Serum fructosamine and risk of cardiovascular and all-cause mortality: a 24-year prospective population-based study

1-Amino-1-deoxy-d-fructose ("fructosamine") and its derivatives: An update

1-Amino-1-deoxy-d-fructose (fructosamine, FN) derivatives are omnipresent in all living organisms, as a result of non-enzymatic condensation and Amadori rearrangement reactions between free glucose and biogenic amines such as amino acids, polypeptides, or aminophospholipids. Over decades, steady interest in fructosamine was largely sustained by its role as a key intermediate structure in the Maillard reaction that is responsible for the organoleptic and nutritional value of thermally processed foods, and for pathophysiological effects of hyperglycemia in diabetes. New trends in fructosamine research include the discovery and engineering of FN-processing enzymes, development of advanced tools for hyperglycemia monitoring, and evaluation of the therapeutic potential of both fructosamines and FN-recognizing proteins. This article covers developments in the field of fructosamine and its derivatives since 2010 and attempts to ascertain challenges in future research.

Association of Alternative Markers of Carbohydrate Metabolism (Fructosamine and 1,5-Anhydroglucitol) with Perioperative Characteristics and In-Hospital Complications of Coronary Artery Bypass Grafting in Patients with Type 2 Diabetes Mellitus, Prediabetes, and Normoglycemia

Patients with type 2 diabetes make up 25 to 40% of those referred for coronary bypass surgery, and the impact of diabetes on the results of the operation is studied in various aspects. To assess the state of carbohydrate metabolism before any surgical interventions, including CABG, daily glycemic control, and the determination of glycated hemoglobin (HbA1c) is recommended. Glycated hemoglobin reflects the glucose concentration for the 3 months prior to the measurement, but alternative markers that reflect glycemic fluctuations over a shorter period of time may be useful in preoperative preparation. The aim of this study was to study the relationship between the concentration of alternative markers of carbohydrate metabolism (fructosamine and 1,5-anhydroglucitol) with patients' clinical characteristics and the rate of hospital complications after coronary artery bypass grafting (CABG).

METHOD

In the cohort of 383 patients, besides the routine examination, additional markers of carbohydrate metabolism were determined before and on days 7-8 after CABG: glycated hemoglobin (HbA1c), fructosamine, and 1,5-anhydroglucitol. We evaluated the dynamics of these parameters in groups of patients with diabetes mellitus, prediabetes, and normoglycemia, as well as the association of these parameters with clinical parameters. Additionally, we assessed the incidence of postoperative complications and factors associated with their development.

RESULTS

In all groups of patients (diabetes mellitus, prediabetes, normoglycemia), there was a significant decrease in the level of fructosamine on the 7th day after CABG compared with baseline (p1st-2nd point 0.030, 0.001, and 0.038 in groups 1, 2, and 3, respectively), whereas the level of 1,5-anhydroglucitol did not change significantly. The preoperative level of fructosamine was associated with the risk of surgery according to the EuroSCORE II scale (p = 0.002), as were the number of bypasses (p = 0.012), body mass index and overweightness (p < 0.001 in both cases), triglyceride (p < 0.001) and fibrinogen levels (p = 0.002), preoperative and postoperative glucose and HbA1c levels (p < 0.001 in all cases), left atrium size (p = 0.028), multiplicity of cardioplegia, cardiopulmonary bypass duration and aortic clamp time (p < 0.001 in all cases). The preoperative level of 1,5-anhydroglucitol showed an inverse correlation with fasting glucose and fructosamine levels before surgery (p < 0.001 in all cases), intima media thickness (p = 0.016), and a direct correlation with LV end-diastolic volume (p = 0.020). The combined endpoint (presence of significant perioperative complications + extended hospital stay after surgery >10 days) was identified in 291 patients. In binary logistic regression analysis patient age (p = 0.005) and fructosamine level (p = 0.022) were independently associated with the development of this composite endpoint (presence of significant perioperative complications + extended hospital stay after surgery >10 days).

CONCLUSIONS

This study demonstrated that in patients after CABG there was the significant decrease in the level of fructosamine compared with baseline, whereas the level of 1,5-anhydroglucitol did not change. Preoperative fructosamine levels were one of the independent predictors of the combined endpoint. The prognostic value of preoperative assessment of alternative markers of carbohydrate metabolism in cardiac surgery deserves further study.

1,5-Anhydroglucitol as a Marker of Acute Hyperglycemia in Cardiovascular Events

1,5-anhydroglucitol (1,5-AG) is a biomarker of acute hyperglycemia in diabetology and also in cardiodiabetology. It is used to monitor fluctuating glucose levels. 1,5-AG is a monosaccharide that is biochemically similar to D-glucose and originates from the nutrition. The presence of 1,5-AG in blood and tissue is nearly constant due to reabsorption in the renal proximal tubule. In acute hyperglycemia, renal reabsorption is inhibited by glucose and 1,5- AG is excreted in the urine, while its serum level decreases rapidly. 1,5-AG reflects glucose excursions over 1-3 days to 2 weeks. In this regard, low levels of serum 1,5-AG can be a clinical marker of short- term glycemic derangements such as postprandial hyperglycemia, which is an important risk factor for the pathogenesis of coronary artery disease (CAD) as low levels of 1,5-AG reflect severe plaque calcification in CAD and correlate with high-density lipoprotein cholesterol (HDL-C) levels. For these reasons, 1,5-AG may also be a marker for atherosclerosis; in fact an even better marker than HbA1c or fructosamine which are normally used. 1,5-AG may also be a predictor of cardiovascular disease, left ventricular dysfunction after acute coronary syndrome (ACS), and mortality after ACS. This articles reviews the current knowledge on 1,5-AG related to its use as predictor for cardiovascular events.

The relationships between serum fructosamine concentrations and lipid profiles in community-dwelling adults

We examined the epidemiological associations between serum fructosamine and dyslipidemia indices in community-dwelling adults. Clinical characteristics and lipid profiles were analyzed in 1352 community-dwelling adults. The demographic characteristics and laboratory results were grouped according to the quartiles of serum fructosamine concentrations in all eligible individuals. From the bottom to the top quartile of serum fructosamine, there were graded increases in age, total cholesterol (TC), fasting blood glucose (FBG), total protein (TP), triglyceride (TG), total cholesterol/ high density lipoprotein-cholesterol (TC/HDL-C) and atherogenic index of plasma (AIP). Serum fructosamine was positive correlated with age, TC, FBG, TP, TG, TC/HDL-C and AIP in whole individuals. The positive correlations were then observed in both genders between serum fructosamine and TC, FBG, TP, TG. Two dominant factors were identified by principal component analysis. Logistic regression analysis showed that the two factors were associated with increased serum fructosamine with adjustment for gender, age, body mass index (BMI), FBG and TP. The similar results were observed in males, but not in females. Dyslipidemia tends to contribute to increased serum fructosamine concentrations in study population, suggesting that elevated serum fructosamine may herald an increased risk of cardiovascular disease among community-dwelling adults, especially in males.

Low fructosamine and mortality - A long term follow-up of 215,011 non-diabetic subjects in the Swedish AMORIS study

BACKGROUND AND AIMS

Both high and low fasting glucose has been associated with an increased mortality among individuals without diabetes. This J-shaped association has also been shown for HbA1c in relation to all-cause mortality. High fructosamine is associated with increased mortality. In this study we aim to evaluate if low fructosamine is also associated with increased mortality in non-diabetic subjects.

METHODS AND RESULTS

We included 215,011 subjects from the AMORIS cohort undergoing occupational health screening or primary care in Stockholm, Sweden. Cause specific mortality was obtained from the Swedish Cause-of-Death Register by record linkage. Hazard ratios for the lowest decile of fructosamine were estimated by Cox regression for all-cause (n = 41,388 deaths) and cause-specific mortality during 25 years of follow-up. We observed gradually increased mortality with lower fructosamine in a large segment of the population. In the lowest decile of fructosamine the sex, age, social class and calendar adjusted hazard ratio was 1.20 (95% CI; 1.18-1.27) compared to deciles 2-9. This increased mortality was attenuated after adjustment for six other biomarkers (HR = 1.11 (95% CI; 1.07-1.15)). Haptoglobin, an indicator of chronic inflammation, made the greatest difference in the point estimate. In sensitivity analyses we found an association between low fructosamine and smoking and adjustment for smoking further attenuated the association between low fructosamine and mortality.

CONCLUSION

Low levels of fructosamine in individuals without diabetes were found to be associated with increased mortality. Smoking and chronic inflammation seem to at least partially explain this association but an independent contribution by low fructosamine cannot be excluded.