<0.01). There was a significant difference between the baseline values of patients and controls (0.29 g/dL vs. 0.74 g/dL, P<0.01).

CONCLUSIONS

In contrast to the observations of previous studies, ours showed that HbA1c levels and absolute HbA1c levels increased with treatment of iron deficiency anemia. This could be attributable to nutritional deficiency and/or certain unknown variables. Further studies are warranted.

Clinical use of fructosamine in islet transplantation

Many islet transplant recipients have medical conditions that could interfere with the accuracy of HbA1c measurements (e.g., anemia/dapsone use). Fructosamine is less prone to have clinical interferences and reflects glucose control in a shorter period of time than HbA1c. This study aimed to validate fructosamine use in islet transplant subjects and to evaluate its effectiveness as a predictor for islet graft dysfunction. Thirty-three islet transplant recipients who had concomitant fructosamine and HbA1c data available were retrospectively analyzed. HbA1c, fructosamine, mean capillary blood glucose, and islet graft function (fasting C-peptide/glucose ratio) were assessed. There was a significant and positive association between fructosamine and HbA1c (p < 0.0001). Both variables were also positively associated with mean overall and fasting capillary glucose. Neither fructosamine nor HbA1c was shown by ROC analysis to significantly discriminate between periods with and without subsequent graft dysfunction. HbA1c >6% was predictive of this outcome 1 month in advance (OR 2.95, p = 0.003). However, although significantly associated with graft dysfunction, use of this cutoff as a predictor of dysfunction has poor sensitivity (50%) and specificity (77.6%). Fructosamine above the normal range (>270 mumol/L Quest Diagnostics) was also predictive of ensuing dysfunction (OR 2.47, p = 0.03); however, it had similarly poor sensitivity (62%) and specificity (64%). Fructosamine can be used as an alternative to HbA1c for glycemic assessment in islet transplant recipients in situations with HbA1c assay interference. Neither HbA1c nor fructosamine are good predictors of islet graft dysfunction.