Postprandial and basal glucose in type 2 diabetes: assessment and respective impacts

Stepwise intensification of insulin therapy in type 2 diabetes management--exploring the concept of the basal-plus approach in clinical practice

Basal insulin provides an effective method for initiating insulin therapy in people with Type 2 diabetes, resulting in significant improvements in glycaemic control, lower rates of hypoglycaemia and less weight gain than either prandial or premixed insulin regimens. However, the progressive nature of Type 2 diabetes and the inability of basal insulin to correct excessive postprandial glucose excursions mean that insulin therapy will eventually need to be intensified, typically by adding prandial insulin as part of a basal-bolus or premixed insulin regimen. The aim of this review is to summarize recent clinical evidence for a staged 'basal-plus' strategy for insulin intensification where one, two or three prandial insulin injections are added to basal insulin according to individual need. In the early stages of insulin therapy, most individuals seem to achieve favourable glycaemic control with basal insulin alone, or in combination with a single prandial insulin injection. The addition of a single prandial insulin injection at the largest meal is well tolerated and associated with significant improvements in glycated haemoglobin (HbA(1c)), low rates of hypoglycaemia and limited weight gain. More people achieve recommended HbA(1c) targets with a basal-plus strategy, compared with twice-daily premixed insulin therapy, with lower rates of hypoglycaemia. The data indicate that a step-by-step approach with the basal-plus strategy is a promising alternative method of insulin intensification that allows for individualization of treatment and may delay progression to a full basal-bolus insulin replacement therapy for many individuals.

Assessment of postprandial glucose excursions throughout the day in newly diagnosed type 2 diabetes

BACKGROUND

A growing body of evidence suggests that postprandial glucose (PPG) is independently linked to multiple complications and that testing of PPG should be added to hemoglobin A1c (HbA1c) and fasting glucose measurements in the evaluation of glycemic control of type 2 diabetes patients. An ongoing debate is questioning how to assess PPG. This observational study looks further into this question in a cohort of newly diagnosed type 2 diabetes patients.

SUBJECTS AND METHODS

PPG characteristics and intra-/intersubject variations post-breakfast, -lunch, and -dinner, obtained from continuous glucose monitoring (CGM), were retrospectively analyzed in 86 newly diagnosed non-insulin-treated type 2 diabetes patients.

RESULTS

In total, 462 recorded meals were analyzed. The area under the curve 1-4 h postmeal was significantly larger after breakfast compared with both lunch and dinner (P<0.001). Time to peak was approximately 90 min and did not differ significantly between meals. However, the distribution of the blood glucose peaks was only normally distributed among breakfasts, and time to peak had a day-to-day correlation coefficient of 0.60, compared with a nonsignificant result for lunch and dinner. Breakfast PPG peaks were highly correlated to HbA1c (P<0.05, r=0.64) and had a day-to-day correlation coefficient of 0.86 compared with 0.44 for lunch and 0.74 for dinner.

CONCLUSIONS

Self-monitoring of blood PPG should be evaluated with care. From our data, monitoring of PPG patterns in newly diagnosed type 2 diabetes patients should preferably be obtained following breakfast for a more consistent assessment, reducing day-to-day variations.

Add-on therapies to metformin in type 2 diabetes: what modulates the respective decrements in postprandial and basal glucose?

BACKGROUND

Oral hypoglycemic agents (OHAs) are usually divided into postprandial and basal drugs. As their actions are probably more complex, it is important to ascertain which factors can modulate their effects.

SUBJECTS AND METHODS

Thirty-one type 2 diabetes patients treated with metformin (glycosylated hemoglobin [HbA1c] 6.5-9%; median, 7.3%) and enrolled in two randomized controlled studies were allocated to either rosiglitazone (Group 1, n = 8) or glimepiride (Group 2, n = 7) and to either vildagliptin or sitagliptin (Group 3 considered as a whole, n = 16). All patients were investigated using continuous glucose monitoring at baseline and after 8-12 weeks of add-on therapy. Areas under the 24-h glycemic profile curves (AUCs) were determined for assessing postprandial (AUCpp), basal (AUCb), and total (AUCtotal) hyperglycemia. After calculation of decrements in AUCs (∂AUCs) from baseline to end of treatment periods, the following contribution ratios of postprandial and basal decrements to the overall glucose decrement were determined: ∂AUCpp/∂AUCtotal and ∂AUCb/∂AUCtotal (%).

RESULTS

∂AUCpp/∂AUCtotal and ∂AUCb/∂AUCtotal were negatively and positively, respectively, associated (R(2) = 0.195, P = 0.013) with baseline HbA1c. ∂AUCpp/∂AUCtotal was significantly higher (50.8 ± 4.8%) in patients with HbA1c <7.3% than in those with HbA1c ≥ 7.3% (27.0 ± 4.4%) (P = 0.001). After adjustment on baseline HbA1c, ∂AUCpp/∂AUCtotal was greater in Group 3 (44.0 ± 1.6%) than in Group 1 (32.1 ± 4%) and 2 (37.0 ± 3.1%) (P = 0.007).

CONCLUSIONS

Gliptins, glitazones and sulfonylureas concomitantly act on basal and postprandial glucose even though gliptins are more efficient on postprandial glucose. HbA1c appears as a reliable factor for predicting the respective decrements of these two parameters and thus for guiding the choice between the aforementioned drugs.

The glycemic triumvirate and diabetic complications: is the whole greater than the sum of its component parts?

The dysglycemia of diabetes mellitus can be depicted as the glycemic triumvirate with its 3 main components: the sustained chronic (ambient) hyperglycemia, glucose variability and hypoglycemic episodes. The respective contributions of these glycemic disorders to the overall risk for diabetic complications remain a subject of debate. At present, there is cogent evidence for the direct deleterious effect of ambient hyperglycemia while the roles exerted by glucose variability and hypoglycemia remain less documented and only based on observational and pathophysiological studies. In addition, these 3 glycemic disorders could be regarded as components of either an additive or an initiator/accelerator model according to whether each disorder exerts an independent or inter-dependent effect on the development and progression of diabetes-related complications, respectively. In the present review, pros and cons arguments for each model are debated. However it is highly likely that these 3 glycemic disorders have both direct (spoke in a wheel) and indirect (link in a chain) causal effects on clinical cardiovascular outcomes. As a consequence, the relationship between the so-called glycemic triumvirate and diabetic complications might be summarized by the famous Aristotle's aphorism: "the whole is greater than the sum of its parts".

Insulin therapy in type 2 diabetes mellitus

Health care providers and patients have lots of choice to treat type 2 diabetes, but the blood glucose improvement is limited. The one therapy with unlimited potential (at least theoretically) is insulin. Many studies show that glucose control is achievable with insulin safely in most patients with type 2 diabetes. Effective diabetes management at the primary care or specialty level requires a belief in the importance of insulin therapy in uncontrolled patients with type 2 diabetes. This review details the theories, observed outcomes, and how-tos regarding insulin use in type 2 diabetes.

Contributions of basal and postprandial hyperglycemia over a wide range of A1C levels before and after treatment intensification in type 2 diabetes

OBJECTIVE

To determine the relative contributions of basal hyperglycemia (BHG) versus postprandial hyperglycemia (PPHG) before and after treatment intensification in patients with glycated hemoglobin A(1c) (A1C) >7.0% while on prior oral therapy.

RESEARCH DESIGN AND METHODS

Self-measured, plasma-referenced glucose profiles and A1C values were evaluated from participants in six studies comparing systematically titrated insulin glargine with an alternative regimen (adding basal, premixed, or prandial insulin, or increasing oral agents). Hyperglycemic exposure (>100 mg/dL [5.6 mmol/L]) as a result of BHG versus PPHG was calculated.

RESULTS

On prior oral therapy, 1,699 participants (mean age 59 years, diabetes duration 9 years) had mean fasting plasma glucose (FPG) of 194 mg/dL (10.8 mmol/L), and mean A1C was 8.7%. BHG contributed an average of 76-80% to hyperglycemia over the observed range of baseline A1C levels. Adding basal insulin for 24 or 28 weeks lowered mean FPG to 117 mg/dL (6.5 mmol/L), A1C to 7.0%, and BHG contribution to 32-41%. Alternative regimens reduced FPG to 146 mg/dL (8.1 mmol/L), A1C to 7.1%, and the contribution of BHG to 64-71%. BHG contributions for patients with A1C averaging 7.6-7.7% were 76% at baseline and 34 and 68% after adding basal insulin or other therapies, respectively.

CONCLUSIONS

When A1C is >7.0% despite oral therapy, BHG routinely dominates exposure. Intensified therapy reduces A1C and changes this relationship, but BHG amenable to further intervention still accounts for one-third of total hyperglycemia after basal insulin treatment and two-thirds after alternative methods.