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.

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).

Institutional experience on the impact of glucagon-like peptide-1 agonists (GLP-1) on glycemic control and weight loss in patients with type 2 diabetes at the Dubai Diabetes Center, United Arab Emirates

AIMS

To describe the effect of three classes of GLP1 analogues on HbA1c and weight over one year in a homogenous group of patients at the Dubai Diabetes Center in Dubai, United Arab Emirates. The specific objectives are to study the extent of change in HbA1c and weight loss on these medications as well as the sustainability of change over one year.

METHODS

A retrospective audit of patients diagnosed Type 2 diabetes receiving one of the three following GLP-1 agonists (Exenatide LA 2 mg weekly, liraglutide 1.8 mg once daily, Dulaglutide 1.5 mg) over one year and documenting changes in HbA1c and weight at 3-, 6-, 9-, and 12-months intervals.

RESULTS

The study shows that while there was significant reduction in HbA1c and weight in the first 3 months, this change was not clinically significant. Also, the change was not maintained at the end of the year. By the final quarter, the effect of the medication diminishes, accompanied by a partial regain of weight.

CONCLUSION

GLP1 agonists favorable initial effect on HbA1c and weight may not be sustainable beyond a certain period. The exact reason and factors contributing to this need further exploration.

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.

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.

COVID-19 in people living with diabetes: An international consensus

The COVID-19 pandemic has added an enormous toll to the existing challenge of diabetes care world-wide. A large proportion of patients with COVID-19 requiring hospitalization and/or succumbing to the disease have had diabetes and other chronic conditions as underlying risk factors. In particular, individuals belonging to racial/ethnic minorities in the U.S. and other countries have been significantly and disproportionately impacted. Multiple and complex socioeconomic factors have long played a role in increasing the risk for diabetes and now for COVID-19. Since the pandemic began, the global healthcare community has accumulated invaluable clinical experience on providing diabetes care in the setting of COVID-19. In addition, understanding of the pathophysiological mechanisms that link these two diseases is being developed. The current clinical management of diabetes is a work in progress, requiring a shift in patient-provider interaction beyond the walls of clinics and hospitals: the use of tele-medicine when feasible, innovative patient education programs, strategies to ensure medication and glucose testing availability and affordability, as well as numerous ideas on how to improve meal plans and physical activity. Notably, this worldwide experience offers us the possibility to not only prepare better for future disasters but also transform diabetes care beyond the COVID-19 era.

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.

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 [β (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.

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.

Initial combination of linagliptin and metformin compared with linagliptin monotherapy in patients with newly diagnosed type 2 diabetes and marked hyperglycaemia: a randomized, double-blind, active-controlled, parallel group, multinational clinical trial

AIMS

To evaluate glucose-lowering treatment strategies with linagliptin and metformin in people with newly diagnosed type 2 diabetes and marked hyperglycaemia, a prevalent population for which few dedicated studies of oral antidiabetes drugs have been conducted.

METHODS

A total of 316 patients, with type 2 diabetes diagnosed for ≤12 months and with glycated haemoglobin (HbA1c) concentration in the range 8.5-12.0%, were randomized 1:1 to double-blind, free-combination treatment with linagliptin 5 mg once daily and metformin twice daily (uptitrated to 2000 mg/day maximum) or to linagliptin monotherapy. The primary endpoint was change in HbA1c concentration from baseline at week 24 (per-protocol completers' cohort: n = 245).

RESULTS

The mean (standard deviation) age and HbA1c at baseline were 48.8 (11.0) years and 9.8 (1.1)%, respectively. At week 24, the mean ± standard error (s.e.) HbA1c decreased from baseline by -2.8 ± 0.1% with linagliptin/metformin and -2.0 ± 0.1% with linagliptin; a treatment difference of -0.8% (95% confidence interval -1.1 to -0.5; p <0.0001). Similar results were observed in a sensitivity analysis based on intent-to-treat principles: adjusted mean ± s.e. changes in HbA1c of -2.7 ± 0.1% and -1.8 ± 0.1%, respectively; treatment difference of -0.9% (95% CI -1.3 to -0.6; p <0.0001). A treatment response of HbA1c <7.0% was achieved by 61 and 40% of patients in the linagliptin/metformin and linagliptin groups, respectively. Few patients experienced drug-related adverse events (8.8 and 5.7% of patients in the linagliptin/metformin and linagliptin groups, respectively). Hypoglycaemia occurred in 1.9 and 3.2% of patients in the linagliptin/metformin and linagliptin groups, respectively (no severe episodes). Body weight decreased significantly with the combination therapy (-1.3 kg between-group difference; p =0.0033).

CONCLUSIONS

Linagliptin in initial combination with metformin in patients with newly diagnosed type 2 diabetes and marked hyperglycaemia, an understudied group, elicited significant improvements in glycaemic control with a low incidence of hypoglycaemia, weight gain or other adverse effects. These results support early combination treatment strategies and suggest that newly diagnosed patients with marked hyperglycaemia may be effectively managed with oral, non-insulin therapy.

Cardiorenal metabolic syndrome and cardiometabolic risks in minority populations

Cardiovascular disease (CVD), including heart disease and stroke, is the leading cause of death in the USA, regardless of self-determined race/ethnicity, and largely driven by cardiometabolic risk (CMR) and cardiorenal metabolic syndrome (CRS). The primary drivers of increased CMR include obesity, hypertension, insulin resistance, hyperglycemia, dyslipidemia, chronic kidney disease as well as associated adverse behaviors of physical inactivity, smoking, and unhealthy eating habits. Given the importance of CRS for public health, multiple stakeholders, including the National Minority Quality Forum (the Forum), the American Association of Clinical Endocrinologists (AACE), the American College of Cardiology (ACC), and the Association of Black Cardiologists (ABC), have developed this review to inform clinicians and other health professionals of the unique aspects of CMR in racial/ethnic minorities and of potential means to improve CMR factor control, to reduce CRS and CVD in diverse populations, and to provide more effective, coordinated care. This paper highlights CRS and CMR as sources of significant morbidity and mortality (particularly in racial/ethnic minorities), associated health-care costs, and an evolving index tool for cardiometabolic disease to determine geographical and environmental factors. Finally, this work provides a few examples of interventions potentially successful at reducing disparities in cardiometabolic health.

Bodily Aesthetic Ideals Among Latinas With Type 2 Diabetes

Purpose

The purpose of this study was to examine how attitudes and practices related to bodily aesthetic ideals and self-care might inform the engagement of Latinas with type 2 diabetes (T2DM).

Methods

Focus groups were used to collect qualitative data concerning bodily aesthetic ideals and diabetes management, including help-seeking experiences, from Latina women with T2DM (n = 29) receiving care through Latino Diabetes Initiative at the Joslin Diabetes Center. Focus groups were conducted in Spanish, audiotaped, transcribed, and content analyzed.

Results

Four main themes emerged: (1) a preference among participants for a larger than average body size, although perceptions of attractiveness were more closely linked to grooming than body size; bodily dissatisfaction centered on diabetes-induced skin changes, virilization, and fatigue rather than weight; (2) diabetic complications, especially foot pain, as a major obstacle to exercise; (3) fatalistic attitudes regarding the inevitability of diabetes and reversal of its complications; and (4) social burdens, isolation, and financial stressors as contributing to disease exacerbation.

Conclusions

Interventions that emphasize reduced body size may be less effective with Latinas who have T2DM than those that emphasize the benefits of exercise and weight loss for skin health, energy levels, and reduced virilization.

Previously unrecognized trends in diabetes consumption clusters in medicare

OBJECTIVE

To examine the annual cost profiles of Medicare beneficiaries with diabetes to identify patterns in their consumption of benefits.

METHODS

Retrospective expenditure data were collected from Medicare records. Beneficiaries with diabetes were grouped into 5 consumption clusters ranging from "crisis consumers" at the high end to "low consumers" at the low end.

RESULTS

The percentages of beneficiaries and expenditures for the consumption clusters remained generally constant from year to year. As expected, most of Medicare's budget each year was spent on crisis, heavy, and moderate consumers. However, a notable proportion of low and light consumers from one year go on to become crisis and heavy consumers in subsequent years. A review of total 2001 through 2006 inpatient costs for the year 2000 clusters revealed that 47% of these costs were for year 2000 low and light consumers and only 27% were for year 2000 crisis and heavy consumers.

CONCLUSIONS

This analysis revealed previously unrecognized trends, whereby a notable proportion of low and light consumers during one year went on to become crisis and heavy consumers in subsequent years, representing a large proportion of inpatient costs. These findings have important implications for disease management programs, which typically focus intervention efforts exclusively on crisis and heavy consumers.

Do older adults aged 60-75 years benefit from diabetes behavioral interventions?

OBJECTIVE

In this secondary analysis, we examined whether older adults with diabetes (aged 60-75 years) could benefit from self-management interventions compared with younger adults. Seventy-one community-dwelling older adults and 151 younger adults were randomized to attend a structured behavioral group, an attention control group, or one-to-one education.

RESEARCH DESIGN AND METHODS

We measured A1C, self-care (3-day pedometer readings, blood glucose checks, and frequency of self-care), and psychosocial factors (quality of life, diabetes distress, frustration with self-care, depression, self-efficacy, and coping styles) at baseline and 3, 6, and 12 months postintervention.

RESULTS

Both older (age 67 ± 5 years, A1C 8.7 ± 0.8%, duration 20 ± 12 years, 30% type 1 diabetes, 83% white, 41% female) and younger (age 47 ± 9 years, A1C 9.2 ± 1.2%, 18 ± 12 years with diabetes, 59% type 1 diabetes, 82% white, 55% female) adults had improved A1C equally over time. Importantly, older and younger adults in the group conditions improved more and maintained improvements at 12 months (older structured behavioral group change in A1C -0.72 ± 1.4%, older control group -0.65 ± 0.9%, younger behavioral group -0.55 ± 1.2%, younger control group -0.43 ± 1.7%). Furthermore, frequency of self-care, glucose checks, depressive symptoms, quality of life, distress, frustration with self-care, self-efficacy, and emotional coping improved in older and younger participants at follow-up.

CONCLUSIONS

The findings suggest that, compared with younger adults, older adults receive equal glycemic benefit from participating in self-management interventions. Moreover, older adults showed the greatest glycemic improvement in the two group conditions. Clinicians can safely recommend group diabetes interventions to community-dwelling older adults with poor glycemic control.

Food purchasing selection among low-income, Spanish-speaking Latinos

BACKGROUND

In the U.S., poverty has been linked to both obesity and disease burden. Latinos in the U.S. are disproportionately affected by poverty, and over the past 10 years, the percentage of overweight U.S. Latino youth has approximately doubled. Buying low-cost food that is calorie-dense and filling has been linked to obesity. Low-income individuals tend to favor energy-dense foods because of their low cost, and economic decisions made during food purchasing have physiologic repercussions. Diets based on energy-dense foods tend to be high in processed staples, such as refined grains, added sugars, and added fats. These diets have been linked to a higher risk of obesity, type 2 diabetes, and cardiovascular disease.

PURPOSE

This pilot study conducted ethnographic qualitative analyses combined with quantitative analyses to understand grocery shopping practices among 20 Spanish-speaking, low-income Latino families. The purpose was to analyze food selection practices in order to determine the effect of nutrition education on changes in shopping practices to later develop educational tools to promote selection of healthier food options.

METHODS

Participants received tailored, interactive, nutrition education during three to five home visits and a supermarket tour. Grocery store receipts for grocery purchases collected at baseline and at the end of the project were analyzed for each family to extract nutritional content of purchased foods. Nutritional content was measured with these factors in mind: quantity, calories, fats, carbohydrates, fiber, protein, and percentage of sugary beverages and processed food. Data were collected in 2010-2011 and analyzed in 2011-2012.

RESULTS

After receiving between three and five home-based nutrition education sessions and a supermarket tour over a 6-month period, many families adopted instructions on buying budget-friendly, healthier alternative foods. Findings indicate that participating families decreased the total number of calories and calories per dollar purchased from baseline to post-education (median total calories: baseline, 20,191; post-education, 15,991, p=0.008); median calories per dollar: baseline, 404; post-education, 320, p=0.008). The median grams of carbohydrates per dollar (baseline, 66, post-education, 45) and median calories from processed food (baseline, 11,000, post-education, 7845) were not reduced (p=0.06).

CONCLUSIONS

This pilot study demonstrated that grocery shopping practices are an important factor to address in nutrition education among Spanish-speaking, low-income individuals, and that there may be ways to encourage low-income, Latino families to purchase healthier foods. Findings challenged arguments suggesting that such an approach is not possible because of the high cost of healthier foods.

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.

The effect of a structured behavioral intervention on poorly controlled diabetes: a randomized controlled trial

BACKGROUND

Although maintaining nearly normal glycemia delays onset and slows progression of diabetes complications, many patients with diabetes and their physicians struggle to achieve glycemic targets. The best methods to support patients as they follow diabetes prescriptions and recommendations are unclear.

METHODS

To test the efficacy of a behavioral diabetes intervention in improving glycemia in long-duration, poorly controlled diabetes, we randomized 222 adults with diabetes (49% type 1) (mean [SD] age, 53 [12] years; mean [SD] disease duration 18 [12] years; mean [SD] hemoglobin A(1c) [HbA(1c)] concentration, 9.0% [1.1%]) to attend (1) a 5-session manual-based, educator-led structured group intervention with cognitive behavioral strategies (structured behavioral arm); (2) an educator-led attention control group education program (group attention control); or (3) unlimited individual nurse and dietitian education sessions for 6 months (individual control). Outcomes were baseline and 3-, 6-, and 12-month postintervention HbA(1c) levels (primary) and frequency of diabetes self-care, 3-day pedometer readings, 24-hour diet recalls, average number of glucose checks, physical fitness, depression, coping style, self-efficacy, and quality of life (secondary).

RESULTS

Linear mixed modeling found that all groups showed improved HbA(1c) levels (P < .001). However, the structured behavioral arm showed greater improvements than the group and individual control arms (3-month HbA(1c) concentration changes: -0.8% vs -0.4% and -0.4%, respectively (P = .04 for group × time interaction). Furthermore, participants with type 2 disease showed greater improvement than those with type 1 (P = .04 for type of diabetes × time interaction). Quality of life, glucose monitoring, and frequency of diabetes self-care did not differ by intervention over time.

CONCLUSIONS

A structured, cognitive behavioral program is more effective than 2 control interventions in improving glycemia in adults with long-duration diabetes. Educators can successfully use modified psychological and behavioral strategies.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT000142922.

Understanding the Hispanic/Latino patient

The Hispanic/Latino population is the largest minority group in the United States, representing approximately 16% of the population in 2010. The US Census Bureau defines Hispanic/Latino origin as ethnicity, which tends to be associated with culture and is distinct from race. Based on the US Census Bureau classifications, Hispanics/Latinos have at least 3 main racial backgrounds (white, black, and Native Indian), with the combination and proportion differing among Hispanic/Latino subgroups. The reflection of these racial differences in genetic ancestry partly explains why biological characteristics differ among Hispanic/Latino subgroups. Partly as a result of variations in biological characteristics, the risk of type 2 diabetes mellitus varies among Hispanic/Latino subgroups. According to data from the 1982 to 1984 Hispanic Health and Nutrition Examination Survey (HHANES), the prevalence of diagnosed and undiagnosed type 2 diabetes among adults aged 45 to 74 years was higher in Mexican Americans (23.9%) and Puerto Ricans (26.1%) compared with Cubans (15.8%). In addition to genetics, there are multiple social and cultural factors that affect the prevalence and course of type 2 diabetes in Hispanic/Latino individuals. Although certain aspects of Hispanic/Latino culture may become barriers in the management of type 2 diabetes in this population, these cultural characteristics may also represent an opportunity for prevention and/or improvement of care. It is important for healthcare providers to have an understanding and appreciation of Hispanic/Latino culture in order to provide their Hispanic/Latino patients with healthcare that is culturally and socially appropriate. Only by considering genetic, social, and cultural factors can type 2 diabetes be successfully prevented, treated, and managed in Hispanic/Latino patients.

Long-term benefits of insulin therapy and glycemic control in overweight and obese adults with type 2 diabetes

PROBLEM

Obesity and type 2 diabetes have reached epidemic proportions in the United States. Obese patients are at especially high risk for the development of metabolic syndrome, a clustering of metabolic abnormalities associated with insulin resistance that usually precede the development of cardiovascular disease. Overweight or obesity, along with insulin resistance, is frequently present in people with type 2 diabetes.

METHODS

A literature search of the PubMed and MEDLINE databases, using the terms diabetes, obesity, metabolic syndrome, glycemic control, antidiabetic therapy, and insulin, was performed. Articles published between 1985 and 2006 that examined diabetes management in the obese population were selected and reviewed.

RESULTS

There is new evidence suggesting that tight glycemic control and earlier initiation of insulin therapy can improve outcomes in obese patients with type 2 diabetes, thereby reducing the risk for the development of both macrovascular and microvascular complications of the disease. Insulin also appears to exhibit anti-inflammatory effects, which may provide additional protection against the development of atherosclerosis. Despite the benefits of insulin therapy, many patients and physicians remain reluctant to start insulin due to concerns about weight gain.

CONCLUSION

Newer insulin formulations can effectively improve glycemic control without significant effects on patient weight and, therefore, may be particularly useful in patients who are overweight or obese. Implementation of comprehensive treatment regimens that emphasize dietary modification, physical activity, and exercise, and aggressive use of pharmacological agents to achieve tight glycemic control through physiological regimens offer the most promise for reducing long-term complications in obese patients with type 2 diabetes.

Overweight Latino children and adolescents have marked endothelial dysfunction and subclinical vascular inflammation in association with excess body fat and insulin resistance

OBJECTIVE

We measured plasma markers of endothelial dysfunction, vascular inflammation, and pro-coagulation in obese Hispanic/Latino children and adolescents with normal glucose tolerance and determined their relationship to body composition and indexes of glucose and lipid metabolism.

RESEARCH DESIGN AND METHODS

A total of 38 lean or obese Hispanic children and adolescents (10-18 years of age) were selected. The overweight group (n = 21) had a BMI >85th percentile for their age and sex, and the lean group (n = 17) had a BMI between the 25th and 50th percentiles. Studies included an oral glucose tolerance test, measurements of plasma glucose and lipids, several markers of endothelial function and inflammation, and determination of body composition by dual X-ray absorptiometry.

RESULTS

The obese group had higher systolic blood pressure and plasma triglycerides and was more insulin resistant than the lean group. The obese group also had higher plasma soluble intercellular adhesion molecule (259.5 +/- 60.0 vs. 223.2 +/- 47.5 ng/ml, P = 0.047), tumor necrosis factor-alpha (2.57 +/- 1.1 vs. 1.74 +/- 0.6 pg/ml, P = 0.008), high-sensitivity C-reactive protein (2.0 vs. 0.13 mg/l, P < 0.0001), plasminogen-activated inhibitor-1 (47.0 +/- 35.7 vs. 12.0 +/- 5.2 ng/ml, P < 0.0001), tissue plasminogen activator (6.1 +/- 1.9 vs. 4.1 +/- 0.8 ng/ml, P = 0.001), and white blood cell count (6.9 vs. 5.3 x 10(3), P = 0.031) and lower levels of adiponectin (8.7 +/- 3.3 vs. 12.6 +/- 5.2 microg/ml, P = 0.022). No significant differences were observed for soluble vascular cell adhesion molecule or interleukin-6.

CONCLUSIONS

Overweight Hispanic children and adolescents with normal glucose tolerance exhibit increased plasma markers of endothelial dysfunction and subclinical inflammation in association with obesity and insulin resistance. These abnormalities may predispose them to the development of type 2 diabetes and cardiovascular disease.

Cultural approaches to diabetes self-management programs for the Latino community

The issue of diabetes within the Latino population of the United States is of such magnitude that reviewing previously published studies on culturally oriented diabetes self-management interventions is imperative to further understanding and progress on this matter. The purpose of this revision is to illustrate what has been accomplished to date, analyze the lessons learned, and restate the importance of developing culturally relevant interventions for vulnerable populations.

Type 2 diabetes in the Hispanic or Latino population: challenges and opportunities

PURPOSE OF REVIEW

To describe how type 2 diabetes affects the Latino or Hispanic population in the United States, and identify the multiple challenges and opportunities to improve diabetes care in this rapidly growing group.

RECENT FINDINGS

Three compelling reasons justify the work in this area. First, this group has become the largest minority in the country, representing 13.7% of the total population. Based on current growth rates, one in four individuals will be of Hispanic origin by the year 2050. Second, this population suffers from very high rates of type 2 diabetes, obesity, the metabolic syndrome and their multiple vascular complications. A genetic tendency to develop insulin resistance and abdominal obesity, along with multiple nutritional, lifestyle, socio-economic and cultural factors, influence the development and course of type 2 diabetes among Latinos. Third, Hispanics have lagged behind in their diabetes care when compared with the predominant non-Hispanic White population.

SUMMARY

Understanding the challenges and opportunities in Latinos with diabetes is necessary to develop and implement comprehensive culturally oriented diabetes care, education, outreach and research programs. Some of these strategies may also be beneficial for other groups and can contribute to better integrate our societies.

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.

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.

Diabetes in the Hispanic or Latino population: genes, environment, culture, and more

The Hispanic or Latino population is the largest minority group in the United States, currently representing 13.7% of the total U.S. population. Hispanics or Latinos usually suffer from higher rates of type 2 diabetes, obesity, metabolic syndrome, and their multiple vascular complications. Inadequate nutrition and reduced physical activity in the setting of an increased genetic predisposition to type 2 diabetes have contributed to the inexorable rise in metabolic abnormalities in Hispanics in the United States, which now affect many children and adolescents. It is evident that multiple medical, cultural, and socioeconomic factors influence the development of diabetes, its course, and its consequences. Our health care system is barely prepared to face the challenge of managing diabetes in this high-risk group. Culturally oriented clinical care, education, outreach and research programs are needed to better identify the challenges to create opportunities to improve the lives of Hispanics or Latinos with diabetes or at risk for the disease.

Psychosocial factors associated with poor diabetes self-care management in a specialized center in Mexico City

To examine the relationship between demographic, clinical and psychosocial variables and diabetes self-care management in Mexican type 2 diabetic patients. Cross-sectional study of 176 consecutive patients with type 2 diabetes aged 30-75 years, attending a tertiary health-care center in Mexico City. A brief medical history and previously validated questionnaires were completed. The study group consisted of 64 males/112 females, aged 55 +/- 11 years, mean diabetes duration of 12 +/- 8 years and HbA1c of 9.0 +/- 2.0%, 78.4% reported following the correct dose of diabetes pills or insulin, 58% ate the recommended food portions, and 44.3% did exercise three or more times per week. A good adherence to these three recommendations was observed in only 26.1% of the patients. These patients considered as a group were characterized by a greater knowledge about the disease (P < 0.00001), regular home blood glucose monitoring (P < 0.01), an inner perception of better diabetes control (P = 0.007), good health (P = 0.004) and better communication with their physician (P < 0.02). A poor adherence to two or the three main diabetes care recommendations was associated with a depressive state (OR 2.38, 95% CI 1.1-4.9, P < 0.01) and a history of excessive alcohol intake (OR 4.03, 95% CI 1.1-21.0, P = 0.03). Poor adherence to standard diabetes care recommendations is frequently observed in patients with type 2 diabetes attending a specialized health care center in Mexico City. Depression must be identified and treated effectively.

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.

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.

Endothelial dysfunction, inflammation, and insulin resistance: a focus on subjects at risk for type 2 diabetes

Subjects with obesity, family history of type 2 diabetes, polycystic ovary syndrome, previous gestational diabetes, dyslipidemia, hypertension, impaired glucose tolerance or impaired fasting glucose, and those with metabolic syndrome are at risk for the development of type 2 diabetes. Some of them are also at risk for cardiovascular disease. Some underlying abnormalities such as insulin resistance, endothelial dysfunction, and low-grade chronic inflammation are frequently present and closely associated in all these groups. The flow of substrates, hormones, and cytokines from visceral fat to skeletal muscle and to the endothelial cells, along with some genetic abnormalities that lead to impaired insulin action in the peripheral tissues and to impaired insulin-stimulated nitric oxide production in endothelial cells, may play a role in establishing these shared metabolic and vascular derangements. Weight loss, thiazolidinediones, and metformin improve vascular function in subjects at risk for type 2 diabetes and may prove to reduce cardiovascular events in these individuals.

Endothelial dysfunction in obesity and insulin resistance: a road to diabetes and heart disease

Obesity, insulin resistance, and endothelial dysfunction closely coexist throughout the natural history of type 2 diabetes. They all can be identified not only in people with type 2 diabetes, but also in various groups at risk for the disease, such as individuals with impaired glucose tolerance, family history of type 2 diabetes, hypertension, dyslipidemia, prior gestational diabetes, or polycystic ovary syndrome. Whereas their evident association cannot fully establish a cause-effect relationship, fascinating mechanisms that bring them closer together than ever before are rapidly emerging. Central or abdominal obesity leads to insulin resistance and endothelial dysfunction through fat-derived metabolic products, hormones, and cytokines. Insulin resistance leads to endothelial dysfunction through the frequent association with traditional cardiovascular risk factors and through some more direct novel mechanisms. Some specific and shared insulin signaling abnormalities in muscle, fat, and endothelial cells, as well as some new genetic and nontraditional factors, may contribute to this interesting association. Some recent clinical studies demonstrate that nonpharmacological and pharmacological strategies targeting obesity and/or insulin resistance ameliorate endothelial function and low-grade inflammation. All these findings have added a new dimension to the association of obesity, insulin resistance, and endothelial dysfunction that may become a key target in the prevention 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.

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.

The effect of hormonal replacement therapy on the vascular reactivity and endothelial function of healthy individuals and individuals with type 2 diabetes

Estrogens protect healthy women from cardiovascular disease. However, epidemiological data suggest that women with diabetes are denied the cardioprotection associated with estrogens. Whether or not hormonal replacement therapy (HRT) confers cardiovascular benefits in postmenopausal women with diabetes is not known. The aim of this study was to examine the effects of HRT on the microvascular reactivity and endothelial function of individuals with and without diabetes. We studied the following groups of individuals: premenopausal healthy women [n = 28, age 41 +/- 8 yr (mean +/- SD)], premenopausal women with type 2 diabetes (n = 16, age 43 +/- 6 yr); postmenopausal healthy women (n = 12, age 57 +/- 4 yr), postmenopausal women with diabetes (n = 17, age 62 +/- 5 yr); postmenopausal healthy women on HRT (n = 13, age 51 +/- 5 yr), postmenopausal women with diabetes on HRT (n = 11, age 57 +/- 7 yr). We used laser Doppler flowmetry to measure forearm cutaneous vasodilatation in response to iontophoresis of 1% acetylcholine (endothelium dependent) and 1% sodium nitroprusside (endothelium independent). The endothelium-dependent vasodilation was significantly higher in premenopausal healthy women (180 +/- 67%; increase over baseline) compared to premenopausal diabetic women (87 +/- 41%; P < 0.001). endothelium-dependent vasodilation was also higher in postmenopausal healthy women on HRT (143 +/- 52) compared with postmenopausal diabetic women on HRT (86 +/- 61), postmenopausal healthy women without HRT (104 +/- 43), and postmenopausal diabetic women without HRT (74 +/- 28; P < 0.001). A similar pattern of responses was observed in the endothelium-independent vasodilation (premenopausal healthy women, 126 +/- 56; premenopausal diabetic women, 88 +/- 26; postmenopausal healthy women on HRT, 121 +/- 37; postmenopausal diabetic women on HRT, 88 +/- 41; postmenopausal healthy women without HRT, 84 +/- 36; and postmenopausal diabetic women without HRT, 73 +/- 36; P < 0.001). Soluble intercellular adhesion molecule (sICAM) was also measured among all the women with diabetes. Premenopausal women with diabetes (248.9 +/- 56 ng/ml) and postmenopausal women with diabetes on HRT (257.7 +/- 49 ng/ml) had lower sICAM levels compared with the postmenopausal diabetic women without HRT (346.4 +/- 149 ng/ml; P < 0.05). We conclude that menopausal status and type 2 diabetes are associated with impaired microvascular reactivity. HRT substantially improves microvascular reactivity in postmenopausal healthy women. In contrast, the effect of HRT on the microvascular reactivity of postmenopausal diabetic women is less apparent. However, the use of HRT among women with diabetes is associated with lower sICAM levels, suggesting an attenuation in endothelial activation.

Soluble intercellular adhesion molecule, vascular cell adhesion molecule, and impaired microvascular reactivity are early markers of vasculopathy in type 2 diabetic individuals without microalbuminuria

OBJECTIVE

Using von Willebrand Factor (vWF) as a marker of endothelial function, previous studies have shown that the development of microalbuminuria is associated with the onset of endothelial dysfunction in individuals with type 2 diabetes. We tested the hypothesis that endothelial dysfunction is already evident in normoalbuminuric individuals with type 2 diabetes.

RESEARCH DESIGN AND METHODS

We used laser Doppler imaging scanning to measure vasodilation in the forearm skin in response to iontophoresis of 1% acetylcholine (endothelium-dependent) and 1% sodium nitroprusside (endothelium-independent). Multiple indicators of endothelial function--soluble intercellular adhesion molecule (sICAM), soluble vascular cell adhesion molecule (sVCAM), vWF, and microvascular reactivity--were measured in 20 healthy control subjects, 45 normoalbuminuric (urinary albumin/creatinine ratio < 30 micrograms/mg) individuals with type 2 diabetes, and 14 microalbuminuric (urinary albumin/creatinine ratio between 30 and 300 micrograms/mg) individuals with type 2 diabetes.

RESULTS

Serum sICAM and sVCAM levels were elevated in the normoalbuminuric (305 +/- 120, 851 +/- 284 ng/ml) and microalbuminuric (300 +/- 89, 845 +/- 252 ng/ml) individuals with diabetes when compared with the healthy control subjects (213 +/- 58, 661 +/- 176 ng/ml) (P < 0.01). Furthermore, the microvascular endothelium-dependent and -independent vasodilation was reduced in the normoalbuminuric (76 +/- 44, 70 +/- 33) (percent increase in perfusion over baseline) and microalbuminuric (74 +/- 41, 73 +/- 28) individuals with diabetes compared with healthy control subjects (126 +/- 67, 120 +/- 47) (P < 0.05). In contrast, plasma vWF was elevated only in the microalbuminuric individuals with diabetes (129 +/- 35%) compared with the normoalbuminuric individuals with diabetes (110 +/- 34) and healthy control subjects (111.3 +/- 39) (P < 0.05). On stepwise multivariate analysis, fasting blood glucose was the most important contributing factor to the variation in microvascular reactivity and sVCAM, whereas insulin resistance (by homeostasis model assessment) was the most important contributing factor to the variation in sICAM. Addition of all clinical and biochemical measures explained only 15-22% of the variation in sICAM, sVCAM, and microvascular reactivity.

CONCLUSIONS

Multiple markers of endothelial dysfunction were evident in normoalbuminuric individuals with type 2 diabetes. The pathogenic process of vasculopathy in type 2 diabetes occurs early and may be operative before the development of microalbuminuria.

Microvascular and macrovascular reactivity is reduced in subjects at risk for type 2 diabetes

Abnormalities in vascular reactivity in the micro- and macrocirculation are well established in type 2 diabetes. However, little is known about changes in vascular reactivity in those at risk for developing type 2 diabetes. To address this situation, the vascular reactivity in both the micro- and macrocirculation was studied in four age and sex comparable groups: 30 healthy normoglycemic subjects with no history of type 2 diabetes in a first-degree relative (controls), 39 healthy normoglycemic subjects with a history of type 2 diabetes in one or both parents (relatives), 32 subjects with impaired glucose tolerance (IGT), and 42 patients with type 2 diabetes without vascular complications (diabetes). Laser Doppler perfusion imaging was used to measure vasodilation in the forearm skin in response to iontophoresis of 1% acetylcholine chloride (Ach) (endothelium-dependent) and 1% sodium nitroprusside (SNP) (endothelium-independent), whereas high-resolution ultrasound images were used to measure brachial artery diameter changes during reactive hyperemia. Plasma concentrations of endothelin-1 (ET-1), 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 vasodilatory responses to Ach, expressed as percent increase of blood flow over baseline, were reduced in relatives (98 +/- 48, mean +/- SD), IGT (94 +/- 52), and diabetes (74 +/- 45) compared with controls (126 +/- 67) (P < 0.001 controls versus relatives, IGT, and diabetes). The responses to SNP were similarly reduced: controls (123 +/- 46), relatives (85 +/- 46), IGT (83 +/- 48), and diabetes (65 +/- 31) (P < 0.001 controls versus relatives, IGT, and diabetes) as were the responses in the brachial artery diameter during reactive hyperemia: controls (13.7 +/- 6.1), relatives (10.5 +/- 6.7), IGT (9.8 +/- 4.5), and diabetes (8.4 +/- 5.0) (P < 0.01 controls versus relatives, IGT, and diabetes). Women had greater responses than men in both the micro- and macrovascular circulatory tests, but a similar progressive reduction was observed in both sexes with increasing degrees of glucose intolerance. A significant inverse correlation was found between microvascular reactivity and systolic blood pressure, fasting plasma glucose, HDL cholesterol, fasting plasma insulin, and homeostasis model assessment (HOMA) values, an index of insulin resistance. BMI and diastolic blood pressure had a significant inverse correlation only with endothelium-dependent vasodilation. In the macrocirculation, systolic blood pressure, HbA1c, HDL cholesterol, and HOMA had significant correlation with brachial artery diameter changes. Compared with control subjects, ET-1 was significantly higher in all groups, vWF was higher only in the diabetic group, sICAM levels were higher in the IGT and diabetic groups, while sVCAM concentrations were higher in the relatives and those with diabetes (P < 0.05). On stepwise multivariate analysis, age, sex, fasting plasma glucose, and BMI were the most important contributing factors to the variation of vascular reactivity. Addition of all clinical and biochemical measures explained only 32-37% of the variation in vascular reactivity. These results suggest that abnormalities in vascular reactivity and biochemical markers of endothelial cell activation are present early in individuals at risk of developing type 2 diabetes, even at a stage when normal glucose tolerance exists, and that factors in addition to insulin resistance may be operative.

Reactive hyperemic response of the brachial artery: comparison of proximal and distal occlusion

RATIONALE AND OBJECTIVES

The authors compared the postocclusion hyperemic responses of the brachial artery after occluding blood flow proximal to and distal to the studied area.

MATERIALS AND METHODS

Response of the brachial artery to hypoxia was evaluated with duplex Doppler ultrasound in 13 healthy subjects. A pneumatic tourniquet was first positioned 2-5 cm superior to the left elbow, proximal to the area of artery studied. Two hours later the response was remeasured with the tourniquet positioned 2-5 cm inferior to the elbow, distal to the artery studied. Arterial diameter, mean and peak flow velocities, and heart rate were assessed.

RESULTS

No significant differences were observed between measurements of baseline and postischemic arterial diameter, percentage diameter change, baseline mean arterial blood flow velocity, baseline peak arterial blood flow velocity, or postischemic heart rate obtained with proximal occlusion of the artery and those obtained with distal occlusion. In contrast, mean and peak postischemic arterial blood flow velocity and preocclusion heart rate were higher in measurements made during proximal artery occlusion. Significant correlation was found between measurements of percentage change in artery diameter obtained with proximal artery occlusion and those obtained with distal occlusion (r = 0.611, P < .05).

CONCLUSION

There are no major differences in postischemic changes in brachial artery diameter related to reactive hyperemia between blood flow occlusion applied proximal and distal to the studied area. However, there are significant differences in the mean and peak systolic velocities. Either occlusion site can be used for clinical studies if arterial diameter change is monitored, but if velocity measurements are being compared, a single occlusion site should be chosen.