Altered fructosamine and lipid fractions in subclinical hypothyroidism

Fructosamine and HbA1c: A Correlational Study in a Southeast Asian Population

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.

Methods

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.

Changes of Certain Metabolic and Cardiovascular Markers Fructosamine, H-FABP and Lipoprotein (a) in Patients with Hypothyroidism

Background:

Disorders of thyroid gland are common in general population, and it’s the most common affecting the endocrine system after diabetes mellitus. Thyroid function regulates a wide range of metabolic parameters, as well as affects some cardiovascular disease risk factors. Fructosamine is produced by a reaction between albumin (protein) and glucose; it is used to monitor patients with diabetes for short-term glycemic changes. H-FABP is present in the cytoplasm of cardiac myocytes, and delivers fatty acids into these cells. It has been shown to increase in myocardial injury. Lipoprotein LP(a) is consist of a special apolipoprotein called apoprotein (a), and it’s recognized as a cardiovascular disease independent risk factor.

Objective:

To study whether certain metabolic and cardiovascular markers (fructosamine, H-FABP and lipoprotein (a) are changed in hypothyroid patients.

Methods:

The current study included 280 overt hypothyroid, 272 with subclinical hypothyroidism compared with 270 healthy individuals of matched age and gender. For all subjects serum (TSH, T4, T3, FBS, HbA1c, fructosamine, triglycerides, cholesterol, lipoprotein (a), and Heart-type Fatty Acid-Binding Protein (H-FABP)) was measured.

Results:

Serum fructosamine level significantly elevated (p value <0.05) in patient with hypothyroidism when compared with control group, and no significant change between subclinical and control groups. There is no significant change in serum H-FABP between study subjects. There is significant increase in lipoprotein (a) in patient with hypothyroidism and those with subclinical group when compared with control group.

Conclusion:

Serum fructosamine and level is significantly changed in patients with overt hypothyroidism when compared with euthyroid subjects. Also, we conclude that hypothyroidism increase risk of cardiovascular diseases by changing non-traditional marker such as lipoprotein (a), and no effect on H-FABP concentration.

Inherent suppression of thyroid stimulating hormone in newly diagnosed dyslipidemic patients - indication for use of thyromimetics?

BACKGROUND

Dyslipidemia triggers a sequel of metabolic derangements such as insulin resistance, hyperglycemia and oxidative stress via vicious cycle. Dyslipidemia is characterised by elevation of plasma cholesterol, triglycerides (TGs), or both, or a low level of high-density lipoprotein (HDL) which in turn can progress to atherosclerosis a forerunner for ischemic heart disease (IHD). Dyslipidemia is seen even in subclinical hypothyroid patients.

OBJECTIVES

The aim of the study was to look for thyroid & glycemic abnormalities in dyslipidemic patients and compare it with euthyroid, normolipidemic group.

MATERIALS AND METHODS

Thirty primarily dyslipidemic patients and 30 euthyroid normolipidemic subjects aged 25-55 years were tested for fasting plasma glucose (FPG), fructosamine, lipid profile, thyroid hormones - T3, T4 and thyroid stimulating hormone (TSH). The values were compared with those of age matched euthyroid normolipidemic control group.

RESULTS

The dyslipidemic pool showed small but significant decrease in the TSH levels with comparable T3, T4 levels as compared to euthyroid group. The group also had significantly higher FPG, total cholesterol (TC), triglycerides (TG), low density lipoprotein (LDL) levels and lower high density lipoprotein (HDL) levels as compared to the euthyroid normolipidemic group. The plasma fructosamine levels were similar in both the groups. The observed results reflected a picture of subclinical hyperthyroidism in dyslipidemic patients.

CONCLUSION

The observations of the present study preclude a need to assess the thyroid status in patients of primary dyslipidemia as both conditions per se have an increased risk of cardio vascular diseases. A subclinical hyperthyroid state may essentially be helpful in maintaining the lipid metabolism. The prevailing mild hyperthyroid status also makes it important to reconsider the accuracy of long term glycemic indicators like fructosamine and possibly glycated haemoglobin in these patients. Upon establishment of their efficacy and safety, thyromimetics may have a role in the treatment of dyslipidemia.