The role of post prandial hyperglycemia in contributing to the risk of macro
vascular complications in patients with diabetes mellitus is being increasingly
recognized. In type2 diabetes ,there is a progressive shift in the relative
contributions of postprandial & fasting hyperglycemia to the overall glycemic
control as the disease progress. For patients with fairly good glycemic control(
glycosylated hemoglobin[HbA1c] >8.5%) ,postprandial hyperglycemia makes a
relatively greater contribution to the overall glycemic load than fasting
hyperglycemia ,but in patients with poorer control the relative contribution of the
two states to the overall glycemic load is reversed. This finding coupled with
epidemiological evidence that elevated postprandial glucose concentration is an
independent risk factor for cardiovascular disease (C V D) ,and is associated with
a greater CVD risk than elevated fasting glucose , points to the need to monitor
and target postprandial glucose, as well as fasting glucose and HbA1C levels
,when optimizing insulin therapy for patients with type2 diabetes. HbA1C and
GA can be satisfactorily predicted by FBG and PPG. HbA1C reflects FBG more
than PPG, whereas GA better reflects PPG. Thus depending on the characteristics
of the glycated protein, a different glycemic status is reflected. Postprandial
glycaemia is a phenomenon often neglected by patients as well as doctors. It is
however undeniable that the postprandial glycemic excursion plays an important
role in total hyperglycemia reflected by an increase in glycated hemoglobin. The
postprandial glycaemia measurement or more appropriately the postprandial
glycemic excursion (the difference between postprandial and pre-prandial
glycaemia, also called the post prandial delta glycaemia), is important to measure
,and there are specific tools to correct it when abnormal. Post prandial delta
glycaemia should lie between 30 and 50 mg/ dl. It is thus suggested to measure it
not necessarily on a daily basis , but when it is expected that the glycemic couple,
or the pre-postprandial couple is high .The specific tools for treatment of
postprandial hyperglycemia can be dietetic (carbohydrate quantity reduction or
ingestion of fiber rich and /or low glycemic index foods) or medicinal. Among
the specific medicinal treatments are the alfa- glycosidase-inhibitors (which can
be used for both type1 and type2 diabetic patients ), glinides and fast acting
insulins . Rather than first treating fasting and interprandial hyperglycemia , as
has been commonly done by physicians, the authors recommend the simultaneous
treatment of pre, inter and postprandial hyperglycemia. The optimal time at
which to evaluate postprandial glycaemia is approximately 1h and 15 minutes for
type 1 and type 2 diabetic patients. The measurement of HbA1c concentrations is
considered the gold standard for assessing long term glycemic control at present
& is regarded as key therapeutic target for the prevention of diabetesrelatedcomplication.TheHbA1cconcentration ,although a useful measure of
metabolic control and the efficacy of diabetes therapeutic interventions, is an
integrated summary of circadian blood glucose concentrations during the
receding 6-8 weeks. It therefor does not reverse any information on the extent or
frequency of blood glucose excursions but provide an overall mean value only .
This being the case, one can argue that the HbA1c concentration is not
necessarily the best or the most clinical useful glycemic indicator of risk of
complications, particularly at the lower end of elevated HbA1c concentrations.
For instance in patients ,in whom glucose concentration fluctuate markedly, the HbA1c may indicate adequate metabolic control ;however ,such patients are
exposed to the risks of hypoglycemia and the possibly harmful effects of
excessive postprandial hyperglycemic excursion. HbA1c is an easily measured
biochemical marker that strongly correlates with the level of ambient glycemia
during a 2-3 –mo period . Tests for HbA1c are also expensive and can be done at
any time of a day . The concentration of HbA1c predicts the ris of incident eye,
kidney, and nerve disease in persons with type 1 and type 2 diabetes mellitus.
Epidemiologic evidence also indicates that HbA1c is a progressive risk factor for
cardiovascular disease in both persons with diabetes and those without diabetes.
Glycated Albumin has been reported as a rapid and useful indicator of glycemic
control since the turnover of serum albumin is much shorter (half life of 17 days)
than that of HbAIc. Circulating albumin is strongly glycated at 4 sites of lysine
residues and the glycation reaction occurs ten times more than in HbA1c. Human
Serum Albumin is very sensitive to glycation , the slow, non-enzymatic (Maillard
reaction) initially involves the attachment of glucose or other carbohydrate
compounds such as galactose and fructose, to the free amine groups of albumin. |
