Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

Low-Dose Anti-Thymocyte Globulin (ATG) Preserves β-Cell Function and Improves HbA1c in New-Onset Type 1 Diabetes

OBJECTIVE

A pilot study suggested that combination therapy with low-dose anti-thymocyte globulin (ATG) and pegylated granulocyte colony-stimulating factor (GCSF) preserves C-peptide in established type 1 diabetes (T1D) (duration 4 months to 2 years). We hypothesized that 1) low-dose ATG/GCSF or 2) low-dose ATG alone would slow the decline of β-cell function in patients with new-onset T1D (duration <100 days).

RESEARCH DESIGN AND METHODS

A three-arm, randomized, double-masked, placebo-controlled trial was performed by the Type 1 Diabetes TrialNet Study Group in 89 subjects: 29 subjects randomized to ATG (2.5 mg/kg intravenously) followed by pegylated GCSF (6 mg subcutaneously every 2 weeks for 6 doses), 29 to ATG alone (2.5 mg/kg), and 31 to placebo. The primary end point was mean area under the curve (AUC) C-peptide during a 2-h mixed-meal tolerance test 1 year after initiation of therapy. Significance was defined as one-sided P value < 0.025.

RESULTS

The 1-year mean AUC C-peptide was significantly higher in subjects treated with ATG (0.646 nmol/L) versus placebo (0.406 nmol/L) (P = 0.0003) but not in those treated with ATG/GCSF (0.528 nmol/L) versus placebo (P = 0.031). HbA_1c was significantly reduced at 1 year in subjects treated with ATG and ATG/GCSF, P = 0.002 and 0.011, respectively.

CONCLUSIONS

Low-dose ATG slowed decline of C-peptide and reduced HbA_1c in new-onset T1D. Addition of GCSF did not enhance C-peptide preservation afforded by low-dose ATG. Future studies should be considered to determine whether low-dose ATG alone or in combination with other agents may prevent or delay the onset of the disease.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

The effect of basal-bolus therapy varies with baseline 1,5-anhydroglucitol level in people with Type 2 diabetes: a post hoc analysis

AIMS

To investigate the impact of baseline 1,5-anhydroglucitol on the treatment effect of basal-bolus therapy in people with Type 2 diabetes.

METHODS

Post hoc analysis of onset 3, an 18-week, randomized, phase 3 trial evaluating the efficacy and safety of fast-acting insulin aspart in basal-bolus therapy (n = 116) vs. basal insulin-only therapy (n = 120) in people with Type 2 diabetes. The estimated treatment difference in change from baseline in HbA1c was investigated for different cut-off values of baseline 1,5-anhydroglucitol (2, 3, 4, 5 and 6 μg/ml).

RESULTS

The estimated treatment difference in change from baseline in HbA1c between basal-bolus therapy and basal insulin-only therapy was statistically significantly greater in participants with baseline 1,5-anhydroglucitol ≤3 μg/ml (n = 34) vs. >3 μg/ml (n = 198) [estimated treatment difference (95% CI): -1.53% (-2.12; -0.94) vs. -0.82% (-1.07; -0.57); P-value for interaction = 0.03]. The estimated treatment difference became more pronounced when comparing participants with 1,5-anhydroglucitol ≤2 μg/ml (n = 15) vs. >2 μg/ml (n = 217) [estimated treatment difference (95% CI): -2.26% (-3.15; -1.36) vs. -0.85% (-1.08; -0.62); P-value for interaction = 0.003]. For cut-off values ≥4 μg/ml, estimated treatment differences were numerically greater below the cut-off compared with above, although the interaction terms were not statistically significant.

CONCLUSION

This analysis indicates that people with Type 2 diabetes with low 1,5-anhydroglucitol have an added treatment benefit with basal-bolus therapy compared with people with higher 1,5-anhydroglucitol. Further research is needed to clarify any clinical utility of these findings. Clinical Trials Registry No: NCT01850615.

Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Effect of adding insulin degludec to treatment in patients with type 2 diabetes inadequately controlled with metformin and liraglutide: a double-blind randomized controlled trial (BEGIN: ADD TO GLP-1 Study)

AIM

To evaluate the efficacy and safety of adding insulin degludec (IDeg) to treatment in patients with type 2 diabetes receiving liraglutide and metformin and qualifying for treatment intensification because of inadequate glycaemic control.

METHODS

In this 26-week, double-blind trial, patients who still had inadequate glycaemic control after a 15-week run-in period with initiation and dose escalation of liraglutide to 1.8 mg in combination with metformin (≥1500 mg) were randomized to addition of once-daily IDeg ('IDeg add-on to liraglutide' arm; n = 174) or placebo ('placebo add-on to liraglutide' arm; n = 172), with dosing of both IDeg and placebo based on titration guidelines.

RESULTS

At 26 weeks, the mean change in glycated haemoglobin level was greater in the IDeg add-on to liraglutide arm (-1.04%) than in the placebo add-on to liraglutide arm (-0.16%; p < 0.0001). Similarly, the mean fasting plasma glucose reduction was greater, and self-measured plasma glucose values were lower at all eight time points, with IDeg add-on versus placebo add-on (both p < 0.0001). At 26 weeks, the IDeg dose was 51 U (0.54 U/kg). During the run-in period with liraglutide, body weight decreased by ∼3 kg in both groups. After 26 weeks, the mean change was +2.0 kg (IDeg add-on to liraglutide) and -1.3 kg (placebo add-on to liraglutide). Confirmed hypoglycaemia rates were low in both groups, although higher with IDeg than with placebo (0.57 vs. 0.12 episodes/patient-years of exposure; p = 0.0002). Nocturnal confirmed hypoglycaemia was infrequent in both groups, with no episodes of severe hypoglycaemia, and no marked differences in adverse events with either treatment approach.

CONCLUSION

The addition of liraglutide and IDeg to patients sub-optimally treated with metformin and liraglutide and requiring treatment intensification was found to be effective and well-tolerated.

AMG 151 (ARRY-403), a novel glucokinase activator, decreases fasting and postprandial glycaemia in patients with type 2 diabetes

Phase I studies have shown that AMG 151 activates glucokinase, a key enzyme in glucose homeostasis. The present randomized, placebo-controlled phase IIa study evaluated the dose-effect relationship of the glucokinase activator AMG 151 relative to placebo on fasting plasma glucose (FPG) in 236 patients (33-35 patients per arm) with type 2 diabetes treated with metformin. Patients received oral AMG 151 at 50, 100 or 200 mg twice daily, AMG 151 at 100, 200 or 400 mg once daily or matching placebo for 28 days. A significant linear dose-effect trend was observed with the twice-daily regimen (p = 0.004) for change in FPG to day 28. No trend was observed with the once-daily regimen. A higher incidence of hypoglycaemia and hypertriglyceridaemia was observed with AMG 151 administration. AMG 151 significantly reduced FPG when administered twice daily but not when administered once daily in patients with type 2 diabetes treated with metformin.

Pulmonary function over 2 years in diabetic patients treated with prandial inhaled Technosphere Insulin or usual antidiabetes treatment: a randomized trial

AIMS

Development of inhaled insulin has increased the need to understand its pulmonary safety. This study evaluated pulmonary function changes in diabetes patients receiving inhaled Technosphere Insulin (TI) or usual antidiabetes treatment (usual care).

METHODS

This randomized, open-label study was conducted at 220 sites (25 July 2005 to 29 August 2008). Pulmonary function tests [forced expiratory volume in 1 s (FEV(1)), forced vital capacity (FVC), total lung capacity (TLC) and lung diffusion capacity for carbon monoxide (DL(CO))] were prospectively followed over 2 years in patients with type 1 or type 2 diabetes receiving TI (n = 730) or usual care (n = 824), along with a cohort without diabetes not receiving any specific therapy (n = 145).

RESULTS

Baseline demographics and pulmonary function were similar between diabetes treatment groups. Lung function declined from baseline in all groups. TI was non-inferior to usual care for mean change in FEV(1) from baseline to month 24 [mean (s.e.m.) 0.037 (0.0119) l; 95% CI 0.014 to 0.060] using mixed-model repeated-measure with a pre-specified non-inferiority margin of 50 ml/year. After a greater initial decline at month 3 with TI, rate of change (slope) in FEV(1), FVC and DL(CO) (months 3-24) was not statistically different between treatment groups. TI was well tolerated; no serious safety concerns emerged. The most common respiratory event associated with TI was mild, transient cough, occurring within minutes of inhalation.

CONCLUSIONS

Observed changes in lung function with TI were small, occurred early after therapy initiation, remained non-progressive over 2 years and were unlikely to be clinically meaningful.

Twice-daily and three-times-daily dosing of a repaglinide/metformin fixed-dose combination tablet provide similar glycaemic control

AIM

To assess the efficacy and safety of a new repaglinide/metformin fixed-dose combination (FDC) tablet administered either twice a day (BID) or three times a day (TID) for the management of type 2 diabetes.

METHODS

This was a 26-week, multicentre, open-label parallel trial in which subjects poorly controlled with mono- or dual-oral antidiabetic therapy were randomized 1 : 1 : 1 to instead receive repaglinide/metformin FDC either BID or TID or a rosiglitazone/metformin FDC BID. Two primary hypotheses were tested in a hierarchical manner: (i) treatment with the repaglinide/metformin FDC BID is non-inferior to that of the rosiglitazone/metformin FDC BID as measured by changes in haemoglobin A1c (HbA1c) (results presented in companion paper) and (ii) repaglinide/metformin BID is non-inferior to repaglinide/metformin TID (as measured by changes in HbA1c). Additional efficacy and safety end-points were also assessed.

RESULTS

A total of 561 subjects were randomized; 383 completed the study. Repaglinide/metformin FDC BID was non-inferior to repaglinide/metformin FDC TID with respect to HbA1c. Additionally, changes in mean fasting plasma glucose values from baseline to end of study were not significantly different between the BID and the TID dose groups. There were no major hypoglycaemic episodes reported in either group during the trial, and overall adverse event profiles were similar.

CONCLUSION

The efficacy of twice-daily dosing of a repaglinide/metformin FDC tablet was non-inferior to that of three-times-daily dosing.

Twice-daily dosing of a repaglinide/metformin fixed-dose combination tablet provides glycaemic control comparable to rosiglitazone/metformin tablet

AIM

To assess the use of a new repaglinide/metformin fixed-dose combination (FDC) tablet for the treatment of type 2 diabetes.

METHODS

In this 26-week, multicentre, open-label, parallel-group trial, subjects poorly controlled with mono- or dual-oral antidiabetic therapy were randomized 1 : 1 : 1 to receive a repaglinide/metformin FDC tablet either two times daily (BID) or three times daily (TID) or a rosiglitazone/metformin FDC tablet BID. The primary objective comprised two hypotheses tested in a hierarchical order: (i) that treatment with the repaglinide/metformin FDC BID is non-inferior to that of a rosiglitazone/metformin FDC tablet BID as measured by changes in haemoglobin A1c (HbA1c) (results presented here) and (ii) if true, that treatment with the repaglinide/metformin FDC BID was non-inferior to that of the repaglinide/metformin FDC TID as measured by changes in HbA1c (results presented in a companion paper). Additional efficacy and safety end-points were also assessed.

RESULTS

Of the 561 subjects randomized, 383 completed the study. Reductions in HbA1c values became apparent at earlier times for repaglinide/metformin FDC BID treatment than rosiglitazone/metformin FDC BID, and final changes in HbA1c were not significantly different between treatment arms (p = 0.8186); thus, the predefined statistical criterion for non-inferiority was met. Overall adverse event profiles were comparable between treatment groups, and no major hypoglycaemic episodes were reported during the study.

CONCLUSIONS

The repaglinide/metformin FDC BID regimen showed efficacy that was non-inferior to that of the rosiglitazone/metformin FDC BID regimen currently in clinical use and a more rapid reduction of HbA1c values. Thus, repaglinide/metformin FDC BID is a clinically feasible alternative to rosiglitazone/metformin FDC BID.

Patient-directed titration for achieving glycaemic goals using a once-daily basal insulin analogue: an assessment of two different fasting plasma glucose targets - the TITRATE study

AIMS

To compare efficacy and safety of two fasting plasma glucose (FPG) titration targets [4.4-6.1 mmol/l (80-110 mg/dl) and 3.9-5.0 mmol/l (70-90 mg/dl)] using a patient-directed, treat-to-target algorithm for once-daily basal insulin in insulin-naïve subjects with type 2 diabetes suboptimally treated with oral antidiabetes drugs (OADs).

METHODS

In this 20-week, randomized, controlled, open-label, multicentre, treat-to-target study, 244 insulin-naïve subjects with type 2 diabetes, HbA(1c)>or=7.0 and <or=9.0% on OAD treatment, were randomized (1 : 1) to one of two treatment arms using 3.9-5.0 or 4.4-6.1 mmol/l FPG as titration targets. Once-daily insulin detemir doses were adjusted using algorithm-guided patient-directed titration to achieve target FPG values.

RESULTS

Overall, the combined treatment groups achieved a mean HbA(1c) level of 6.9% at the end of the study. Substantial reductions in HbA(1c) were seen in both treatment groups, with the majority of subjects in both titration groups at the end of the study achieving the American Diabetes Association (ADA)-recommended HbA(1c) level of <7%. In the 3.9-5.0 mmol/l FPG target treatment group, HbA(1c) values decreased from a baseline mean of 8.0% to 6.8% at 20 weeks. In the 4.4-6.1 mmol/l FPG target group, HbA(1c) values decreased from 7.9% at baseline to 7.0% at 20 weeks (Intention to treat - last observation carried forward data set). These decreases were significantly different between the two treatment groups (Least squares mean difference = -0.271, 95% CI -0.441 to -0.101, p = 0.0019), favouring the FPG target of 3.9-5.0 mmol/l vs. the 4.4-6.1 mmol/l target. At the end of the study period, 64.3% of subjects in the 3.9-5.0 mmol/l treatment group achieved HbA(1c) levels <7% compared with 54.5% of subjects in the 4.4-6.1 mmol/l group (95% CI 1.03-3.37, odds ratio 1.86, p = 0.04). Insulin detemir dosing patterns were similar between treatment groups, with the 3.9-5.0 mmol/l group using slightly greater doses throughout the study period (0.57 U/kg vs. 0.51 U/kg at the end of the study). Overall rates of hypoglycaemia episodes were low and were comparable between treatment groups (7.73 and 5.27 events/subject/year for the 3.9-5.0 and 4.4-6.1 mmol/l groups, respectively). A single event of major hypoglycaemia was reported in the 3.9-5.0 mmol/l group. Mean weight changes from baseline to the end of the study were small and did not differ significantly between treatment groups.

CONCLUSIONS

The 3.9-5.0 mmol/l FPG target showed superior efficacy compared with the 4.4-6.1 mmol/l target, although both FPG titration targets resulted in substantial reductions of HbA(1c) in patients with type 2 diabetes using a patient-directed insulin titration algorithm. A majority of subjects in both titration groups achieved the ADA-recommended guideline of <7% HbA(1c) at the end of the study with low rates of hypoglycaemia. These data indicate that lowering the fasting glucose target using a self-directed titration algorithm with once-daily detemir is safe and increases the likelihood of achieving the target level of HbA(1c). Indeed, using this approach, a majority of patients can achieve an HbA(1c) of <7%.

Addition of biphasic insulin aspart 30 to optimized metformin and pioglitazone treatment of type 2 diabetes mellitus: The ACTION Study (Achieving Control Through Insulin plus Oral ageNts)

AIM

Efficacy and safety of biphasic insulin aspart (BIAsp 30, 30% short-acting and 70% intermediate-acting insulin aspart) added to an optimized treatment of metformin and pioglitazone (met/pio) were compared with treatment with optimized met/pio in type 2 diabetes patients.

METHODS

This randomized, 34-week, parallel-group study enrolled insulin-naive, type 2 diabetes patients (HbA(1c) 7.5-12.0%) previously using two oral antidiabetic (OAD) agents. During an 8-week run-in period, treatment was changed to met/pio and doses were adjusted up to 2500 mg/day and 30 or 45 mg/day respectively. Subjects either continued met/pio alone or added BIAsp 30 initiated at 6 units twice daily and titrated to target plasma glucose (PG) (4.4-6.1 mmol/l).

RESULTS

At end-of-study, subjects treated with BIAsp 30+met/pio (n = 93) had a mean (+/-s.d.) HbA(1c) reduction significantly greater than treatment with met/pio (n = 88) (1.5% +/- 1.1 vs. 0.2% +/- 0.9, p < 0.0001 between groups). Subjects treated with BIAsp 30+met/pio were more likely to reach The American Association of Clinical Endocrinologists and European Association for the Study of Diabetes/American Diabetes Association HbA(1c) targets of < or =6.5 and <7.0%, respectively, than with met/pio only (HbA(1c)< or =6.5%: 59 vs. 12%; HbA(1c) <7.0%: 76 vs. 24%). At end-of-study, self-monitored glucose profile values at all eight daily time points were significantly less for the BIAsp 30+met/pio group compared with the met/pio group, and minor hypoglycaemia (defined as PG < 3.1 mmol/l) was more frequent (8.3 vs. 0.1 events/year, p < 0.001). Both groups gained weight during treatment (BIAsp 30+met/pio, 4.6 +/- 4.3 kg; met/pio, 0.8 +/- 3.2 kg; p < 0.001).

CONCLUSION

Addition of insulin in type 2 patients treated with met/pio is an effective way to achieve glycaemic targets. Treatment with BIAsp 30+met/pio achieved significantly greater reduction in HbA(1c), as compared with met/pio alone. In patients with type 2 diabetes poorly controlled by 2 OADs, more achieved glycaemic targets using BIAsp 30+met/pio than using met/pio alone.

Oral combination therapy: repaglinide plus metformin for treatment of type 2 diabetes

Type 2 diabetes is characterized by decreases in insulin secretion and insulin sensitivity. Several classes of oral antidiabetic medications are currently approved for the treatment of type 2 diabetes. A stepwise treatment approach from monotherapy to combination therapy is traditionally used; however, the frequency of treatment failure with monotherapy has resulted in a move towards earlier treatment with combination therapies that target the two principal defects in glycaemic control. One such combination regimen is repaglinide (a prandial glucose regulator that increases insulin release) plus metformin (an insulin sensitizer that inhibits hepatic glucose output, increases peripheral glucose uptake and utilization and minimizes weight gain). Findings from several clinical trials have shown that combination therapy with repaglinide plus metformin is well tolerated and results in greater reductions of haemoglobin A(1c) and fasting plasma glucose values compared with either monotherapy. Repaglinide may also provide a more suitable alternative to combination therapy with sulphonylureas and metformin because of its reduced propensity for hypoglycaemia. The combination regimen of repaglinide plus metformin should therefore be considered as a valuable option in the management of patients with type 2 diabetes when monotherapy is no longer adequate.

Does serum 1,5-anhydroglucitol establish a relationship between improvements in HbA1c and postprandial glucose excursions? Supportive evidence utilizing the differential effects between biphasic insulin aspart 30 and insulin glargine

AIM

To investigate the relationship between changes in glycated haemoglobin (HbA(1c)) and postprandial glucose excursions on 1,5-anhydroglucitol (1,5-AG) in patients with Type 2 diabetes, utilizing the differential effects between biphasic insulin aspart 30 (BIAsp 30) or insulin glargine (IGlar) on postprandial glucose (PPG) levels.

METHODS

1,5-AG was measured using the GlycoMark assay at baseline and after 12 and 28 weeks in the INITiation of Insulin to reach HbA(1c) Target (INITIATE) study of 233 patients randomized to either BIAsp 30 or IGlar.

RESULTS

Baseline 1,5-AG was low and not significantly different (4.9 +/- 3.5 and 4.3 +/- 2.6 microg/ml in the BIAsp 30 and IGlar groups, respectively). After 28 weeks, the levels of 1,5-AG were higher in the BIAsp 30 than in the IGlar group (13.4 vs. 11.1 microg/ml, P = 0.008) and change from baseline was 25% greater with BIAsp 30 than IGlar (8.4 vs. 6.7 microg/ml, P = 0.011). 1,5-AG levels increased as a function of decreasing HbA(1c) or the average change in postprandial plasma glucose (PPG(ave)) with significant relationships for 1,5-AG/ HbA(1c) vs. HbA(1c) or 1,5-AG/PPG(ave )vs. PPG(ave) (both P < 0.0001), respectively.

CONCLUSIONS

As reported in previous publications, 1,5-AG reflects ambient glycaemic control and increases with reductions in HbA(1c) and postprandial glucose. The greater reductions in postprandial excursion achieved with BiAsp 30 compared with glargine were associated with greater increases in 1,5-AG. Even moderate elevations in HbA(1c) substantially lower 1,5-AG, suggesting that it can be most discriminating in identifying patients with excessive postprandial glucose excursions at HbA(1c) levels that approach the upper end of the normal range.

Differential effect of beta-blocker therapy on insulin resistance as a function of insulin sensitizer use: results from GEMINI

AIMS

To determine whether the beneficial effects of carvedilol on insulin resistance (IR) are affected by the concomitant use of insulin sensitizers [thiazolidinediones (TZDs) and metformin].

METHODS

Changes in HbA1c and homeostasis model assessment-insulin resistance (HOMA-IR) were assessed over 5 months, comparing carvedilol with metoprolol tartrate according to insulin sensitizer (TZDs and metformin) use.

RESULTS

In TZD/metformin users, carvedilol patients showed a 5.4% decrease [95% confidence interval (CI) -11.9, 1.6; P = 0.13] and metoprolol tartrate patients showed a 2.8% decrease (95% CI -8.5, 3.2; P = 0.35) in HOMA-IR. The -2.6% difference between treatments was not significant (95% CI -10.7, 6.2; P = 0.55). In contrast, those not taking TZD/metformin experienced a 13.2% increase in HOMA-IR on metoprolol tartrate (95% CI 3.2, 24.1; P < 0.01) and a 4.8% decrease in HOMA-IR on carvedilol (95% CI -14.6, 6.0; P = 0.37), with a significant treatment difference of -15.9% favouring carvedilol (95% CI -26.6, -3.6; P = 0.01). There was no significant treatment interaction for the use of TZD/metformin and HbA1c. A statistically significant treatment difference was observed for HbA1c after 5 months favouring carvedilol after adjusting for insulin sensitizer use (-0.11%, 95% CI -0.214, -0.009; P = 0.03).

CONCLUSIONS

In patients with diabetes and hypertension not taking insulin sensitizers, the use of metoprolol tartrate resulted in a worsening of insulin resistance, an effect not seen with carvedilol. However, in TZD/metformin users the difference between the beta-blockers was not statistically significant.

beta-blocker use and diabetes symptom score: results from the GEMINI study

AIM

The Glycemic Effect in Diabetes Mellitus: Carvedilol-Metoprolol Comparison in Hypertensives (GEMINI) trial compared the metabolic effects of two beta-blockers in people with type 2 diabetes and hypertension treated with renin-angiotensin system (RAS) blockade and found differences in metabolic outcomes. In this paper, we report the results of a prespecified secondary analysis of GEMINI that sought to determine the effect of these two beta-blockers on commonly reported symptoms.

METHODS

The Diabetes Symptom Checklist (DSC), a self-report questionnaire measuring the occurrence and perceived burden of diabetes-related symptoms, was completed by GEMINI participants at baseline and at the end of the study (maintenance month 5). The DSC assessed symptoms in eight domains: psychology (fatigue), psychology (cognitive), neuropathy (pain), neuropathy (sensory), cardiology, ophthalmology, hyperglycaemia and hypoglycaemia.

RESULTS

Comparison of the mean change in self-reported diabetes-related symptoms indicated a significant treatment difference favouring carvedilol over metoprolol tartrate in overall symptom score (-0.08; 95% CI -0.15, -0.01; p = 0.02) and in the domains for hypoglycaemia symptoms (-0.12; 95% CI -0.23, -0.02; p = 0.02) and hyperglycaemia symptoms (-0.16; 95% CI -0.27, -0.05; p = 0.005). Carvedilol resulted in fewer perceived diabetes-related symptoms in patients with diabetes and hypertension.

CONCLUSION

Carvedilol resulted in a lower perceived burden of diabetes-related symptoms in patients with type 2 diabetes and hypertension. The addition of a well-tolerated beta-blocker to RAS blockade may improve hypertension treatment and quality of life in patients with diabetes.

Weight gain in type 2 diabetes mellitus

OBJECTIVE

To investigate the potential causes of weight gain using insulin and combination therapy in type 2 diabetes.

DESIGN AND METHODS

This was an open-label prospective study of 6-month duration. Randomization was performed to insulin monotherapy, insulin and pioglitazone 30 mg daily, or insulin and metformin up to 2000 mg daily. Fifty-seven subjects with poorly controlled type 2 diabetes were enrolled. The goal was to achieve a normal haemoglobin A1c (HbA1c) (<5.6%). Weight, resting energy expenditure (REE), reported energy intake and total energy expenditure, HbA1c, glycosuria, plasma leptin, ghrelin and adiponectin levels, and body fat were measured.

RESULTS

A total of 49 subjects completed the study. At baseline, weight was 89.4 +/- 22.9 kg and HbA1c was 11.1 +/- 1.5%. Weight increased by 7.46, 7.60 and 7.12 kg in the monotherapy, metformin and pioglitazone groups, respectively [p = 0.98 between and <0.0001 within the groups by repeated measures-analysis of variance (RM-anova)]. HbA1c dropped to 7.8 +/- 0.9% in the monotherapy arm, 7.6 +/- 1.0% in the metformin arm and 7.2 +/- 1.2% in the pioglitazone arm. Reported energy intake decreased. Glycosuria decreased but was not correlated with weight gain, while HbA1c changes were correlated with weight gain. REE per lean mass decreased (p = 0.04 by RM-anova). The subcutaneous fat areas in the insulin monotherapy and pioglitazone arms showed increases (p = 0.02 and 0.004 respectively).

CONCLUSIONS

Weight gain was probably not due to an increase in food intake, while REE per lean body mass decreased, suggesting a role for increased efficiency in fuel usage due to improved glycaemic control. A drop in glycosuria probably also contributed to weight gain. In the monotherapy and pioglitazone arms, the subcutaneous fat areas increased.

Insulin therapy in type 2 diabetes patients failing oral agents: cost-effectiveness of biphasic insulin aspart 70/30 vs. insulin glargine in the US

OBJECTIVES

To project the long-term clinical and economic outcomes of treatment with biphasic insulin aspart 30 (BIAsp 70/30, 30% soluble and 70% protaminated insulin aspart) vs. insulin glargine in insulin-naïve type 2 diabetes patients failing to achieve glycemic control with oral antidiabetic agents alone (OADs).

METHODS

Baseline patient characteristics and treatment effect data from the recent 'INITIATE' clinical trial served as input to a peer-reviewed, validated Markov/Monte-Carlo simulation model. INITIATE demonstrated improvements in HbA1c favouring BIAsp 70/30 vs. glargine (-0.43%; p < 0.005) and greater efficacy in reaching glycaemic targets among patients poorly controlled on OAD therapy. Effects on life expectancy (LE), quality-adjusted life expectancy (QALE), cumulative incidence of diabetes-related complications and direct medical costs (2004 USD) were projected over 35 years. Clinical outcomes and costs were discounted at a rate of 3.0% per annum. Sensitivity analyses were performed.

RESULTS

Improvements in glycaemic control were projected to lead to gains in LE (0.19 +/- 0.24 years) and QALE (0.19 +/- 0.17 years) favouring BIAsp 70/30 vs. glargine. Treatment with BIAsp 70/30 was also associated with reductions in the cumulative incidences of diabetes-related complications, notably in renal and retinal conditions. The incremental cost-effectiveness ratio was $46 533 per quality-adjusted life year gained with BIAsp 70/30 vs. glargine (for patients with baseline HbA1c >/= 8.5%, it was $34 916). Total lifetime costs were compared to efficacy rates in both arms as a ratio, which revealed that the lifetime cost per patient treated successfully to target HbA1c levels of <7.0% and </= 6.5% were $80 523 and $93 242 lower with BIAsp 70/30 than with glargine, respectively.

CONCLUSIONS

Long-term treatment with BIAsp 70/30 was projected to be cost-effective for patients with type 2 diabetes insufficiently controlled on OADs alone compared to glargine. Treatment with BIAsp 70/30 was estimated to represent an appropriate investment of healthcare dollars in the management of type 2 diabetes.

The visceral and subcutaneous fat changes in type 1 diabetes: a pilot study

OBJECTIVE

To evaluate the effects of improved glycaemic control on the abdominal visceral and subcutaneous fat in type 1 diabetes.

RESEARCH DESIGN AND METHODS

Sixteen subjects were enrolled for this 6-month study. The goal was to achieve normal haemoglobin A1c (HbA1c <5.6% in our laboratory). T1-weighted magnetic resonance imaging was used to measure the abdominal subcutaneous and visceral fat areas at the L2-L3 disk level. Activity and energy intake were assessed using a weekly recall and food diary respectively. Plasma leptin, ghrelin and adiponectin levels were measured at baseline and at 6 months.

RESULTS

Twelve subjects completed the study. HbA1c was 10.4 +/- 2.2% at baseline, and abdominal visceral to subcutaneous fat ratio was 0.29 +/- 0.15. HbA1c dropped to 8.0 +/- 1.4% at 6 months (p = 0.009). There was a +1.85 kg weight change in 6 months (p = 0.30), whereas the visceral to subcutaneous fat ratios changed to 0.36 +/- 0.18 (p = 0.22). Daily metabolic equivalents (METs) of activity at 6 months correlated with a decrease in the visceral to subcutaneous fat ratios (r = -0.80, p = 0.01). Ghrelin level changes correlated negatively with the changes in the visceral to subcutaneous fat ratio (p < 0.01).

CONCLUSIONS

The visceral to subcutaneous fat changes had a negative correlation with the physical activity METs at 6 months but not with HbA1c changes in this study. The correlation between the changes in ghrelin and the visceral to subcutaneous fat ratios is intriguing, but a larger study may be needed to confirm this finding.

Potential causes of weight gain in type 1 diabetes mellitus

AIM

To investigate the potential causes of weight gain with insulin therapy and improved diabetic control in type 1 diabetes mellitus.

METHODS

This was an open-label prospective study of insulin therapy of 6 months duration in an academic medical centre. Twenty-one subjects with type 1 diabetes were enrolled. The goal was to achieve an haemoglobin A1c (HbA1c) in the range of individuals without diabetes (<5.6%). At baseline, 3 and 6 months, weight, resting energy expenditure, appetite assessment, food intake, activity level, HbA1c and 24-h glycosuria and urea nitrogen were measured. Plasma leptin, ghrelin and adiponectin levels and body fat were measured at baseline and 6 months.

RESULTS

At baseline, average weight was 73.7 +/- 17.4 kg and HbA1c was 10.0 +/- 2.2%. Weight increased by 2.15 kg (2.69% of baseline) by 6 months whereas the HbA1c dropped by 1.71% (16.3%) to 7.9%. Energy intake differences between 3 and 6 months had a negative correlation with weight gain, but the changes in glycosuria, appetite scores and the frequency of hypoglycaemia did not correlate with weight gain. Glycaemic control did not correlate with weight change but tended to correlate with fat mass increase (p = 0.064; r = -0.51). An increase in the activity levels between 3 and 6 months correlated with decreasing fat mass (p = 0.037; r = -0.74). The changes in the appetite scores had a negative correlation with fat mass gain (p = 0.035; r = -0.61). The changes in lean body mass correlated with protein and total energy intake (p = 0.007, r = 0.85 and p = 0.003, r = 0.73 respectively). The changes in leptin levels correlated with weight gain.

CONCLUSIONS

The lipogenic effect of insulin with subsequent increase in fat mass may be the primary cause of this weight gain that can be attenuated by the increases in the activity levels. The negative correlation of energy intake and appetite scores with fat mass gain suggests that they do not play a significant role in fat mass gain whereas energy intake did correlate with lean body mass gain.

Topiramate vs placebo in painful diabetic neuropathy: analgesic and metabolic effects

BACKGROUND

Using identical methods, three simultaneous placebo-controlled trials of topiramate for painful diabetic neuropathy (PDN) did not reach significance. This independent yet concurrent placebo-controlled trial used different methods to assess topiramate efficacy and tolerability in PDN.

METHODS

This 12-week, multicenter, randomized, double-blind trial included 323 subjects with PDN and pain visual analog (PVA) score of at least 40 on a scale from 0 (no pain) to 100 (worst possible pain). Topiramate (n = 214) or placebo (n = 109) was titrated to 400 mg daily or maximum tolerated dose. Short-acting rescue analgesics were permitted only during the first 6 weeks.

RESULTS

Baseline characteristics were comparable between groups except for mean body weight (topiramate, 101.4 kg; placebo, 95.7 kg; p = 0.028). Twelve weeks of topiramate treatment reduced PVA scale score (from 68.0 to 46.2 mm) more effectively than placebo (from 69.1 to 54.0 mm; p = 0.038). Fifty percent of topiramate-treated subjects and 34% of placebo-treated subjects responded to treatment, defined as >30% reduction in PVA scale score (p = 0.004). Topiramate monotherapy also reduced worst pain intensity (p = 0.003 vs placebo) and sleep disruption (p = 0.020 vs placebo). Diarrhea, loss of appetite, and somnolence were the most commonly reported adverse events in the topiramate group. Topiramate reduced body weight (-2.6 vs +0.2 kg for placebo; p < 0.001) without disrupting glycemic control.

CONCLUSIONS

Topiramate monotherapy reduced pain and body weight more effectively than placebo in patients with painful diabetic neuropathy.

Combination therapy for type 2 diabetes: repaglinide plus rosiglitazone

AIMS

This 24-week, randomized, multicentre, open-label, parallel-group clinical trial compared efficacy and safety of repaglinide monotherapy, rosiglitazone monotherapy, and combination therapy (repaglinide plus rosiglitazone) in Type 2 diabetes after unsatisfactory response to sulphonylurea or metformin monotherapy.

METHODS

Enrolled patients (n = 252) were adults having Type 2 diabetes for at least 1 year, with HbA(1c) values > 7.0% after previous monotherapy (sulphonylurea or metformin, >/= 50% maximal dose). Prior therapy was withdrawn for 2 weeks, followed by randomization to repaglinide, rosiglitazone, or repaglinide/rosiglitazone. Study treatments were initiated with a 12-week dose optimization period (doses optimized according to labelling), followed by a 12-week maintenance period. Efficacy endpoints were changes in HbA(1c) values (primary) or fasting plasma glucose values (secondary).

RESULTS

Baseline HbA(1c) values were comparable (9.3% for repaglinide, 9.0% for rosiglitazone, 9.1% for combination). Mean changes in HbA(1c) values at the end of treatment were greater for repaglinide/rosiglitazone therapy (-1.43%) than for repaglinide (-0.17%) or rosiglitazone (-0.56%) monotherapy. Reductions of fasting plasma glucose values were also greater for combination therapy (-5.2 mmol/l, -94 mg/dl) than for repaglinide monotherapy (-3.0 mmol/l, -54 mg/dl) or rosiglitazone monotherapy (-3.7 mmol/l, -67 mg/dl). Minor hypoglycaemic events occurred in 9% of combination therapy patients, vs. 6% for repaglinide and 2% for rosiglitazone. Individual weight gains for combination therapy were correlated to HbA(1c) response.

CONCLUSIONS

The combination therapy regimen was well tolerated. In patients previously showing unsatisfactory response to oral monotherapy, glycaemic reductions were greater for the repaglinide/rosiglitazone combination regimen than for use of either repaglinide or rosiglitazone alone.

A comparison of insulin lispro and buffered regular human insulin administered via continuous subcutaneous insulin infusion pump

This study compared glycemic control achieved with insulin lispro or buffered regular human insulin in patients with Type 1 diabetes treated with continuous subcutaneous insulin infusion (CSII) using an external insulin pump. In this 24-week multicenter, randomized, two-way crossover, open-label trial, 58 patients on CSII with adequate glycemic control received either insulin lispro or buffered regular human insulin for 12 weeks, followed by the alternate treatment for another 12 weeks. Efficacy and safety measures included hemoglobin A(1c) (HbA(1c)) at baseline and endpoint, home blood glucose monitoring, hypoglycemia, and frequency of pump catheter occlusion. Patients consumed a standard test meal on three occasions, with determinations of fasting, 1- and 2-h postprandial glucose values. Insulin lispro use was associated with a significantly lower HbA(1c) than was buffered regular human insulin (7.41+/-0.97 vs. 7.65+/-0.85 mmol/l; P=.004). Fasting serum glucose values before the test meal were similar between the two therapies. The 1-h (11.16+/-4.29 vs. 13.20+/-4.68 mmol/l; P=.012) and 2-h (9.64+/-4.10 vs. 12.53+/-4.64 mmol/l; P=.001) postprandial glucose concentrations were significantly lower during treatment with insulin lispro. No differences between treatments were observed in basal or bolus insulin doses, weight gain, or the incidence and rate of hypoglycemia, hyperglycemia, or pump occlusions. When used in external pumps, insulin lispro provides better glycemic control than buffered regular human insulin with a similar adverse event profile.

Idiopathic Type 1 diabetes

The purpose of this article is to review the available pathophysiological and clinical studies of patients with idiopathic Type 1 diabetes. Idiopathic Type 1 diabetes is a common form of diabetes most commonly seen in obese African American individuals living in large urban areas. This type of diabetes usually presents with the typical signs and symptoms of Type 1 diabetes such as diabetic ketoacidosis but its subsequent clinical course often resembles Type 2 diabetes. The natural history and pathogenesis of idiopathic Type 1 diabetes is unknown because most of these studies on these patients were done shortly after diagnosis. For the most part, these patients have been treated as if they had Type 2 diabetes with diet and/or oral agents but recent studies suggest that patients have a very variable response to diet and oral agents. They seem to have better long-term glycemic control with the use of insulin therapy. Although the pathogenesis of this disease is unknown, it may be related to lipotoxicity, glucose toxicity or transcription factors involved in fuel metabolism.

A randomized trial of rosiglitazone therapy in patients with inadequately controlled insulin-treated type 2 diabetes

OBJECTIVE

To determine the efficacy and safety of rosiglitazone (RSG) when added to insulin in the treatment of type 2 diabetic patients who are inadequately controlled on insulin monotherapy.

RESEARCH DESIGN AND METHODS

After 8 weeks of insulin standardization and placebo (PBO) run-in, 319 type 2 diabetic patients with mean baseline HbA(1c) > or = 7.5% (8.9 +/- 1.1 to 9.1 +/- 1.3) on twice-daily insulin therapy (total daily dose > or = 30 U) were randomized to 26 weeks of additional treatment with RSG (4 or 8 mg daily) or PBO. Insulin dose could be down- titrated only for safety reasons. The primary end point was reduction of HbA(1c) from baseline.

RESULTS

RSG 4 and 8 mg daily significantly improved glycemic control, which was unchanged on PBO. By intent-to-treat analysis, treatment with RSG 8 mg plus insulin resulted in a mean reduction from baseline in HbA(1c) of 1.2% (P < 0.0001), despite a 12% mean reduction of insulin dosage. Over 50% of subjects treated daily with RSG 8 mg plus insulin had a reduction of HbA(1c) > or = 1.0%. Neither total:HDL cholesterol nor LDL:HDL cholesterol ratios significantly changed with RSG treatment. Serious adverse events did not differ among groups.

CONCLUSIONS

The addition of RSG to insulin treatment results in significant improvement in glycemic control and is generally well tolerated.

Idiopathic type 1 diabetes in Dallas, Texas: a 5-year experience

OBJECTIVE

To describe the clinical course of individuals with idiopathic type 1 diabetes after a mean of 5 years from diagnosis and to compare glycemic control between those treated with diet and/or oral agents and those treated with insulin at follow-up.

RESEARCH DESIGN AND METHODS

Medical records of patients with new-onset diabetes, who presented with unprovoked diabetic ketoacidosis, were reviewed. A total of 54 of these individuals were traceable and had relevant data collected within the past 2 years. All patients had nonsusceptibility HLA haplotypes and no serological evidence of autoimmune type 1 diabetes. Most of these patients were male (41 men and 13 women), were non-Caucasian, were obese at the time of diagnosis (BMI 31.6 +/- 6.3 kg/m(2)), reported weight loss (12.8 +/- 9.8 kg), had a family history of type 2 diabetes, and had acanthosis nigricans. At follow-up, 33 patients were still taking insulin and 21 were on diet and/or oral-agent therapy.

RESULTS

Both treatment groups were similar in clinical presentation and demographics at diagnosis. After 4.8 +/- 1.6 years of follow-up, the 33 patients that were receiving insulin had a lower HbA(1c) than the 21 patients who were using therapies other than insulin (7.8 +/- 2.4 vs. 11.1 +/- 3.5%, P = 0.009; 95% CI 1.0-6.5%). There was a high correlation between change in weight and change in HbA(1c) at follow-up (r = 0.45, P < 0.001, n = 54). There were no differences in the rate of diabetes complications or in the episodes of recurrent diabetic ketoacidosis.

CONCLUSIONS

Idiopathic type 1 diabetes occurs more frequently in male African-American patients but also occurs in other ethnic groups. Patients with idiopathic type 1 diabetes who continued to use insulin had better glycemic control than patients using therapies other than insulin. Regained weight is a good clinical marker for improvement in glycemic control. Individuals with this type of diabetes should not be switched to therapies other than insulin.

Familial factors in the antihypertensive response to lisinopril

BACKGROUND

Although it is widely recognized that there are familial elements in the pathogenesis of hypertension, remarkably little is known about the influence of family history on response to specific antihypertensive agents.

METHODS

This study was designed to address that issue by comparing the depressor response to lisinopril in a dose range of 10 to 40 mg in 74 patients enrolled as sibling pairs. Because all patients were treated with lisinopril, ambulatory blood pressure monitoring (ABPM), an objective measure not influenced by the investigators, was used to assess the primary blood pressure (BP) outcome variable.

RESULTS

Diastolic BP was highly correlated between sibling pairs at baseline (r = 0.476; P < .03) and on treatment (r = 0.524; P = .0021). Ethnicity/race had a striking influence on lisinopril dose and response rate. Among African American patients, 23 of 28 reached the top dose of 40 mg/day, whereas only 14 of 36 Caucasian patients reached that dose level. Among Caucasians, 92% responded, and only 48% of African Americans. Responders were characterized by being younger and heavier, having significantly lower microalbuminuria at baseline, higher baseline renal plasma flow (RPF), and higher urinary kallikrein.

CONCLUSION

Among Caucasians, the presence of a hypertensive sibling predicts a striking therapeutic response to angiotensin converting enzyme inhibition.

A 16-week comparison of the novel insulin analog insulin glargine (HOE 901) and NPH human insulin used with insulin lispro in patients with type 1 diabetes

OBJECTIVE

To determine the safety and efficacy of the long-acting insulin analog, insulin glargine, as a component of basal bolus therapy in patients with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Patients with type 1 diabetes receiving basal-bolus insulin treatment with NPH human insulin and insulin lispro were randomized to receive insulin glargine (HOE 901), a long-acting basal insulin analog, once a day (n = 310) or NPH human insulin (n = 309) as basal treatment with continued bolus insulin lispro for 16 weeks in an open-label study NPH insulin patients maintained their prior schedule of administration once or twice a day, whereas insulin glargine patients received basal insulin once a day at bedtime.

RESULTS

Compared with all NPH insulin patients, insulin glargine patients had significant decreases in fasting blood glucose measured at home (means +/- SEM, -42.0 +/- 4.7 vs. -12.4 +/- 4.7 mg/dl [-2.33 +/- 0.26 vs. -0.69 +/- 0.26 mmol/l]; P = 0.0001). These differences were evident early and persisted throughout the study More patients in the insulin glargine group (29.6%) than in the NPH group (16.8%) reached a target fasting blood glucose of 119 mg/dl (< 6.6 mmol/l). However, there were no differences between the groups with respect to change in GHb. Insulin glargine treatment was also associated with a significant decrease in the variability of fasting blood glucose values (P = 0.0124). No differences in the occurrence of symptomatic hypoglycemia, including nocturnal hypoglycemia, were observed. Overall, adverse events were similar in the two treatment groups with the exception of injection site pain, which was more common in the insulin glargine group (6.1%) than in the NPH group (0.3%). Weight gain was 0.12 kg in insulin glargine patients and 0.54 kg in NPH insulin patients (P = 0.034).

CONCLUSIONS

Basal insulin therapy with insulin glargine once a day appears to be as safe and at least as effective as using NPH insulin once or twice a day in maintaining glycemic control in patients with type 1 diabetes receiving basal-bolus insulin treatment with insulin lispro.

Repaglinide/troglitazone combination therapy: improved glycemic control in type 2 diabetes

OBJECTIVE

This multicenter open-label clinical trial compared the efficacy and safety of repaglinide/troglitazone combination therapy, repaglinide monotherapy, and troglitazone monotherapy in type 2 diabetes that had been inadequately controlled by sulfonylureas, acarbose, or metformin alone.

RESEARCH DESIGN AND METHODS

Patients with type 2 diabetes (n = 256) who had inadequate glycemic control (HbA1c > or =7.0%) during previous monotherapy were randomly assigned to receive repaglinide (0.5-4.0 mg at meals), troglitazone (200-600 mg once daily), or a combination of repaglinide (1-4 mg at meals) and troglitazone (200-600 mg once daily). After a 4-6 week washout period, the trial assessed 22 weeks of treatment: 3 weeks (weeks 0-2) of forced titration, 11 weeks of fixed-dose treatment (weeks 3-13), and 8 weeks (weeks 14-21) of titration to maximum dose. Changes in HbA1c and fasting plasma glucose (FPG) values were measured.

RESULTS

The combination therapy showed a significant reduction in mean HbA1c values (-1.7%) that was greater than with either type of monotherapy Repaglinide monotherapy resulted in a reduction of HbA1c values that was significantly greater than troglitazone (-0.8 vs. -0.4%) (P < 0.05). Combination therapy was more effective in reducing FPG values (-80 mg/dl) than either repaglinide (-43 mg/dl) or troglitazone (-46 mg/dl) monotherapies. Adverse events were similar in all groups.

CONCLUSIONS

Combination therapy with repaglinide and troglitazone leads to better glycemic control than monotherapy with either agent alone. Repaglinide monotherapy was more effective in lowering HbA1c levels than troglitazone monotherapy Repaglinide/troglitazone combination therapy was effective and did not show unexpected adverse events.

Weight loss with sibutramine improves glycaemic control and other metabolic parameters in obese patients with type 2 diabetes mellitus

AIM

To determine the efficacy and tolerability of sibutramine hydrochloride in obese patients whose type 2 diabetes was poorly controlled on diet alone or with an oral antidiabetic agent.

METHODS

This study was a 24-week, double-blind, multicentre trial following a 5-week placebo run-in period. One hundred and seventy-five obese (body mass index (b.m.i.) > or =27 kg/m2) patients with poorly controlled type 2 diabetes mellitus were randomized either to sibutramine (n = 89; mean age 53.5 years; mean weight 99.3 kg) or placebo (n = 86; mean age 55 years; mean weight 98.2 kg) at 16 participating centres. To achieve moderate calorie restriction (deficit > or = 250-500 kcal/day), individual dietary counselling was accompanied by either placebo or sibutramine (initial dosage of 5 mg/day titrated up by 5 mg biweekly through week 6, and maintained at 20 mg through week 24). The main outcome measures included changes in weight, b.m.i., waist and hip circumference, glycaemic control, lipid profile, and quality of life, and evaluation of reported adverse events.

RESULTS

Sixty-seven per cent of sibutramine patients and 71% of placebo patients completed the study. At week 24 when comparing those who completed the course, sibutramine compared with placebo patients showed significantly greater (p < 0.001) absolute (-4.3 vs. -0.4 kg) and percentage (-4.5% vs. -0.5%) weight loss. Weight loss > or =5% or 10% was achieved by 33% and 8% of sibutramine patients, respectively, but no placebo patients (p < 0.03 or better). Improvement in glycaemic control was correlated with weight loss (p < 0.001). In 5% and 10% weight-loss responders, mean treatment differences were -0.53% and -1.65% (p < or = 0.05), respectively, for HbA1c, and -1.4 mmol/l (p < or =0.05) and -3.8 (p < or =0.05) mmol/l for fasting plasma glucose. Sibutramine patients also showed improvements in fasting insulin, triglycerides, HDL cholesterol, and quality-of-life assessments. Overall, sibutramine was well tolerated compared with the placebo. Sibutramine treatment was associated with small mean increases in blood pressure (BP) and pulse, although an increase in BP was not seen in sibutramine-treated patients who lost > or = 5% of their weight.

CONCLUSIONS

Sibutramine produced statistically and clinically significant weight loss when used in combination with recommendations for moderate caloric restriction. This weight loss was associated with improvements in metabolic control and quality of life, and sibutramine was generally well tolerated in obese patients with type 2 diabetes.

Use of insulin aspart, a fast-acting insulin analog, as the mealtime insulin in the management of patients with type 1 diabetes

OBJECTIVE

To compare long-term glycemic control and safety of using insulin aspart (IAsp) with that of regular human insulin (HI).

RESEARCH DESIGN AND METHODS

This was a multicenter randomized open-label 6-month study (882 subjects) with a 6-month extension period (714 subjects) that enrolled subjects with type 1 diabetes. Subjects administered IAsp immediately before meals or regular HI 30 min before meals; basal NPH insulin was taken as a single bedtime dose in the majority of subjects. Glycemic control was assessed with HbA1c values and 8-point blood glucose profiles at 3-month intervals.

RESULTS

Mean postprandial blood glucose levels (mg/dl +/- SEM) were significantly lower for subjects in the IAsp group compared with subjects in the HI group after breakfast (156 +/- 3.4 vs. 185 +/- 4.7), lunch (137 +/- 3.1 vs. 162 +/- 4.1), and dinner (153 +/- 3.1 vs. 168 +/- 4.1), when assessed after 6 months of treatment. Mean HbA1c values (% +/- SEM) were slightly, but significantly, lower for the IAsp group (7.78% +/- 0.03) than for the regular HI group (7.93% +/- 0.05, P = 0.005) at 6 months. Similar postprandial blood glucose and HbA1c values were observed at 12 months. Adverse events and overall hypoglycemic episodes were similar for both treatment groups.

CONCLUSIONS

Postprandial glycemic control was significantly better with IAsp compared with HI after 6 and 12 months of treatment. The improvement was not obtained at an increased risk of hypoglycemia. HbA1c was slightly, but significantly, lower for IAsp compared with HI at 6 and 12 months.

Maintenance of the long-term effectiveness of tramadol in treatment of the pain of diabetic neuropathy

OBJECTIVE

The objective of this study was to evaluate the efficacy and safety of tramadol in a 6-month open extension following a 6-week double-blind randomized trial.

RESEARCH DESIGN AND METHODS

Patients with painful diabetic neuropathy who completed the double-blind study were eligible for enrollment in an open extension of up to 6 months. All patients received tramadol 50-400 mg/day. Self-administered pain intensity scores (scale 0-4; none to extreme pain) and pain relief scores (scale -1-4; worse to complete relief) were recorded the first day of the open extension (last day of the double-blind phase) and at 30, 90, and 180 days.

RESULTS

A total of 117 patients (56 former tramadol and 61 former placebo) entered the study. On the first day of the study, patients formerly treated with placebo had a significantly higher mean pain intensity score (2. 2+/-1.02 vs. 1.4+/-0.93, P<0.001) and a lower pain relief score (0. 9+/-1.43 vs. 2.2+/-1.27, P<0.001) than former tramadol patients. By Day 90, both groups had mean pain intensity scores of 1.4, which were maintained throughout the study. Mean pain relief scores (2. 4+/-1.09 vs. 2.2+/-1.14) were similar after 30 days in the former placebo and former tramadol groups, respectively and were maintained for the duration of the study. Four patients discontinued therapy due to ineffective pain relief; 13 patients discontinued due to adverse events. The most common adverse events were constipation, nausea, and headache.

CONCLUSIONS

Tramadol provides long-term relief of the pain of diabetic neuropathy.

Cardiovascular risk in diabetes: a brief review

Cardiovascular disease (CVD) is the major cause of the morbidity and mortality associated with diabetes in the US. A 2- to 3-fold incidence of CVD occurs in both type 1 and type 2 diabetic individuals over that in age- and gender-matched non-diabetic persons. Recent encouraging data demonstrating a decline in CVD mortality in the general US population do not reflect such a decline in the diabetic population, particularly in women. Increased risk for CVD is related to duration of diabetes and hyperglycemia, as well as hypertension, dyslipidemia, insulin resistance, gender, coagulation abnormalities, and other factors. Health care providers need to advocate for an uncompromising, multi-component attack on all modifiable risk factors for CVD, including glucose control, in the person with diabetes mellitus. This review focuses on known modifiable risk factors for CVD associated with diabetes, potential targets for primary and secondary prevention.

Rosiglitazone short-term monotherapy lowers fasting and post-prandial glucose in patients with type II diabetes

AIMS/HYPOTHESIS

The short-term efficacy, safety and tolerability of rosiglitazone were compared with placebo in patients with Type II (non-insulin-dependent) diabetes mellitus in a dose-ranging study.

METHODS

After a 2-week placebo run-in phase, 303 patients were randomly assigned to 8 weeks of treatment with twice-daily placebo or 2, 4 or 6 mg of rosiglitazone.

RESULTS

All rosiglitazone doses significantly reduced fasting plasma glucose compared with baseline. All rosiglitazone treatment groups showed significantly reduced peak postprandial glucose concentrations compared with baseline (p < 0.001) and with placebo (p < 0.0001) and reduced postprandial glucose excursion, without an increase in the area under the postprandial insulin concentration-time curve. Rosiglitazone at 4 and 6 mg twice daily prevented the increase in HbA1c observed in the placebo group. C peptide and serum insulin concentrations were significantly reduced from baseline in all rosiglitazone treatment groups. In all rosiglitazone treatment groups, nonesterified fatty acids decreased significantly (p < 0.0001) and triglycerides did not change. Although total LDL and HDL cholesterol increased significantly in the rosiglitazone treatment groups, total cholesterol/HDL ratios did not change significantly. The proportion of patients with one or more adverse event was similar in all four treatment groups. No patient showed evidence of hepatotoxicity.

CONCLUSION/INTERPRETATION

Rosiglitazone given twice daily significantly reduced fasting and postprandial glucose concentrations, C peptide, insulin and nonesterified fatty acids in Type II diabetic patients. The glucose-lowering effect of the 4-mg twice-daily dose of rosiglitazone was similar to that of 6-mg twice daily, suggesting that 4 mg twice daily should be the maximum clinical dose.

The long-term antihypertensive activity and tolerability of irbesartan with hydrochlorothiazide

The long-term safety, tolerability, and antihypertensive effects of irbesartan/hydrochlorothiazide (HCTZ) were assessed in hypertensive patients (seated diastolic blood pressure [SeDBP] 95-110 mm Hg). Patients (n = 1098) completing two randomised, double-blind trials of irbesartan alone, HCTZ alone, irbesartan/HCTZ combinations, or placebo, took 1 year of open-label therapy starting with irbesartan 75 mg/HCTZ 12.5 mg once daily. If target blood pressure (BP) (<140/<90 mm Hg) was not achieved, the dose was titrated sequentially at 2- to 4-week intervals to irbesartan 150 mg/HCTZ 12. 5 mg, then to irbesartan 300 mg/HCTZ 25 mg. If necessary, adjunctive therapies were added. Mean changes in trough seated systolic BP/SeDBP at months 2, 6, and 12 were -19.1/-14.2 mm Hg (n = 941), -20.7/ -15.7 mm Hg (n = 948), and -20.6/-15.6 mm Hg (n = 898), respectively. From months 2 to 12, normalisation rates (trough SeDBP <90 mm Hg) ranged from 75-85% and total responder rates (normalised or >/=10 mm Hg trough SeDBP reduction) ranged from 81-91%, while target BP was achieved in 65-75% of patients. At all time-points, most patients (>/=87%) were receiving irbesartan/HCTZ alone. Eighty-two patients (7.5%) discontinued the study due to adverse events, with half of these events considered unrelated to study medication. There were no reports of serious adverse events related to study medication. Long-term therapy with irbesartan/HCTZ is safe, well tolerated, and maintains normalised BP in >80% of patients.

Effects of metformin in patients with poorly controlled, insulin-treated type 2 diabetes mellitus. A randomized, double-blind, placebo-controlled trial

BACKGROUND

Patients with type 2 diabetes are often obese and require large doses of insulin to achieve glycemic control. Weight gain often accompanies insulin therapy and results in increasing insulin requirements.

OBJECTIVE

To evaluate the efficacy of metformin in combination with insulin in patients with type 2 diabetes poorly controlled with insulin therapy alone.

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

Outpatient diabetes clinic at a university medical center.

PATIENTS

43 patients with poorly controlled type 2 diabetes who were receiving insulin therapy.

INTERVENTION

Patients were randomly assigned to receive placebo or metformin in combination with insulin for 24 weeks.

RESULTS

Hemoglobin A1c levels decreased by 2.5 percentage points (95% CI, 1.8 to 3.1 percentage points) in the metformin group, a significantly greater change (P = 0.04) than the decrease of 1.6 percentage points in the placebo group. Average final hemoglobin A1c levels were 6.5% in the metformin group and 7.6% in the placebo group (difference, 11%). For patients who received placebo, the insulin dose increased 22.8 units (CI, 11 to 44 units) or 29% more than did the dose for patients who received metformin (P = 0.002); for these patients, the insulin dose decreased slightly. Patients in the placebo group gained an average of 3.2 kg of body weight (CI, 1.2 to 5.1 kg); patients in the metformin group gained an average of 0.5 kg of body weight (P = 0.07). Total cholesterol and low-density lipoprotein cholesterol levels decreased in both groups. High-density lipoprotein cholesterol and triglyceride levels did not change.

CONCLUSIONS

The addition of metformin to insulin therapy resulted in hemoglobin A1c concentrations that were 10% lower than those achieved by insulin therapy alone. This improvement in glycemic control occurred with the use of 29% less insulin and without significant weight gain. Metformin is an effective adjunct to insulin therapy in patients with type 2 diabetes.

A double blind comparison of the effects of amlodipine and enalapril on insulin sensitivity in hypertensive patients

This study compares the effects of a calcium channel blocker (amlodipine) and an angiotensin converting enzyme inhibitor (enalapril) on in vivo insulin sensitivity in patients with essential hypertension. Forty-six patients with mild and moderate hypertension were studied. After a 2-week single-blind placebo phase, they were randomly assigned to double-blind therapy with either amlodipine (2.5 to 10 mg/day) or enalapril (5 to 40 mg/day) for 16 weeks. Both groups were comparable in terms of demographic characteristics, degree of obesity, metabolic parameters, and arterial blood pressure. Insulin sensitivity was measured at baseline and at week 16 during the active phase using euglycemic hyperinsulinemic clamps. Arterial blood pressure decreased similarly in both groups. Whole body glucose uptake (M-value) increased with amlodipine from 3.63 +/- 0.32 (mean +/- SEM) to 3.97 +/- 0.31 mg/kg/min (P = .02). A similar tendency was observed with enalapril: from 3.59 +/- 0.32 to 3.94 +/- 0.30 mg/kg/min (P = .09). A trend to lower steady-state insulin level during the second clamp (compared to baseline) was observed in both groups. The clamp-derived insulin sensitivity index (that corrects for steady-state insulin levels and glucose levels during the clamp) increased similarly in both groups: from 1.15 +/- 0.11 to 1.39 +/- 0.13 with amlodipine (P = .03) and from 1.25 +/- 0.13 to 1.49 +/- 0.16 with enalapril (P = .01). LDL cholesterol decreased with amlodipine (mean change, -11.3 mg/dL, P = .004). Amlodipine and enalapril were associated with increments in insulin sensitivity. Amlodipine provided an additional benefit with decreased low density lipoprotein cholesterol levels.

Initial evaluation of a 290-microm diameter subcutaneous glucose sensor: glucose monitoring with a biocompatible, flexible-wire, enzyme-based amperometric microsensor in diabetic and nondiabetic humans

Results of the initial clinical evaluation in 20 human subjects of a subcutaneously implanted microsensor-based amperometrically glycemia-monitoring system, carried out between April 1994 and June 1995, are reported. The system was based on the electrical connection ("wiring") of the reaction centers of glucose oxidase to a gold electrode and on elimination of the chemicals that interfere with glucose monitoring through their horseradish peroxidase-catalyzed oxidation by internally generated hydrogen peroxide. The sensor was finer than a 29-gauge needle and had no leachable components. Because of its high selectivity for glucose, the sensor output was virtually nil at zero glucose level. This enables prompt "one-point" in vivo calibration of the sensor with a single blood glucose sample. Microsensors were subcutaneously implanted in ten nondiabetic and ten insulin-dependent diabetes mellitus (IDDM) volunteers. All subjects underwent standard meal tests and intravenous glucose-tolerance tests (IVGTT) in addition to hourly plasma glucose measurements. The sensor signals were continuously recorded, and the glucose concentration estimates were derived by calibrating the sensor using a single blood sample (one-point calibration). Regression analysis revealed that the sensor-estimated glucose concentrations were linearly related to the plasma glucose concentrations (r2 = 0.75) over a wide glucose concentration range (2-28 mmol/L) (sensor estimate = plasma 0.96 + 0.26 mmol/L). The difference between the estimated and actual glucose concentration was -0.13+/-0.23 mmol/L [mean +/-95% confidence interval (CI), n = 546], and 95% of the estimates fell in clinically acceptable zones of the Clarke error grid. The sensing delay time was 10.4+/-2.3 min as measured by the IVGTT. The subjects reported no discomfort associated with wearing the sensors.

Improved glycemic control in intensively treated type 1 diabetic patients using blood glucose meters with storage capability and computer-assisted analyses

OBJECTIVE

To determine the effect on glycemic control in intensively treated type 1 diabetic patients using a blood glucose meter with storage capability and computer-assisted analyses.

RESEARCH DESIGN AND METHODS

Glycemic control was assessed in 22 intensively treated adults with type 1 diabetes for 12 months while using a meter without memory, followed by 12 months while using a meter with memory. Log books were used to assist patients in managing aspects of the diabetes treatment plan during the first 12-month period, and computer-assisted analyses were used when the meter with memory was used. GHb levels were measured monthly throughout the 24 months of observation.

RESULTS

The mean GHb level averaged across all patients during the period of memory meter use (6.4%) was significantly lower than that during the period of meter use without memory (6.9%) (P=0.0004). The change in GHb levels from each period-specific baseline level occurred at significantly different slopes (P=0.046) when adjusted for baseline GHb level. In addition, the downward trend in GHb level was greater in those patients who increased the frequency of testing the most (r=-0.54, P=0.01).

CONCLUSIONS

Use of a meter with memory in conjunction with computer-generated analyses of stored blood glucose test results can lead to improved glycemic control when used by a group of intensively treated adult diabetic patients. Improvement in glycemic control was related to frequency of blood glucose testing.

Nephropathy and hypertension in diabetes

The treatment of the patient with diabetes, with or without hypertension, is complex and challenging. Hyperglycemic treatment should ideally not only control blood glucose, but also prevent the chronic complications and associated metabolic derangements that can lead to increased morbidity and mortality. Hypertensive treatment should not only decrease blood pressure, but also reduce the risk of macrovascular and microvascular disease. The use of antihypertensive agents that improve insulin resistance, dyslipidemia, glycemic control, and nephropathy is preferred whenever possible. The real key to success in the care of the hypertensive diabetic patient is adequate screening and appropriate, early treatment. Currently, there is ample evidence to support the use of intensive management with the goal of near-normalization of blood glucose levels in most patients with diabetes. Similarly, aggressive treatment of hypertension is the current standard. Accomplishing these goals helps to prevent the development of chronic diabetic complications, including nephropathy. ESRD need not be the inevitable outcome for individuals with early diabetic nephropathy. Interventions currently available that are targeted at the known modifiable risk factors underlying the development and progression of diabetic nephropathy offer the best hope for reducing the incidence and severity of this complication. Prevention of the complications of diabetes, including nephropathy, must be the goal for the future on behalf of all those who now have diabetes.

Double-blind randomized trial of tramadol for the treatment of the pain of diabetic neuropathy

OBJECTIVE

The objective of this study was to evaluate the efficacy and safety of tramadol in treating the pain of diabetic neuropathy.

BACKGROUND

The pain of diabetic neuropathy is a major cause of morbidity among these patients and treatment, as with other small-fiber neuropathies, is often unsatisfactory. Tramadol is a centrally acting analgesic for use in treating moderate to moderately severe pain.

METHODS

This multicenter, outpatient, randomized, double-blind, placebo-controlled, parallel-group study consisted of a washout/screening phase, during which all analgesics were discontinued, and a 42-day double-blind treatment phase. A total of 131 patients with painful diabetic neuropathy were treated with tramadol (n=65) or placebo (n=66) tramadol, which were administered as identical capsules in divided doses four times daily. The primary efficacy analysis compared the mean pain intensity scores in the tramadol and placebo groups obtained at day 42 of the study or at the time of discontinuation. Secondary efficacy assessments were the pain relief rating scores and a quality of life evaluation based on daily activities and sleep characteristics.

RESULTS

Tramadol, at an average dosage of 210 mg/day, was significantly (p < 0.001) more effective than placebo for treating the pain of diabetic neuropathy. Patients in the tramadol group scored significantly better in physical (p=0.02) and social functioning (p=0.04) ratings than patients in the placebo group. No statistically significant treatment effects on sleep were identified. The most frequently occurring adverse events with tramadol were nausea, constipation, headache, and somnolence.

CONCLUSIONS

The results of this placebo-controlled trial showed that tramadol was effective and safe in treating the pain of diabetic neuropathy.

Advantages of alpha-glucosidase inhibition as monotherapy in elderly type 2 diabetic patients

The objective of this study was to determine the safety, efficacy, and tolerability of the alpha-glucosidase inhibitor miglitol vs. the sulfonylurea glyburide in the treatment of elderly patients with type 2 diabetes mellitus, inadequately controlled by diet alone. This was a double-blind, randomized, placebo-controlled, 1-yr trial of miglitol 25 mg TID and 50 mg TID compared with placebo and a titrated dose of glyburide in a parallel group comparison study conducted in 30 out-patient sites across the United States. Four hundred eleven (411) diet-treated patients age 60 yr or greater were randomized to receive either placebo TID (n = 101), miglitol 25 mg TID (n = 104), miglitol 50 mg TID (n = 102), or a once-daily dose of glyburide titrated based on fasting plasma glucose (FPG) (n = 104), for a period of 56 weeks. Efficacy was assessed by glycated hemoglobin (HbA1c), fasting and post-meal glucose, insulin, and lipid levels, and by 24-h urinary excretion of glucose and albumin. Safety and tolerability were assessed by tabulation of adverse events, periodic laboratory determinations, and home blood glucose monitoring. HbA1c treatment effects (placebo-subtracted change in HbA1c from baseline) at the 1-yr endpoint were -0.49%, -0.40%, and -0.92% in the miglitol 25 mg TID, miglitol 50 mg TID, and glyburide groups, respectively (P < 0.05- 0.01 vs. placebo). Postprandial insulin levels were significantly greater than placebo and miglitol in the glyburide group (P < 0.01). Hypoglycemia, weight gain, and both routine and serious cardiovascular events were more frequent in the glyburide group (P < 0.05-0.01 vs. placebo or miglitol groups). Diarrhea (or soft stools) and flatulence were more common in both miglitol groups than in the other two groups in a dose-dependent manner, but resulted in relatively few study dropouts. Treatment with miglitol offers the elderly type 2 diabetic patient significant reductions in daylong glycemia as measured by HbA1c. The greater HbA1c reductions seen with once-a-day glyburide occurred at a cost of significant increases in weight, insulin levels, and the incidences of clinical and subclinical hypoglycemia, which did not occur in the miglitol groups. alpha-glucosidase inhibitors are a useful and relatively safe therapeutic option in the elderly patient with type 2 diabetes.

Obesity-independent hyperinsulinemia in nondiabetic first-degree relatives of individuals with type 2 diabetes

A close association between obesity and hyperinsulinemia is well recognized, but it is not known whether this relationship is affected by the genetic susceptibility to type 2 diabetes. Insulin response to a 75-g oral glucose load was evaluated in healthy nondiabetic Caucasians with first-degree family history of diabetes (relatives, n = 55) and those without family history (nonrelatives, n = 33). A significant correlation between the BMI and insulin response (area under the curve [AUC] during the 2-h period) was seen in nonrelatives (r = 0.68, P < 0.0001) but not in the relatives (r = 0.12, P = 0.37). Multivariate analysis revealed that obesity (BMI) was the primary determinant of insulin response in nonrelatives (P < 0.001), whereas among the relatives, BMI had no significant impact (P = 0.28). Thus, these distinctions between the relatives and nonrelatives remained after adjusting for glucose level, age, and gender. Among first-degree relatives, the commonly observed association between BMI and insulin response is lost, and hyperinsulinemia is present even in the absence of obesity. First-degree family history of diabetes may confer insulin resistance that is independent of obesity. Alternatively, this could suggest a pathological regulation of an obesity-insulin feedback loop, e.g., a defective recognition of adiposity.