The Association of Coronary Artery Calcification With Subsequent Incidence of Cardiovascular Disease in Type 1 Diabetes: The DCCT/EDIC Trials.

OBJECTIVES: This study sought to determine the relationship between coronary artery calcium (CAC) scores and subsequent cardiovascular disease (CVD) events in DCCT (Diabetes Control and Complications Trial)/EDIC (Epidemiology of Diabetes Interventions and Complications) participants. BACKGROUND: The CAC score has been validated for improved risk stratification in general populations; however, this association has not been well studied in type 1 diabetes (T1DM). METHODS: Computed tomography (CT) to measure CAC was performed in 1,205 DCCT/EDIC participants at a mean of 42.8 years of age during EDIC years 7 to 9, after the end of DCCT. This study analyzed the association between CAC and time to the first subsequent CVD event or to the first major adverse cardiac event (MACE), a follow-up of 10 to 13 years. CAC was categorized as: 0, >0 to 100, >100 to 300, or >300 Agatston units. RESULTS: Of 1,156 participants at risk for subsequent CVD, 105 had an initial CVD event (8.5 per 1,000 patient-years); and of 1,187 participants at risk for MACE, 51 had an initial MACE event (3.9 per 1,000 patient-years). Event rates among those with scores of zero (n = 817 [70.7%]) were very low for CVD (5.6 per 1,000 patient years). CAC scores >100 to 300 (hazard ratio [HR]: 4.17, 5.40) and >300 (HR: 6.06, 6.91) were associated with higher risks of CVD and MACE, respectively, compared to CAC of 0 (p < 0.0001). CAC scores >0 to 100 were nominally associated with CVD (HR: 1.71; p = 0.0415) but not with MACE (HR: 1.11; p = 0.8134). Similar results were observed when also adjusted for mean HbA1c and conventional CVD risk factors. The increment in the AUC due to CAC was modest. CONCLUSIONS: CAC scores >100 Agatston units were significantly associated with an increased risk of the subsequent occurrence of CVD and MACE in DCCT/EDIC cohort. (Diabetes Control and Complications Trial [DCCT]; NCT00360815; Epidemiology of Diabetes Interventions and Complications [EDIC]; NCT00360893).

Iatrogenic hyperinsulinemia in type 1 diabetes: its effect on atherogenic risk markers.

AIMS: Insulin is lipogenic and may invoke inflammation. We wished to determine if well controlled human and mice with type 1 diabetes had iatrogenic hyperinsulinemia as an explanation for the increased rate of coronary artery disease (CAD) in type 1 diabetes. METHODS: Type 1 diabetic subjects with HbA1C less than 7.0% had plasma insulin measured before and one hour after a Boost® challenge and a dose of subcutaneously administered insulin. These levels were compared with non-diabetic humans. Plasma insulin levels in well controlled NOD mice with type 1 diabetes were measured 3 h and 17 h after their usual dose of insulin. Hepatic cholesterol-relevant CAD and inflammation markers were measured in the NOD mice. RESULT: Marked iatrogenic hyperinsulinemia was observed in patients at levels of approximately two times higher than in non-diabetic controls. Similar findings were present in the NOD mice. Hepatic CAD risk markers were increased by insulin, but did not exceed normal expression levels in non-diabetic mice with lower insulin. In contrast, insulin-mediated stimulation of pro-inflammatory mediators TNF-α and IL-1ß remained significantly higher in hyperinsulinemic NOD than non-diabetic mice. CONCLUSION: Optimal insulin therapy in mice and humans with type 1 diabetes causes iatrogenic hyperinsulinemia and subsequently promotes pro-inflammatory macrophage response independent of hepatic cholesterol-relevant CAD markers. The tight glycemic control in type 1 diabetes may thus increase the risk for atherogenesis via inflammation.

Comparison of a novel insulin bolus-patch with pen/syringe injection to deliver mealtime insulin for efficacy, preference, and quality of life in adults with diabetes: a randomized, crossover, multicenter study.

OBJECTIVE: This study compared the efficacy, safety, device satisfaction, and quality of life (QOL) in people with diabetes using an insulin bolus-patch versus current devices (pen/syringe) to deliver mealtime insulin. RESEARCH DESIGN AND METHODS: Thirty-eight subjects with diabetes (26 with type 1 and 12 with type 2) were randomized to bolus-patch or current injection device (55% pen and 45% syringe) to deliver mealtime insulin in a multicenter, 6-week crossover study. Efficacy was assessed by equivalence in mean daily seven-point blood glucose (MDBG). Safety assessments included severe hypoglycemia episodes, adverse device effects (ADEs), and adverse events (AEs). Device satisfaction was determined by the validated Insulin Delivery System Rating Questionnaire (IDSRQ) and QOL by the validated Diabetes Specific QOL Scale (DSQOLS). RESULTS: Using bolus-patch, MDBG (mean±SE) was equivalent to that using pen/syringe (8.61±0.28 vs. 9.02±0.26 mmol/L; P=0.098). SD of the seven-point blood glucose measurements was lower using bolus-patch (3.18±0.18 vs. 3.63±0.17 mmol/L; P=0.004), as was the coefficient of variation (CV) (37.2±1.7 vs. 40.3±1.7%; P=0.046). Hemoglobin A1c, 1,5-anhydroglucitol, fructosamine, and insulin use were similar between groups. There were no severe hypoglycemia episodes or serious ADEs. Between-device AEs were comparable. Subjects scored better on six of seven subscales on the DSQOLS and five of six subscales on the IDSRQ while using bolus-patch versus pen/syringe. At study completion, 76% of subjects would choose to switch to bolus-patch (P=0.001). CONCLUSIONS: Delivery of mealtime insulin with bolus-patch compared with pen/syringe resulted in equivalent MDBG, lower SD and CV of seven-point blood glucose measurements, good safety, significant device satisfaction, and improved QOL.

Combination therapy using metformin or thiazolidinediones and insulin in the treatment of diabetes mellitus.

The biguanide, metformin, sensitizes the liver to the effect of insulin, suppressing hepatic glucose output. Thiazolidinediones such as rosiglitazone and pioglitazone enhance insulin-mediated glucose disposal, leading to reduced plasma insulin concentrations. These classes of drugs may also have varying beneficial effects on features of insulin resistance such as lipid levels, blood pressure and body weight. Metformin in combination with insulin has been shown to significantly improve blood glucose levels while lowering total daily insulin dose and body weight. The thiazolidinediones in combination with insulin have also been effective in lowering blood glucose levels and total daily insulin dose. Triple combination therapy using insulin, metformin and a thiazolidinedione improves glycaemic control to a greater degree than dual therapy using insulin and metformin or insulin and a thiazolidinedione. There is insufficient evidence to recommend the use of metformin or thiazolidinediones in type 1 diabetic patients. Although these agents are largely well tolerated, some subjects experience significant gastrointestinal problems while using metformin. Metformin is associated with a low risk of lactic acidosis, but should not be used in patients with elevated serum creatinine or those being treated for congestive heart failure. The thiazolidinediones are associated with an increase in body weight, although this can be avoided with careful lifestyle management. Thiazolidinediones may also lead to oedema and are associated with a low incidence of hepatocellular injury. Thiazolidinediones are contraindicated in patients with underlying heart disease who are at risk of congestive heart failure and in patients who have abnormal hepatic function. The desired blood glucose-lowering effect and adverse event profiles of these agents should be considered when recommending these agents to diabetic patients. The potential for metformin or the thiazolidinediones to impact long-term cardiovascular outcomes remains under investigation.

The effect of rosiglitazone on overweight subjects with type 1 diabetes.

OBJECTIVE: To evaluate the safety and effectiveness of rosiglitazone in the treatment of overweight subjects with type 1 diabetes. RESEARCH DESIGN AND METHODS: A total of 50 adult type 1 diabetic subjects with a baseline BMI > or =27 kg/m(2) were randomly assigned in a double-blind fashion to take insulin and placebo (n = 25) or insulin and rosiglitazone 4 mg twice daily (n = 25) for a period of 8 months. Insulin regimen and dosage were modified in all subjects to achieve near-normal glycemic control. RESULTS: Both groups experienced a significant reduction in HbA(1c) (A1C) level (rosiglitazone: 7.9 +/- 1.3 to 6.9 +/- 0.7%, P < 0.0001; placebo: 7.7 +/- 0.8 to 7.0 +/- 0.9%, P = 0.002) and a significant increase in weight (rosiglitazone: 97.2 +/- 11.8 to 100.6 +/- 16.0 kg, P = 0.008; placebo: 96.4 +/- 12.2 to 99.1 +/- 15.0, P = 0.016). Baseline measures of BMI (P = 0.001), total daily insulin dose (P = 0.002), total cholesterol (P = 0.005), HDL cholesterol (P = 0.001), and LDL cholesterol (P = 0.02) were predictors of improvement in A1C level only in the group treated with rosiglitazone. Total daily insulin dose increased in subjects taking placebo (74.0 +/- 33.8 to 82.0 +/- 48.9 units, P < 0.05 baseline vs. week 32), but it decreased slightly in subjects taking rosiglitazone (77.5 +/- 28.6 to 75.3 +/- 33.1 units). Both systolic blood pressure (137.4 +/- 15.6 vs. 128.8 +/- 14.8 mmHg, baseline vs. week 32, P < 0.02) and diastolic blood pressure (87.2 +/- 9.4 vs. 79.4 +/- 7.2 mmHg, P < 0.0001) improved in the group treated with rosiglitazone. The total incidence of hypoglycemia did not differ between groups. CONCLUSIONS: Rosiglitazone in combination with insulin resulted in improved glycemic control and blood pressure without an increase in insulin requirements, compared with insulin- and placebo-treated subjects, whose improved glycemic control required an 11% increase in insulin dose. Weight gain and hypoglycemia were similar in both groups at the end of the study. The greatest effect of rosiglitazone occurred in subjects with more pronounced markers of insulin resistance.

Improved glycemic control without weight gain using triple therapy in type 2 diabetes.

OBJECTIVE: To evaluate the safety and effectiveness of triple therapy using insulin, metformin, and a thiazolidinedione following a course of dual therapy using insulin and metformin or insulin and a thiazolidinedione in type 2 diabetes. RESEARCH DESIGN AND METHODS: Twenty-eight type 2 diabetic subjects using insulin monotherapy (baseline HbA(lc) level 8.5%) who had been randomly assigned to insulin (INS) and metformin (MET) (INS + MET, n = 14) or INS and the thiazolidinedione troglitazone (TGZ) (INS + TGZ, n = 14) (dual therapy) for 4 months were given INS, MET, and TGZ (triple therapy: INS + MET, add TGZ; or INS + TGZ, add MET) for another 4 months. The INS dose was not increased. RESULTS: HbA(1c) levels decreased in both groups during dual therapy and improved further during triple therapy (INS + MET 7.0 +/- 0.8, INS + TGZ 6.2 +/- 0.8, P < 0.0001; INS + MET, add TGZ 6.1 +/- 0.4%, P < 0.001; INS + TGZ, add MET 5.8 +/- 0.6%, P < 0.05; and INS + TGZ vs. INS + MET, P = 0.02). Significant reductions in total daily insulin dose occurred in the INS + TGZ (-14.1 units, P < 0.0001), INS + TGZ add MET (-13.7 units, P < 0.01), and the INS + MET add TGZ groups (-17.3 units, P < 0.003), but not in the INS + MET group (-3.2 units) (INS + TGZ vs. INS + MET P < 0.05). Subjects in the INS + TGZ group experienced significant weight gain (4.4 +/- 2.7 kg, P < 0.0005). No weight gain occurred in the INS + MET, INS + MET add TGZ, and INS + TGZ add MET groups. CONCLUSIONS: Triple therapy using INS, MET, and TGZ resulted in lower HbA(lc) levels and total daily insulin dose than during dual therapy. The use of triple therapy resulted in 100% of subjects achieving an HbA(lc) <7.0%, while decreasing the dose of INS. Weight gain was avoided when MET therapy preceded the addition of TGZ therapy. The addition of TGZ resulted in the greatest reductions in HbA(lc) levels and insulin dose. Triple therapy using INS, MET, and a thiazolidinedione (such as TGZ) can be a safe and effective treatment in type 2 diabetes.

Comparison of insulin monotherapy and combination therapy with insulin and metformin or insulin and troglitazone in type 2 diabetes.

OBJECTIVE: To evaluate the safety and efficacy of treatment with insulin alone, insulin plus metformin, or insulin plus troglitazone in individuals with type 2 diabetes. RESEARCH DESIGN AND METHODS: A total of 88 type 2 diabetic subjects using insulin monotherapy (baseline HbA(lc) 8.7%) were randomly assigned to insulin alone (n = 31), insulin plus metformin (n = 27), or insulin plus troglitazone (n = 30) for 4 months. The insulin dose was increased only in the insulin group. Metformin was titrated to a maximum dose of 2,000 mg and troglitazone to 600 mg. RESULTS: HbA(lc) levels decreased in all groups, the lowest level occurring in the insulin plus troglitazone group (insulin alone to 7.0%, insulin plus metformin to 7.1%, and insulin plus troglitazone to 6.4%, P < 0.0001). The dose of insulin increased by 55 units/day in the insulin alone group (P < 0.0001) and decreased by 1.4 units/day in the insulin plus metformin group and 12.8 units/day in the insulin plus troglitazone group (insulin plus metformin versus insulin plus troglitazone, P = 0.004). Body weight increased by 0.5 kg in the insulin plus metformin group, whereas the other two groups gained 4.4 kg (P < 0.0001 vs. baseline). Triglyceride and VLDL triglyceride levels significantly improved only in the insulin plus troglitazone group. Subjects taking metformin experienced significantly more gastrointestinal side effects and less hypoglycemia. CONCLUSIONS: Aggressive insulin therapy significantly improved glycemic control in type 2 diabetic subjects to levels comparable with those achieved by adding metformin to insulin therapy. Troglitazone was the most effective in lowering HbA(lc), total daily insulin dose, and triglyceride levels. However, treatment with insulin plus metformin was advantageous in avoiding weight gain and hypoglycemia.