Global assessment for quality and safety of control in type 2 diabetic patients

Glycemic Variability: Assessing Glycemia Differently and the Implications for Dietary Management of Diabetes

The primary therapeutic target for diabetes management is the achievement of good glycemic control, of which glycated hemoglobin (HbA1c) remains the standard clinical marker. However, glycemic variability (GV; the amplitude, frequency, and duration of glycemic fluctuations around mean blood glucose) is an emerging target for blood glucose control. A growing body of evidence supports GV as an independent risk factor for diabetes complications. Several techniques have been developed to assess and quantify intraday and interday GV. Additionally, GV can be influenced by several nutritional factors, including carbohydrate quality, quantity; and distribution; protein intake; and fiber intake. These factors have important implications for clinical nutrition practice and for optimizing blood glucose control for diabetes management. This review discusses the available evidence for GV as a marker of glycemic control and risk factor for diabetes complications. GV quantification techniques and the influence of nutritional considerations for diabetes management are also discussed.

Starting or switching to biphasic insulin aspart 30 (BIAsp 30) in type 2 diabetes: a multicenter, observational, primary care study conducted in Finland

AIMS

Assess safety and glycaemic control in patients initiating insulin with, or switching from basal insulin to, biphasic insulin aspart 30/70 (BIAsp 30) in primary care in Finland.

METHODS

A non-randomised, non-interventional, open-label, 26-week study of type 2 diabetes (T2D) patients prescribed BIAsp 30 by their physician, who determined starting dose, titration and injection frequency.

RESULTS

496 patients provided safety data (insulin-naïve n=197; prior insulin n=299 [84.9% received NPH insulin]). Three patients (0.6%) reported four SADRs (three hypoglycaemia, one hypoglycaemia with unconsciousness). HbA1c was significantly (p<0.0001) reduced after 26 weeks' BIAsp 30 therapy (final dose): insulin-naïve -1.4% (44.4 IU); prior insulin -1.1% (77.4 IU). HbA1c<7.0% was achieved by 10% of insulin-naïve patients at baseline and 51% at 26-week follow-up. In the prior insulin group, 7% and 30% of patients had HbA1c<7.0% at baseline and 26 weeks, respectively. Minor hypoglycaemia increased significantly from baseline to study end: insulin-naïve 0.66-6.45 events/patient/year (p<0.0001); prior insulin 5.11-8.58 events/patient/year (p<0.05). Weight increased by 1.0 kg (insulin-naïve) and 1.3 kg (previous insulin).

CONCLUSION

BIAsp 30, initiated and titrated in T2D patients in primary care in Finland, showed a good safety profile and significantly improved glycaemic control.

Associations between features of glucose exposure and A1C: the A1C-Derived Average Glucose (ADAG) study

OBJECTIVE

Various methods are used to quantify postprandial glycemia or glucose variability, but few have been compared and none are standardized. Our objective was to examine the relationship among common indexes of postprandial glycemia, overall hyperglycemia, glucose variability, and A1C using detailed glucose measures obtained during everyday life and to study which blood glucose values of the day provide the strongest prediction of A1C.

RESEARCH DESIGN AND METHODS

In the A1C-Derived Average Glucose (ADAG) study, glucose levels were monitored in 507 participants (268 type 1 diabetic, 159 type 2 diabetic, and 80 nondiabetic subjects) with continuous glucose monitoring (CGM) and frequent self-monitoring of blood glucose (SMBG) during 16 weeks. We calculated several indexes of glycemia and analyzed their intercorrelations. The association between glucose measurements at different times of the day (pre- and postprandial) and A1C was examined using multiple linear regression.

RESULTS

Indexes of glucose variability showed strong intercorrelation. Among postprandial indexes, the area under the glucose curve calculated from CGM 2 h after a meal correlated well with the 90-min SMBG postprandial measurements. Fasting blood glucose (FBG) levels were only moderately correlated with indexes of hyperglycemia and average or postprandial glucose levels. Indexes derived with SMBG strongly correlated with those from CGM. Some SMBG time points had a stronger association with A1C than others. Overall, preprandial glucose values had a stronger association with A1C than postprandial values for both diabetes types, particularly for type 2 diabetes.

CONCLUSIONS

Indexes of glucose variability and average and postprandial glycemia intercorrelate strongly within each category. Variability indexes are weakly correlated with the other categories, indicating that these measures convey different information. FBG is not a clear indicator of general glycemia. Preprandial glucose values have a larger impact on A1C levels than postprandial values.

Glucose metabolism and hyperglycemia

Islet dysfunction and peripheral insulin resistance are both present in type 2 diabetes and are both necessary for the development of hyperglycemia. In both type 1 and type 2 diabetes, large, prospective clinical studies have shown a strong relation between time-averaged mean values of glycemia, measured as glycated hemoglobin (HbA1c), and vascular diabetic complications. These studies are the basis for the American Diabetes Association's current recommended treatment goal that HbA1c should be <7%. The measurement of the HbA1c concentration is considered the gold standard for assessing long-term glycemia; however, it does not reveal any information on the extent or frequency of blood glucose excursions, but provides an overall mean value only. Postprandial hyperglycemia occurs frequently in patients with diabetes receiving active treatment and can occur even when metabolic control is apparently good. Interventional studies indicate that reducing postmeal glucose excursions is as important as controlling fasting plasma glucose in persons with diabetes and impaired glucose tolerance. Evidence exists for a causal relation between postmeal glucose increases and microvascular and macrovascular outcomes; therefore, it is not surprising that treatment with different compounds that have specific effects on postprandial glucose regulation is accompanied by a significant improvement of many pathways supposed to be involved in diabetic complications, including oxidative stress, endothelial dysfunction, inflammation, and nuclear factor-kappaB activation. The goal of therapy should be to achieve glycemic status as near to normal as safely possible in all 3 components of glycemic control: HbA1c, fasting glucose, and postmeal glucose peak.

Traitement médicamenteux du diabète de type 2 (première partie)

Drug treatment of 2 diabetes is intended to normalize glycosylated hemoglobin levels (HbA(1c)<6.5%) and thereby prevent the development of micro- and macrovascular complications. Oral antidiabetic agents target the metabolic abnormalities that cause diabetes. The two principal families of oral antidiabetic agents - insulin sensitizers and insulin secretagogues - can be taken together. Thiazolidinediones or glitazones (insulin sensitizers) improve peripheral tissue sensitivity to insulin. Metformin (an insulin sensitizer) reduces hepatic glucose production. Sulfonylureas and meglitinides (insulin secretagogues) stimulate insulin secretion and can cause hypoglycemia. GLP-1 (Glucagon-Like Peptide-1) analogs and DPP-IV (dipeptidyl-peptidase-IV) inhibitors are new drug classes currently under development.

Self-monitoring of blood glucose and type 2 diabetes mellitus

Self-monitoring of blood glucose (SMBG) in management of type 2 diabetes mellitus continues to be debated. However, SMBG is recognized as being useful (professional agreement) in three situations: sensitizing the type 2 diabetic patient to the advantages of diet control and physical exercise, determining and adapting the dosage of oral antidiabetic medication at the beginning of treatment or during a dosage change, and monitoring plasma glucose during intercurrent disease or during a treatment that may lead to acute blood glucose imbalance. However, the frequency, the timing of blood glucose monitoring, and the target blood glucose values remain poorly defined. It is well known that the postprandial period covers approximately 50% of the day, and several recent studies have shown the respective role of fasting, pre- and postprandial glucose levels in overall diurnal hyperglycemia in the type 2 diabetic and their respective contribution to the mean HbA1c level depending on how well blood glucose levels are controlled. Based on these studies, it is now possible to propose a SMBG scheme, specific to a given patient and for a defined therapeutic objective, taking the three physiological periods into account: postprandial, postabsorptive, and fasting. However, the optimal use of SMBG requires patient education and training. Using a specific, adapted, and optimal SMBG is only advantageous if the results are usable, and used, by the patient and healthcare professionals to improve the quality of blood glucose control (as shown by the HbAlc level) and the safety of intensified oral antidiabetic treatments (minimal risk of hypoglycemia).

Postprandial glucose regulation: new data and new implications

BACKGROUND

Type 2 diabetes is characterized by a gradual decline in insulin secretion in response to nutrient loads; hence, it is primarily a disorder of postprandial glucose (PPG) regulation. However, physicians continue to rely on fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA1c) to guide management.

OBJECTIVES

The objectives of this article are to review current data on postprandial hyperglycemia and to assess whether, and how, management of type 2 diabetes should change to reflect new clinical findings.

METHODS

Articles were selected from MEDLINE searches (key words: postprandial glucose, postprandial hyperglycemia, and cardiovascular disease) and from our personal reference files, with emphasis on the contribution of postprandial hyperglycemia to overall glycemic load or cardiovascular (CV) risk.

RESULTS

About 33% of people diagnosed as having type 2 diabetes based on postprandial hyperglycemia have normal FPG. PPG contributes > or =70% to the total glycemic load in patients who are fairly well controlled (HbA1c <7.3%). Furthermore, there is a linear relationship between the risk of CV death and the 2-hour oral glucose tolerance test (OGTT). Increased mortality is evident at OGTT levels of approximately 90 mg/dL (5 mmol/L), which is well below current definitions of type 2 diabetes. Biphasic insulin aspart was shown to be more effective at reducing HbA1c below currently recommended levels than basal insulin glargine (66% vs 40%; P < 0.001), and it reduced endothelial dysfunction more effectively than regular insulin (P < 0.01). Repaglinide achieved regression of carotid atherosclerosis (intima-media thickness) in 52% of patients versus 18% for glyburide (P < 0.01) over 1 year, although levels of HbA1c and CV risk factors were similar for both treatment groups. Finally, acarbose reduced the relative risk of CV events by 49% over 3.3 years versus placebo in patients with impaired glucose tolerance (2.2% vs 4.7%; P = 0.03) and by 35% over > or =1 year in patients with type 2 diabetes (9.4% vs 6.1%; P = 0.006).

CONCLUSIONS

All components of the glucose triad (ie, FPG, HbA1c, and PPG) should be considered in the management of type 2 diabetes. Therapy targeted at PPG has been shown to improve glucose control and to reduce the progression of atherosclerosis and CV events; therefore, physicians should consider monitoring and targeting PPG, as well as HbA1c and FPG, in patients with type 2 diabetes.

Addition of rapid-acting insulin to basal insulin therapy in type 2 diabetes: indications and modalities

There are many reasons to believe that in the near future, the treatment of patients with Type 2 diabetes will be characterised by an increased use of insulin therapy. To ensure that insulin regimens are acceptable to patients, and implemented by physicians, they should be as simple and efficient as possible. Simplicity is synonymous with the regimen of once-daily basal insulin glargine given at any time of the day (at the same time each day). With such a strategy, the dose is adjusted by titrating to target fasting blood glucose values of 5.0 - 7.2 mmol/L (90 - 130 mg/dL). When these targets can no longer be achieved with reasonable doses of long-acting insulin, a rapid-acting insulin analogue should be added at meal times. A step-by-step strategy can be used; it is recommended that initially, a single daily prandial bolus of a rapid-acting insulin analogue is administered before the meal that leads to the highest post-meal blood glucose excursions. Further boluses can be added at other meal times as necessary, i.e, when post-meal blood glucose values remain above 10.0 mmol/L (180 mg/dL) and 7.8 mmol/L (140 mg/dL) at mid-morning and 2h-post-lunch or post-dinner times, respectively. This stepwise strategy may eventually lead to a standard basal-bolus regimen with 3 pre-meal injections of rapid-acting insulin analogues, a potentially small trade-off for achieving fairly-well controlled diabetes.

Contributions of Fasting and Postprandial Glucose to Hemoglobin A1c

OBJECTIVE

To define the respective contributions of fasting and postprandial plasma glucose to hemoglobin A1c (HbA1c) in patients with non-insulin-treated type 2 diabetes.

METHODS

Previous studies of diurnal glycemic profiles are reviewed, and glucose values for predicting successful treatment of diabetes are suggested.

RESULTS

By analyzing the results from prior studies of diurnal glycemic profiles, we found that the relative contribution of postprandial plasma glucose was high (70%) in patients with fairly good control of diabetes (HbA1c <7.3%) and decreased progressively (30%) with worsening diabetes (HbA1c >10.2%). In contrast, the contribution of fasting plasma glucose showed a gradual increase with increasing levels of HbA1c. By using the same model (the diurnal glycemic profile), we established that post-meal glycemia was a better predictor of good or satisfactory control of diabetes (HbA1c <7%) than was fasting glucose. The best cutoff values that ensured the optimal balance between high sensitivity and specificity were approximately 200 mg/dL at 11 AM and 160 mg/dL at 2 PM. The cut-point values for predicting treatment success (specificity (3) 90%) were 162 mg/dL at 11 AM and 126 mg/dL at 2 PM.

CONCLUSION

Postprandial plasma glucose is the predominant contributor in patients with satisfactory to good control of diabetes, whereas the contribution of fasting plasma glucose increases with worsening diabetes. Postmeal thresholds for predicting good or satisfactory control of diabetes are dependent on the timing of the meals.

Strategies for improving glycemic control: effective use of glucose monitoring

Despite the increasing prevalence of diabetes, improved understanding of the disease, and a variety of new medications, glycemic control does not appear to be improving. Self-monitoring of blood glucose (SMBG) is one strategy for improving glycemic control; however, patient adherence is suboptimal and proper education and follow-up are crucial. Patients need to understand why they are being asked to self-test, what their glycemic targets are, and what they should do based on the results of self-monitoring. Patients also must be taught proper technique and must be given specific recommendations regarding frequency and timing for self-monitoring. Situations in which SMBG is essential or should be more frequent include self-adjustment of insulin doses, changes in medications, lack of awareness of hypoglycemia, gestational diabetes, illness, or when hemoglobin A1c (HbA1c) values are above target. SMBG should include postprandial monitoring to identify glycemic excursions after meals, to indicate the need for lifestyle adjustments, and to provide patient feedback on dietary choices.

An overview of the rationale for pharmacological strategies in type 2 diabetes: from the evidence to new perspectives

Therapeutic strategies in type 2 diabetic patients should not only integrate both the targets and indications of the different therapies but should be also a compromise between the patient's and physician's goals and willingnesses. The rationale for therapeutic targets is based on recommendations that differ from one country to another. Even though HbA1c remains the "gold standard", monitoring of blood glucose at fasting and postprandial time-points is a complementary tool for estimating both the quality and safety of diabetic control. Despite the lack of available strong evidence-based data it seems that achieving glucose levels < 130 mg/dl at fasting and < 180 mg/dl or < 140 mg/dl over postbreakfast or postlunch periods, respectively, might be a reasonable goal in most countries. The choice of appropriate strategies for treating type 2 diabetic patients should ideally be based on pathophysiological considerations. However for practical reasons, decisions for initiating or completing antidiabetic treatments are usually made by using such simple parameters as HbA1c and plasma glucose levels. The bridge between pathophysiological and clinical rationales can be obtained from the analysis of the relative contributions of fasting and postprandial glucose to the overall hyperglycaemia. In patients with HbA1c < 7.3%, postprandial glucose makes the major contribution to the overall hyperglycaemia, whereas the contribution of fasting glucose becomes progressively predominant in patients with HbA1c > 7.3%. As a consequence of these observations, initiation of antidiabetic treatments or implementation of second-line therapies should be aimed at reducing either postprandial excursions or fasting hyperglycaemia according to whether HbA1c levels are found respectively below or above a cut-off value of 7.3%.

Self-monitoring of blood glucose in diabetic patients: from the least common denominator to the greatest common multiple

Self-monitoring of blood glucose (SMBG) is recognized as necessary in insulin-treated diabetic patients. There is less evidence for the regular use of SMBG in non-insulin-using type 2 diabetic patients. The rationale for an appropriate regimen of SMBG might be to have at least one time-point of monitoring included within each of the 3 periods of daytime i.e. fasting, postprandial and postabsorptive periods. Interventional trials have indicated that a 4-to 5-point daily profile represents an optimal regimen for SMBG in type 1 diabetic patients with satisfactory diabetic control. This type of SMBG includes 4 daily glucose determinations (3 before each meal and one at bedtime) and one weekly monitoring at 3: 00 am. However additional determinations should be made within postprandial states, particularly when rapid insulin analogues or pump-treatments are used. In non-insulin-using type 2 diabetic patients, studies of diurnal glycemic profiles have indicated that postprandial glucose is an important contributor to HbA1c and that mid-morning hyperglycemia is the "weakest link" of metabolic control. Therefore mid-morning glucose testing should be recommended when HbA1c levels are not correctly controlled. Furthermore, extended postlunch determinations at 5: 00 pm can be helpful for checking both the quality and safety of diabetic control in such patients. The frequency and timing of SMBG depend both on the type (1 or 2) of diabetes and should be a compromise between optimal and minimal regimens.