Optimizing Diabetes Care Through Listening to Multiple Voices.

This article is adapted from the address Dr. Caballero delivered as the recipient of the American Diabetes Association's Outstanding Educator in Diabetes Award for 2023. He delivered the address in June 2023 during the Association's 83rd Scientific Sessions in San Diego, CA. A webcast of this speech is available for viewing on the DiabetesPro website (https://events.diabetes.org/live/25/page/186).

Implicit or Unconscious Bias in Diabetes Care.

"Implicit bias," also called "unconscious bias," refers to associations outside of conscious awareness that adversely affect one's perception of a person or group. Awareness of implicit bias has been increasing in the realm of diabetes care. Here, the authors highlight several types of unconscious bias on the part of clinicians and patients, including biases based on race, ethnicity, and obesity. They discuss how these biases can negatively affect patient-centered clinical interactions and diabetes care delivery, and they recommend implementation of evidence-based interventions and other health system policy approaches to reduce the potential impact of such biases in health care settings.

Impact of Monthly A1C Values Obtained at Home on Glycemic Control in Patients With Type 2 Diabetes: A Randomized Clinical Trial.

The purpose of this randomized controlled clinical trial was to determine whether an A1C value obtained at home by participants followed by a phone discussion of the result with a clinician would lead to 1) a more rapid and significant decrease in A1C, 2) more effective advancement of diabetes treatment, and 3) improvement in diabetes self-care behaviors. The study included 307 participants with type 2 diabetes, most of whom were of Latino origin. All study participants experienced a statistically significant reduction in mean A1C (control subjects -0.3%, P = 0.04; intervention subjects -0.5%, P = 0.0002), but there was a statistically significant difference in the number of people who achieved a reduction of ≥0.5% by 6 months, favoring the intervention (33.6 vs. 46.7%, P = 0.05).

A multinational observational study assessing insulin use: Understanding the determinants associated with progression of therapy.

AIMS: To describe global patterns of insulin treatment and to assess the impact of patient, provider, health system and economic influences on treatment decisions for patients with insulin-treated type 2 diabetes (T2D). METHODS: This prospective cohort study of insulin-treated patients with T2D was conducted across 18 countries categorized as high, upper-middle or lower-middle income regions. Information collected from patients included knowledge of diabetes, experiences and interactions with their healthcare provider. Physician information included specialty, practice size, availability of diabetes support services, volume of diabetes patients treated and time spent per patient. Physicians determined an individualized haemoglobin A1c (HbA1c) target for each patient by the start of the study. Changes in T2D therapies and HbA1c were recorded for 2 years. RESULTS: Complete treatment data were available for 2528 patients. Median age was 61 years and median duration of diabetes was 11.4 years. Changes to treatment regimen occurred in 90.0% of patients, but changes were less common in countries with a higher economic status (P < 0.001). Most treatment changes involved insulin, with changes in dose the most common. Overall predictors of change in insulin therapy included younger age, use of any insulin regimen other than basal only, higher mean baseline HbA1c and longer duration of T2D. HbA1c levels remained constant regardless of regional economic status. At baseline, 20.6% of patients were at their HbA1c target; at 2 years this was 26.8%. CONCLUSIONS: Among insulin-treated patients with T2D, treatment changes were common; however, only approximately one-fourth of individuals achieved their HbA1c target.

Diabetes subgroups and sociodemographic inequalities in Mexico: a cross-sectional analysis of nationally representative surveys from 2016 to 2022.

Background: Differences in the prevalence of four diabetes subgroups have been reported in Mexico compared to other populations, but factors that may contribute to these differences are poorly understood. Here, we estimate the prevalence of diabetes subgroups in Mexico and evaluate their correlates with indicators of social disadvantage using data from national representative surveys. Methods: We analyzed serial, cross-sectional Mexican National Health and Nutrition Surveys spanning 2016, 2018, 2020, 2021, and 2022, including 23,354 adults (>20 years). Diabetes subgroups (obesity-related [MOD], severe insulin-deficient [SIDD], severe insulin-resistant [SIRD], and age-related [MARD]) were classified using self-normalizing neural networks based on a previously validated algorithm. We used the density-independent social lag index (DISLI) as a proxy of state-level social disadvantage. Findings: We identified 4204 adults (median age: 57, IQR: 47-66, women: 64%) living with diabetes, yielding a pooled prevalence of 16.04% [95% CI: 14.92-17.17]. When stratified by diabetes subgroup, prevalence was 6.62% (5.69-7.55) for SIDD, 5.25% (4.52-5.97) for MOD, 2.39% (1.95-2.83) for MARD, and 1.27% (1.00-1.54) for SIRD. SIDD and MOD clustered in Southern Mexico, whereas MARD and SIRD clustered in Northern Mexico and Mexico City. Each standard deviation increase in DISLI was associated with higher odds of SIDD (OR: 1.12, 95% CI: 1.06-1.12) and lower odds of MOD (OR: 0.93, 0.88-0.99). Speaking an indigenous language was associated with higher odds of SIDD (OR: 1.35, 1.16-1.57) and lower odds of MARD (OR 0.58, 0.45-0.74). Interpretation: Diabetes prevalence in Mexico is rising in the context of regional and sociodemographic inequalities across distinct diabetes subgroups. SIDD is a subgroup of concern that may be associated with inadequate diabetes management, mainly in marginalized states. Funding: This research was supported by Instituto Nacional de Geriatría in Mexico.

Impact of race/ethnicity on efficacy and safety of two starter insulin regimens in patients with type 2 diabetes: a posthoc analysis of the DURABLE trial.

OBJECTIVE: To explore the impact of race/ethnicity on efficacy and safety of twice-daily insulin lispro mix 75/25 (LM75/25; 75% lispro protamine suspension, 25% insulin lispro) and once daily insulin glargine (GL). DESIGN, SETTING, PATIENTS: More than 2,000 Patients with type 2 diabetes enrolled in the 24-week initiation phase of the DURABLE Trial. MAIN OUTCOME MEASURES: Efficacy and safety variables at endpoint, including hemoglobin A1c (HbA1c), self-monitored plasma glucose (SMPG), and hypoglycemia, in each racial/ethnic group were compared to Caucasians within treatment groups. RESULTS: Asian patients had less (LM75/25: -1.46%, P < .01; GL: -1.25%, P < .01) and Hispanic patients had greater (LM75/25: -2.17%) HbA1c reduction from baseline vs Caucasian patients (LM75/25: -1.84%; GL: -1.78%). Fewer Asian (LM75/25: 20%, P < .001; GL: 22%, P < .001) and Hispanic patients (LM75/25: 40%, P < .01) reached HbA1c target (< 7%) vs Caucasian patients (LM75/25: 53%; GL: 44%). Fasting plasma glucose was similar among groups, postprandial glucose (PPG) with GL was lower for African patients post-breakfast and post-dinner and higher for Asian patients post-lunch. Only PPG with LM75/25 was lower for Hispanic patients post-breakfast. Weight gain was lower in Asian patients (LM75/ 25). Insulin dose was higher for Asian (LM75/25 and GL) and lower for African patients (GL). Hypoglycemia rate was lower for Asian (LM75/25 and GL) and Hispanic patients (LM75/25). CONCLUSIONS: There were significant efficacy and safety differences among racial/ethnic groups in the DURABLE trial. These differences may be important in designing insulin based treatment plans.

Individualized HbA1c target selection and achievement in the Multinational Observational Study Assessing Insulin Use (MOSA1c) type 2 diabetes study.

AIM: To identify which individual-, physician-, and the healthcare system-related factors can predict individualized hemoglobin A1c (HbA1c) targets and the likelihood of reaching those targets after initial insulin therapy over a two-year follow-up period. METHODS: Real-world data, including baseline characteristics of people with type 2 diabetes mellitus (T2DM), psychosocial data, and diabetes medication use, collected from the Multinational Observational Study Assessing Insulin Use (MOSA1c) study in 18 countries were analyzed. RESULTS: Overall, 225 of 1194 people with T2DM (18.8%) who received initial insulin therapy for ≥3 months reached HbA1c targets at two-year follow-up; most were likely to be White (64.9%) and perceptions of their relationship with physicians were less positive than those who did not reach HbA1c targets. Higher baseline HbA1c (>8%) was the strongest predictor of being assigned an HbA1c target >7% (odds ratio [OR] 6.06, 95% confidence interval [CI] 3.97, 9.26). A smaller difference between baseline and target HbA1c levels was the strongest predictor of reaching an HbA1c target at two-year follow-up (large vs small difference, OR 0.28, 95% CI 0.17, 0.47). CONCLUSIONS: Several factors were significantly associated with establishing individualized HbA1c targets and reaching these targets. A small proportion of people with T2DM on insulin therapy reached their HbA1c target. Personalized management of glycemic targets necessitates the adoption of multi-factorial strategies, as several factors could influence an individual's glycemic outcome. CLINICALTRIALS. GOV IDENTIFIER: NCT01400971.

Genetic Ancestry Markers and Difference in A1c Between African American and White in the Diabetes Prevention Program.

Purpose: HbA1c levels are higher in blacks than non-Hispanic whites (NHWs). We investigated whether genetics could explain this difference in Diabetes Prevention Program (DPP) participants. Methods: We tested (i) genetic variants causing hemoglobinopathies, (ii) a genetic risk score (GRS) based on 60 variants associated with HbA1c from genome-wide association meta-analysis, and (iii) principal component (PC) factors that capture continental ancestry derived from genetic markers distributed across the genome. Results: Of 2658 eligible DPP participants, 537 (20%) self-identified as black and 1476 (56%) as NHW. Despite comparable fasting and 2-hour glucose levels, blacks had higher HbA1c (mean ± SD = 6.2 ± 0.6%) compared with NHWs (5.8 ± 0.4%; P < 0.001). In blacks, the genetic variant causing sickle cell trait was associated with higher HbA1c [ß (SE) = +0.44 (0.08)%; P = 2.1 × 10-4]. The GRS was associated with HbA1c in both blacks and NHWs. Self-identified blacks were distributed along the first PC axis, as expected in mixed ancestry populations. The first PC explained 60% of the 0.4% difference in HbA1c between blacks and NHWs, whereas the sickle cell variant explained 16% and GRS explained 14%. Conclusions: A large proportion of HbA1c difference between blacks and NHWs was associated with the first PC factor, suggesting that unidentified genetic markers influence HbA1c in blacks in addition to nongenetic factors.

The "A to Z" of Managing Type 2 Diabetes in Culturally Diverse Populations.

Type 2 diabetes affects racial/ethnic minorities at an alarming rate in the US and in many countries around the world. The quality of health care provided to these groups is often suboptimal, resulting in worse patient-related outcomes when compared to those in mainstream populations. Understanding the complex biological elements that influence the development and course of the disease in high-risk populations is extremely important but often insufficient to implement effective prevention and treatment plans. Multiple factors must be addressed in routine diabetes clinical care. This paper discusses various key factors, organized in alphabetical order. These are acculturation, biology, clinician's cultural awareness, depression and diabetes-specific emotional distress, educational level, fears, group integration, health literacy, intimacy and sexual dysfunction, judging, knowledge of the disease, language, medication adherence, nutritional preferences, other forms of medicine (alternative), perception of body image, quality of life, religion and faith, socio-economic status, technology, unconscious bias, vulnerable groups, asking why?, exercise, "you are in charge" and zip it! Considering these factors in the development of type 2 diabetes prevention and treatment programs will help improve diabetes-related outcomes in culturally diverse populations and reduce health care disparities.

Long-term studies of treatments for type 2 diabetes.

There is a relative lack of long-term data for individual glucose-lowering therapies for the treatment of type 2 diabetes mellitus. A systematic search of published literature reporting data of approximately ≥3 years of follow-up from randomized controlled trials and their extensions was conducted. Trials to evaluate the efficacy and/or safety of glucose-lowering drugs currently approved for the treatment of adults with type 2 diabetes were included. Search results included long-term published data for traditional oral glucose-lowering drugs, insulin, α-glucosidase inhibitors, and incretin-based therapies. In general, results indicated that the short-term risk/benefit profile of these therapies is in line with longer-term evaluations. Individual results from these trials are reviewed in this report. These findings support the use of approved drug classes for longer-term treatment of type 2 diabetes.

The effect of vitamin E on endothelial function of micro- and macrocirculation and left ventricular function in type 1 and type 2 diabetic patients.

We examined the effects of high-dosage vitamin E treatment over a 12-month period on the vascular reactivity of micro- and macrocirculation and left ventricular function in diabetic patients. Subjects (n = 89) were randomized to vitamin E (1,800 IU daily) or placebo and were followed for 12 months. High-resolution ultrasound images were used to measure the flow-mediated dilation (FMD; endothelium dependent) and nitroglycerin-induced dilation (NID; endothelium independent) of the brachial artery. Laser Doppler perfusion imaging was used to measure vascular reactivity in the forearm skin. Left ventricular function was evaluated using transthoracic echocardiogram. At the end of the 6-month period, a worsening in endothelium-dependent skin vasodilation (P = 0.02) and rise in endothelin levels (P = 0.01) were found in the vitamin E compared with the placebo group. At the end of the 12-month period, a worsening was observed in NID (P = 0.02) and a marginal worsening was seen in systolic blood pressure (P = 0.04) and FMD (P = 0.04) in the vitamin E compared with the placebo group. In addition C-reactive protein levels decreased marginally in the vitamin E compared with the placebo group (P = 0.05). No changes were observed in left ventricular function. We concluded that long-term treatment with 1,800 IU of vitamin E has no beneficial effects on endothelial or left ventricular function in diabetic patients. Because vitamin E-treated patients had a worsening in some vascular reactivity measurements when compared with control subjects, the use of high dosages of vitamin E cannot be recommended.

Building cultural bridges: understanding ethnicity to improve acceptance of insulin therapy in patients with type 2 diabetes.

OBJECTIVES: Type 2 diabetes is a significant healthcare problem in the Latino/Hispanic community. As with most patients with type 2 diabetes, Latino patients will eventually require insulin therapy to maintain glycemic control. Some cultural barriers to starting insulin therapy among Latino patients have been reported. This review explores the implications of the increasing prevalence of type 2 diabetes in Latino patients, defines cultural values and differences that may affect acceptance of insulin therapy, and reviews available strategies that may facilitate initiation of insulin treatment in this group. METHODS: A literature search was conducted for publications related to Hispanic Americans, Latino persons, type 2 diabetes, and insulin therapy by using PubMed/National Center for Biotechnology Information. RESULTS: Despite evidence that earlier initiation of insulin therapy improves outcomes in patients with type 2 diabetes, Latino patients appear to be more resistant to insulin therapy than non-Hispanic Whites. Physician challenges associated with addressing the negative perceptions about insulin therapy are further compounded by cultural and language barriers often encountered when treating Latino patients. Scarce information regarding specific insulin regimens in Latino patients is available. CONCLUSIONS: Increased cultural awareness and competence among healthcare providers and increased use of Spanish-speaking diabetes educators seem to improve diabetes outcomes among Latino patients. Also, implementation of simpler insulin regimens may increase acceptance of insulin therapy and improve clinical outcomes in Latino patients. A relatively simple titration regimen using once-daily bedtime basal insulin glargine has demonstrated efficacy for improving glycemic control in many patients with type 2 diabetes and is a strategy that may also be useful for Latinos as an introduction to insulin therapy and as the foundation of a more comprehensive insulin regimen in the future.

Linagliptin plus metformin in patients with newly diagnosed type 2 diabetes and marked hyperglycemia.

OBJECTIVES: Few studies of oral glucose-lowering drugs exist in newly diagnosed type 2 diabetes (T2D) patients with marked hyperglycemia, and insulin is often proposed as initial treatment. We evaluated the oral initial combination of metformin and linagliptin, a dipeptidyl peptidase-4 inhibitor, in this population. METHODS: We performed a pre-specified subgroup analysis of a randomized study in which newly diagnosed T2D patients with glycated hemoglobin A1c (HbA1c) 8.5%-12.0% received linagliptin/metformin or linagliptin monotherapy. Subgroups of baseline HbA1c, age, body-mass index (BMI), renal function, race, and ethnicity were evaluated, with efficacy measured by HbA1c change from baseline after 24 weeks. RESULTS: HbA1c reductions from baseline (mean 9.7%) at week 24 in the overall population were an adjusted mean -2.81% ± 0.12% with linagliptin/metformin (n = 132) and -2.02% ± 0.13% with linagliptin (n = 113); treatment difference -0.79% (95% CI -1.13 to -0.46, P < 0.0001). In patients with baseline HbA1c ≥9.5%, HbA1c reduction was -3.37% with linagliptin/metformin (n = 76) and -2.53% with linagliptin (n = 61); difference -0.84% (95% CI -1.32 to -0.35). In those with baseline HbA1c <9.5%, HbA1c reduction was -2.08% with linagliptin/metformin (n = 56) and -1.39% with linagliptin (n = 52); difference -0.69% (95% CI -1.23 to -0.15). Changes in HbA1c and treatment differences between the linagliptin/metformin and linagliptin groups were of similar magnitudes to the overall population across patient subgroups based on age, BMI, renal function, and race. Drug-related adverse events occurred in 8.8% and 5.7% of linagliptin/metformin and linagliptin patients, respectively; no severe hypoglycemia occurred. CONCLUSION: Linagliptin/metformin combination in newly diagnosed T2D patients with marked hyperglycemia was well tolerated and elicited substantial improvements in glycemic control regardless of baseline HbA1c, age, BMI, renal function, or race. Thus, newly diagnosed, markedly hyperglycemic patients may be effectively treated by combinations of oral agents. CLINICAL TRIAL REGISTRATION: www.clinicaltrials.gov identifier is NCT01512979.

Metabolic and vascular abnormalities in subjects at risk for type 2 diabetes: the early start of a dangerous situation.

Various groups at risk for type 2 diabetes have been identified, including individuals with family history of type 2 diabetes, obesity, prior gestational diabetes, polycystic ovary syndrome, metabolic syndrome, hypertension, dyslipidemia and particularly those with pre-diabetes (impaired glucose tolerance and/or impaired fasting glucose). To various degrees, all these groups have also been identified with significant vascular abnormalities that range from endothelial dysfunction and low-grade or sub-clinical inflammation to evident atherosclerosis. The mechanisms involved in establishing a link between the risk of type 2 diabetes and vascular dysfunction are multiple and complex. The presence in the circulation of various cytokines, hormones and substrates associated with increased visceral fat and insulin resistance, the frequent appearance of associated cardiovascular risk factors and/or the possibility of some genetically determined intrinsic vascular abnormalities are all explanatory mechanisms that are being evaluated in clinical research. Whereas the possibility of appreciating a significant reduction in cardiovascular outcomes in long-term prospective clinical trials in all these groups at risk for type 2 diabetes is still lacking, understanding these mechanisms and recognizing how various interventions may improve vascular health is a worthwhile area of research that may translate into important clinical strategies to reduce the burden of type 2 diabetes and cardiovascular disease.

Lifestyle modification improves endothelial function in obese subjects with the insulin resistance syndrome.

OBJECTIVE: Endothelial dysfunction has been reported in type 2 diabetic patients and in obese subjects with insulin resistance syndrome (IRS). This study evaluates the effects of weight reduction and exercise on vascular reactivity of the macro- and the microcirculation in obese subjects with IRS. RESEARCH DESIGN AND METHODS; We studied 24 obese subjects (9 men and 15 women, age 49.3 +/- 1.9 years, BMI 36.7 +/- 0.94 kg/m(2), mean +/- SEM) with IRS at baseline and after 6 months of weight reduction and exercise. Brachial artery flow-mediated dilation (FMD) and response to sublingual glyceryltrinitrate (GTN) were assessed by high-resolution ultrasound. Microvascular reactivity was evaluated by the laser-Doppler perfusion imaging after iontophoresis of acetylcholine and sodium nitroprusside. We also measured plasma levels of soluble intercellular adhesion molecule (sICAM), vascular adhesion molecule, von Willebrand factor, plasminogen activator inhibitor-1 (PAI-1) antigen, and tissue plasminogen activator antigen. RESULTS: This intervention resulted in 6.6 +/- 1% reduction in body weight (P < 0.001) and significant improvement of insulin sensitivity index (2.9 +/- 0.36 vs. 1.9 +/- 0.33 [10(-4) x min(-1) x ( microU ml(-1))], P < 0.001). FMD significantly improved (12.9 +/- 1.2% vs. 7.9 +/- 1.0%, P < 0.001), whereas response to GTN and microvascular reactivity did not change. Similar observations were seen when the subjects were subclassified according to their glucose tolerance to normal glucose tolerance, impaired glucose tolerance, and type 2 diabetes. sICAM and PAI-1 significantly decreased (251.3 +/- 7.7 vs. 265.6 +/- 9.3 ng/ml, P = 0.018 and 36.2 +/- 3.6 vs. 48.6 +/- 3.9 ng/ml, P = 0.001, respectively). The relationship between percentage weight reduction and improved FMD was linear (R(2) = 0.47, P = 0.001). CONCLUSIONS: We conclude that 6 months of weight reduction and exercise improve macrovascular endothelial function and reduces selective markers of endothelial activation and coagulation in obese subjects with IRS regardless of the degree of glucose tolerance.

Severe Ketoacidosis (pH ≤ 6.9) in Type 2 Diabetes: More Frequent and Less Ominous Than Previously Thought.

Diabetic ketoacidosis is a life-threatening acute metabolic complication of uncontrolled diabetes. Severe cases of DKA (pH ≤ 7.00, bicarbonate level ≤ 10.0, anion gap > 12, positive ketones, and altered mental status) are commonly encountered in patients with type 1 diabetes and are thought to carry an ominous prognosis. There is not enough information on the clinical course of severely acidotic type 2 diabetes (pH ≤ 6.9) patients with DKA, possibly because this condition is rarely seen in developed countries. In this series, we present 18 patients with type 2 diabetes, DKA, and a pH ≤ 6.9 that presented to a tertiary university hospital over the past 11 years. The objective was to describe their clinical characteristics, the triggering cause, and emphasis on treatment, evolution, and outcomes. The majority of the patients were female (61%). Mean age was 40.66 years (23-59). The patients had been first diagnosed with type 2 diabetes on average 5.27 ± 3.12 years before admission. Glutamic acid decarboxylase (GAD65) antibodies were negative in all patients. The origin of DKA could be attributed to two main causes: treatment omission in 8 (44.4%) patients and infections in 7 (38.8%) patients. The most common symptoms described were general malaise, dyspnea, altered mental status, and abdominal pain. Mean serum glucose on admission was 613.8 ± 114.5 mg/dL. Mean venous pH was 6.84 ± 0.03 with an anion gap of 30.3 ± 2.9 and a venous HCO3 level of 3.62 ± 1.35 mmol/L. All patients had acute renal failure on admission, with a mean serum creatinine of 1.57 ± 0.35 mg/dL compared to 0.55 ± 0.21 mg/dL at discharge. All patients received regular insulin infusion, aggressive fluid repletion, and 12 patients (66%) received bicarbonate infusion. Mean total insulin infusion dose was 181.7 ± 90.4 U (on average 0.14 ± 0.05 U/Kg/h). Mean time on infusion was 24.4 ± 12.6 hours. We recorded no mortality in this case series. Mean in-hospital stay was 5.0 ± 4.1 days. In conclusion, very severe DKA in type 2 diabetes is not uncommon in our population, shares many features with non-very-severe cases of DKA (bicarbonate therapy did not make a difference in mortality), and can be managed following standard published or institutional guidelines.

The differential effects of metformin on markers of endothelial activation and inflammation in subjects with impaired glucose tolerance: a placebo-controlled, randomized clinical trial.

The effect of metformin (1000 mg twice a day) on markers of endothelial activation, inflammation, and coagulation was investigated in subjects with impaired glucose tolerance (IGT) in a 16-wk, randomized, placebo-controlled, double-blind study. Soluble intercellular adhesion molecule, soluble vascular cell adhesion molecule, C-reactive protein, TNFalpha, von Willebrand factor, and tissue plasminogen activator were measured at baseline and at the end of the trial. Subjects with IGT (n = 55, 14 males and 41 females), aged 48.4 +/- 9.6 yr with a body mass index of 31.4 +/- 5.6 kg/m(2), were studied. All participants followed a 1-month stabilization period in their diet and physical activity. Afterward, 29 subjects were assigned to the treatment group and 26 to the control group. A significant reduction in weight, fasting plasma glucose, soluble intercellular adhesion molecule (306 +/- 75 vs. 268 +/- 61 ng/ml, P = 0.029), soluble vascular cell adhesion molecule (595 +/- 114 vs. 508 +/- 126 ng/ml, P = 0.006), and von Willebrand factor (124 +/- 34 vs. 94 +/- 34%, P = 0.001) was seen in the treatment group, whereas tissue plasminogen activator, TNFalpha, and C-reactive protein levels did not change. No change was seen in the control group. Thus, metformin improves the plasma levels of some markers of endothelial activation and coagulation in subjects with IGT, whereas it has no effect on markers of inflammation.

The effects of troglitazone, an insulin-sensitizing agent, on the endothelial function in early and late type 2 diabetes: a placebo-controlled randomized clinical trial.

Activation of the peroxisome proliferator-activator receptor gamma (PPARgamma) improves insulin resistance and glycemic control in patients with diabetes. As PPARgamma is expressed in the endothelial cell, we have investigated the effect of troglitazone, a PPARgamma activator, on the endothelial function in people with type 2 diabetes in a 12-week, prospective, randomized, double-blinded clinical trial. We studied 87 type 2 diabetic patients who were divided into 3 groups. Group A consisted of 27 patients with recently diagnosed diabetes and no clinical manifestations of macrovascular disease; group B, 29 patients with long-term diabetes and no clinically evident macrovascular disease; and group C, 31 diabetic patients with documented macrovascular disease (cardiovascular, cerebrovascular, or peripheral vascular disease). High-resolution ultrasound images were used to measure the flow-mediated dilation (FMD, endothelium-dependent) and nitroglycerin-induced dilation (NID, endothelium-independent) in the brachial artery. Laser Doppler perfusion imaging was used to measure vasodilation in the forearm skin in response to iontophoresis of 1% acetylcholine (Ach, endothelium-dependent) and 1% sodium nitroprusside (NaNP, endothelium-independent). The plasma concentrations of von Willebrand factor (vWF), soluble intercellular adhesion molecule (sICAM), and soluble vascular cell adhesion molecule (sVCAM) were also measured as indicators of endothelial cell activation. The FMD improved in the troglitazone-treated patients in group A (7.72 +/- 3.4 v 5.27 +/- 2.0, P <.05 [exit visit v baseline, percent of increase in brachial artery diameter, mean +/- SD]). The fasting insulin level also improved in this group (15.6 +/- 10 v 19.7 +/- 10, P <.05) and was strongly correlated to changes in FMD (r = -.73, P <.01). No changes were found in the FMD or the fasting insulin levels in the troglitazone-treated patients in groups B or C. The NID was not changed by troglitazone treatment in any of the 3 groups. Also, no differences were found in the microcirculation reactivity measurements or in the biochemical markers of endothelial dysfunction in all 3 groups. A small, but significant, improvement of the FMD was found in placebo-treated patients in group B, probably related to the low FMD levels at baseline in the patients (5.40 +/- 3.0 v 4.36 +/- 2.4, P <.05). We concluded that troglitazone treatment for 12 weeks improved endothelial function in the macrocirculation of patients with recently diagnosed type 2 diabetes and no clinical evidence of macrovascular disease. This improvement was strongly associated with the improvement of fasting plasma insulin concentrations.