Racial Differences in the Relationship of Glucose Concentrations and Hemoglobin A1c Levels.

Background: Debate exists as to whether the higher hemoglobin A1c (HbA1c) levels observed in black persons than in white persons are due to worse glycemic control or racial differences in the glycation of hemoglobin. Objective: To determine whether a racial difference exists in the relationship of mean glucose and HbA1c. Design: Prospective, 12-week observational study. Setting: 10 diabetes centers in the United States. Participants: 104 black persons and 104 white persons aged 8 years or older who had had type 1 diabetes for at least 2 years and had an HbA1c level of 6.0% to 12.0%. Measurements: Mean glucose concentration, measured by using continuous glucose monitoring and compared by race with HbA1c, glycated albumin, and fructosamine values. Results: The mean HbA1c level was 9.1% in black persons and 8.3% in white persons. For a given HbA1c level, the mean glucose concentration was significantly lower in black persons than in white persons (P = 0.013), which was reflected in mean HbA1c values in black persons being 0.4 percentage points (95% CI, 0.2 to 0.6 percentage points) higher than those in white persons for a given mean glucose concentration. In contrast, no significant racial differences were found in the relationship of glycated albumin and fructosamine levels with the mean glucose concentration (P > 0.20 for both comparisons). Limitation: There were too few participants with HbA1c levels less than 6.5% to generalize the results to such individuals. Conclusion: On average, HbA1c levels overestimate the mean glucose concentration in black persons compared with white persons, possibly owing to racial differences in the glycation of hemoglobin. However, because race only partially explains the observed HbA1c differences between black persons and white persons, future research should focus on identifying and modifying barriers impeding improved glycemic control in black persons with diabetes. Primary Funding Source: Helmsley Charitable Trust.

Hypoglycemia in Older Adults with Type 1 Diabetes.

BACKGROUND: Hypoglycemia is a major concern in older adults with type 1 diabetes (T1D) and there is limited knowledge in this population. We examined data from 199 adults, ≥60 years of age, who participated in a T1D Exchange study assessing factors associated with severe hypoglycemia (SH) in older adults with T1D: 100 with SH in the prior year and 99 with no SH in prior 3 years (mean age 68; mean diabetes duration 40 years; 47% female; 92% non-Hispanic white). Hypoglycemia was assessed with up to 14 days of blinded continuous glucose monitoring (CGM). Linear regression models were performed to assess the association between biochemical hypoglycemia [defined as percentage of time below specific cutoffs (<70/60/50 mg/dL)] and various factors. RESULTS: Overall, participants had CGM values <70 mg/dL for a median of 91 min per day. On 53% of days, glucose levels continuously were <70 mg/dL for ≥20 min. Hypoglycemia was found to be strongly associated with glucose variability (r = 0.76; P < 0.001). Time spent in hypoglycemia was greater in those who were younger (P = 0.004), had shorter diabetes duration (P = 0.008), lower HbA1c (P < 0.001), and undetectable C-peptide (P = 0.001), but did not differ by insulin method, education level, number of blood glucose checks per day, cognition, activities of daily living, or fear of hypoglycemia. INNOVATION: This study adds valuable data on the frequency of hypoglycemia in older adults with T1D. CONCLUSION: Future studies need to focus on how to prevent hypoglycemia in this vulnerable population of older adults with long-standing T1D.

Lifestyle modification for metabolic syndrome: a systematic review.

BACKGROUND: All 5 components of metabolic syndrome have been shown to improve with lifestyle and diet modification. New strategies for achieving adherence to meaningful lifestyle change are needed to optimize atherosclerotic cardiovascular risk reduction. We performed a systematic literature review, based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses framework (PRISMA), investigating optimal methods for achieving lifestyle change in metabolic syndrome. METHODS: We submitted standardized search terms to the PubMed Central, CINAHL, Web of Science, and Ovid databases. Within those results, we selected randomized controlled trials (RCTs) presenting unique methods of achieving lifestyle change in patients with one or more components of the metabolic syndrome. Data extraction using the population, intervention, comparator, outcome, and risk of bias framework (PICO) was used to compare the following endpoints: prevalence of metabolic syndrome, prevalence of individual metabolic syndrome components, mean number of metabolic syndrome components, and amount of weight loss achieved. RESULTS: Twenty-eight RCTs (6372 patients) were included. Eight RCTs demonstrated improvement in metabolic syndrome risk factors after 1 year. Team-based, interactive approaches with high-frequency contact with patients who are motivated made the largest and most lasting impact. Technology was found to be a useful tool in achieving lifestyle change, but ineffective when compared with personal contact. CONCLUSION: Patient motivation leading to improved lifestyle adherence is a key factor in achieving reduction in metabolic syndrome components. These elements can be enhanced via frequent encounters with the health care system. Use of technologies such as mobile and Internet-based communication can increase the effectiveness of lifestyle change in metabolic syndrome, but should not replace personal contact as the cornerstone of therapy. Our ability to derive quantitative conclusions is limited by inconsistent outcome measures across studies, low power and homogeneity of individual studies, largely motivated study populations, short follow-up periods, loss to follow-up, and lack of or incomplete blinding.

Determinants of successful glycemic control among participants in the BARI 2D trial: a post-hoc analysis.

OBJECTIVE: The BARI 2D trial compared insulin provision (IP) versus insulin sensitization (IS) for the primary outcome of total mortality in participants with T2DM and cardiovascular disease (CVD). In this analysis we examine baseline characteristics that are associated with successful long-term glycemic control. RESEARCH DESIGN AND METHODS: In a 2×2 factorial design, 2368 participants were randomized to either IP or IS therapy, and to either prompt revascularization with medical therapy or medical therapy alone. Successful long-term glycemic control (success) was defined by simultaneously meeting 1) a mean HbA1c level of <7.0% after each participant's third year of follow-up period, and 2) adherence with medications only from the assigned glycemic treatment arm during >80% of the BARI 2D follow-up. The association between baseline variables and success was determined using unadjusted and adjusted logistic regression models. RESULTS: 1917 participants (962 IP and 955 IS participants) had sufficiently long follow-up and data for this analysis. Among these IP and IS participants, 235 and 335 participants met both criteria of success, respectively (p<0.001). Those not on insulin at entry had higher odds of success (OR 2.25; CI 1.79-2.82) when treated with IS versus IP medications, irrespective of baseline HbA1c levels. Younger age, shorter duration of T2DM, and lower HbA1c at baseline were also each independently associated with higher success when treated with IS versus IP medications. CONCLUSION: Patients similar to those in the BARI 2D trial may have a higher chance of achieving success with IS versus IP medications if they are younger, have shorter duration of T2DM, have lower HbA1c levels, have moderate or strenuous physically activity, and are not on insulin. In contrast, increasing age, longer duration of T2DM, higher HbA1c, and insulin therapy are associated with increased chance of success if treated with IP medications.

Differences in the management of type 1 diabetes among adults under excellent control compared with those under poor control in the T1D Exchange Clinic Registry.

OBJECTIVE: Optimizing glycemic control in type 1 diabetes is important to minimize the risk of complications. We used the large T1D Exchange clinic registry database to identify characteristics and diabetes management techniques in adults with type 1 diabetes, differentiating those under excellent glycemic control from those with poorer control. RESEARCH DESIGN AND METHODS: The cross-sectional analysis included 627 participants with HbA1c <6.5% (excellent control) and 1,267 with HbA1c ≥8.5% (fair/poor control) at enrollment who were ≥26 years of age (mean ± SD 45.9 ± 13.2 years), were not using continuous glucose monitoring, and had type 1 diabetes for ≥2 years (22.8 ± 13.0 years). RESULTS: Compared with the fair/poor control group, participants in the excellent control group had higher socioeconomic status, were more likely to be older and married, were less likely to be overweight, were more likely to exercise frequently, and had lower total daily insulin dose per kilogram (P < 0.0001 for each). Excellent control was associated with more frequent self-monitoring of blood glucose (SMBG), giving mealtime boluses before a meal rather than at the time of or after a meal, performing SMBG before giving a bolus, and missing an insulin dose less frequently (P < 0.0001 for each). Frequency of severe hypoglycemia was similar between groups, whereas diabetic ketoacidosis was more common in the fair/poor control group. CONCLUSIONS: Diabetes self-management related to insulin delivery, glucose monitoring, and lifestyle tends to differ among adults with type 1 diabetes under excellent control compared with those under poorer control. Future studies should focus on modifying diabetes management skills in adult type 1 diabetes patients with suboptimal glycemic control.

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

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

The impact of race/ethnicity on baseline characteristics and the burden of coronary atherosclerosis in the Bypass Angioplasty Revascularization Investigation 2 Diabetes trial.

OBJECTIVES: We aimed to test the impact of race/ethnicity on coronary artery disease (CAD) after adjusting for baseline risk factors. BACKGROUND: Whether race/ethnicity remains an important determinant of the burden of CAD even among patients with long-standing type 2 diabetes (diabetes mellitus) and established CAD is unknown. METHODS: Analysis of baseline data from the BARI 2D trial (January 1, 2001, to March 31, 2005) was performed. Myocardial jeopardy index (MJI) was evaluated by a blinded core angiographic laboratory. Multivariate regression analysis was performed to determine the independent association of race/ethnicity on the burden of CAD after adjusting for baseline risk factors. Data were collected from US and Canadian academic and community hospitals. The baseline analysis was performed on patients with long-standing diabetes and documented CAD with no prior revascularization at study entry (n = 1,331). The main outcome measure was MJI, which represents the percentage of myocardium jeopardized by significant lesions (≥50%). The secondary outcome measure was ≥2 lesions with ≥50% stenosis. RESULTS: Risk factors varied significantly among racial/ethnic groups. Blacks were significantly more likely to be women, have no health insurance, be current smokers, have higher body mass index, have hypertension, have a longer duration of diabetes, a higher hemoglobin A(1c) level, and were more likely to be taking insulin. Their mean total, low-density lipid, and high-density lipid cholesterol levels were higher, whereas their triglycerides were lower than others. After controlling for baseline risk factors, blacks had a significantly lower burden of CAD; the adjusted MJI was 5.43 U lower (95% CI -9.13 to -1.72), and the adjusted number of lesions was 0.53 fewer (95% CI -0.88 to -0.18) in blacks compared to whites. CONCLUSIONS: In the BARI 2D trial, self-reported race/ethnicity is associated with important differences in baseline risk factors and is a powerful predictor of the burden of CAD adjusting for such baseline differences. These findings may help direct medical intervention and resources and further investigation into the basis of racial/ethnic differences in CAD burden.

Health status after treatment for coronary artery disease and type 2 diabetes mellitus in the Bypass Angioplasty Revascularization Investigation 2 Diabetes trial.

BACKGROUND: Health status is a key outcome for comparing treatments, particularly when mortality does not differ significantly. METHODS AND RESULTS: Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) randomized 2368 patients with type 2 diabetes mellitus and stable ischemic heart disease to (1) prompt revascularization versus medical therapy and (2) insulin sensitization versus insulin provision. Randomization was stratified by the intended method of revascularization, coronary artery bypass graft surgery or percutaneous coronary intervention. The Duke Activity Status Index and RAND Energy, Health Distress, and Self-Rated Health scales were assessed at study entry and annually thereafter; linear mixed models were used to evaluate the effect of randomized treatment on these measures. Health status improved significantly from baseline to 1 year (P<0.001) in each randomized treatment group. Compared with medical therapy, prompt revascularization was associated with significantly greater improvements in Duke Activity Status Index (1.32 points; P<0.001), Energy (1.36 points; P=0.02), and Self-rated Health (1.77 points; P=0.007) but not Health Distress (-0.47; P=0.46). These treatment effects were largely maintained over 4 years of follow-up. The effect of revascularization on the Duke Activity Status Index was significantly larger in the subgroup of patients intended for coronary artery bypass graft surgery compared with the subgroup intended for percutaneous coronary intervention. Health status did not differ significantly on any of the 4 measures between the insulin provision and insulin sensitization strategies. CONCLUSIONS: Prompt coronary revascularization was associated with small yet statistically significant improvements in health status compared with initial medical therapy among patients with diabetes mellitus and stable ischemic heart disease. CLINICAL TRIAL REGISTRATION: http://www.clinicaltrials.gov. Unique identifier: NCT00006305.

Racial differences in the association between self-rated health status and objective clinical measures among participants in the BARI 2D trial.

OBJECTIVES: We explored whether and how race shapes perceived health status in patients with type 2 diabetes mellitus and coronary artery disease. METHODS: We analyzed self-rated health (fair or poor versus good, very good, or excellent) and associated clinical risk factors among 866 White and 333 Black participants in the Bypass Angioplasty Revascularization Investigation 2 Diabetes trial. RESULTS: Michigan Neuropathy Screening Instrument scores, regular exercise, and employment were associated with higher self-rated health (P < .05). Blacks were more likely than were Whites to rate their health as fair or poor (adjusted odds ratio [OR] = 1.88; 95% confidence interval [CI] = 1.38, 2.57; P < .001). Among Whites but not Blacks, a clinical history of myocardial infarction (OR = 1.61; 95% CI = 1.12, 2.31; P < .001) and insulin use (OR = 1.62; 95% CI = 1.10, 2.38; P = .01) was associated with a fair or poor rating. A post-high school education was related to poorer self-rated health among Blacks (OR = 1.86; 95% CI = 1.07, 3.24; P < .001). CONCLUSIONS: Symptomatic clinical factors played a proportionally larger role in self-assessment of health among Whites with diabetes and coronary artery disease than among Blacks with the same conditions.