Is race related to glycemic control? An assessment of glycosylated hemoglobin in two South Carolina communities

Glycaemic control for people with type 2 diabetes in Saudi Arabia - an urgent need for a review of management plan

BACKGROUND

The aim of this study was to assess inadequate glycaemic control and its associated factors among people with type 2 diabetes in Saudi Arabia.

METHODS

A cross-sectional study design was used. Adults with type 2 diabetes attending diabetes centres in Riyadh, Hofuf and Jeddah cities were interviewed and their anthropometrics were measured. Their medical records were also reviewed to collect information related to recent lab tests, medications, and documented comorbidities. Multivariable logistic regression were used for data analysis.

RESULTS

A total of 1111 participants were recruited in the study. Mean age was 57.6 (±11.1) years, 65.2% of the participants were females, and mean HbA1c was 8.5 ± 1.9%. About three-fourths of participants had inadequate glycaemic control (≥ 7%). Multivariable analysis showed that age ≤ 60 years, longer duration of diabetes, living in a remote location, low household income, low intake of fruits and vegetable, low level of physical activity, lack of knowledge about haemoglobin A1c, high waist-hip ratio, low adherence to medication, and using injectable medications were independent risk factors for inadequate glycaemic control.

CONCLUSIONS

Inadequate glycaemic control is prevalent among people with type 2 diabetes in Saudi Arabia. In order to improve glycaemic control diabetes management plan should aim at controlling the modifiable risk factors which include low intake of fruits and vegetable, low level of physical activity, lack of knowledge about haemoglobin A1c, high waist-hip ratio, and low adherence to medications.

Identifying Prediabetes and Type 2 Diabetes in Asymptomatic Youth: Should HbA1c Be Used as a Diagnostic Approach?

PURPOSE OF REVIEW

Because the incidence of type 2 diabetes and prediabetes in children is rising, routine screening of those at risk is recommended. In 2010, the ADA made the recommendation to include hemoglobin A1c (HbA1c) as a diagnostic test for diabetes, in addition to the oral glucose tolerance test or fasting plasma glucose. Our objective was to assess the pediatric literature with regard to HbA1c test performance and discuss advantages and disadvantages of use of the test for diagnostic purposes.

RECENT FINDINGS

HbA1c has a number of advantages, including elimination of the need for fasting, lower variability, assay standardization, and long-term association with future development of diabetes. It also has many drawbacks. It can be affected by a number of non-glycemic factors, including red blood cell turnover, hemoglobinopathies, medications, race, and age. In particular, it performs differently in children compared with adults, generally with lower sensitivity for prediabetes (as low as 0-5% in children vs 23-27% in adults) and lower area under the receiver operating characteristic curve (AUC) (0.53 vs 0.73 for prediabetes), and it has lower efficacy at a higher cost, compared with other tests of glycemia. Finally, HbA1c may perform very differently across diverse populations according to race/ethnicity; in Chinese populations, the proportion of individuals classified with prediabetes based on HbA1c predominates compared with IFG (77% for HbA1c vs 27.7% for IFG), whereas in US populations, it is the opposite (24.8% for HbA1c vs 80.1% for FPG). HbA1c is controversial because although it is convenient, it is not a true measure of glycemia. The interpretation of HbA1c results requires a nuanced understanding that many primary care physicians who are ordering the test in greater numbers do not possess. Alternative markers of glycemia may hold promise for the future but are not yet endorsed for use in practice. Further studies are needed to determine appropriate thresholds for screening tests and the long-term impact of screening and identification.

Regional, Geographic, and Ethnic Differences in Medication Adherence among Adults with Type 2 Diabetes

BACKGROUND:

Medication adherence, a critical component of glycemic control for patients with type 2 diabetes, differs by race/ethnicity. However, few studies have examined regional and rural/urban differences in medication adherence and whether racial/ethnic differences persist after controlling for these differences.

OBJECTIVE:

To examine regional, rural/urban, and racial/ethnic differences in medication adherence in a national sample of veterans with type 2 diabetes.

METHODS:

We performed a cohort study of a national sample of veterans with diabetes (N = 690,968) receiving prescriptions for insulin or oral hypoglycemic agents in 2002. Patients were followed until death, loss to follow-up, or through December 2006. We calculated the annual medication possession ratio (MPR) for each veteran across 4 groups of medication users: individuals using (1) insulin only, (2) oral hypoglycemic agents only, (3) insulin combined with hypoglycemic agents, and (4) insulin or oral hypoglycemic agents (primary analysis).

RESULTS:

In longitudinal models for the primary analysis, adjusting for relevant covariates and time trends, MPR was significantly lower among non-Hispanic blacks (NHBs), Hispanics, and individuals with other/missing/unknown race/ethnicity (6.07%, 1.76%, and 2.83% lower, respectively) relative to non-Hispanic whites (NHWs). MPR was also 2.0% higher in rural versus urban veterans and 1.28% higher in the mid-Atlantic, 2.04% higher in the Midwest, and 0.76% lower in the West, relative to the South. There was a significant race/ethnicity and urban/rural interaction. In NHWs and NHBs, MPR was 1.91 % and 2.00% higher, respectively, in rural versus urban veterans; in contrast, in Hispanics, MPR was 1.0% lower in rural veterans relative to urban veterans.

CONCLUSIONS:

In a national longitudinal cohort of veterans with type 2 diabetes, we found significant regional, rural/urban, and racial/ethnic differences in MPR. Rural/urban residence modified the effect of race/ethnicity on MPR. Recognition of these differences can enable clinicians to better allocate resources and target quality improvement programs.

Culturally Competent Diabetes Education

Purpose

The purpose of this study was to test effects of a culturally competent, dietary self-management intervention on physiological outcomes and dietary behaviors for African Americans with type 2 diabetes.

Methods

A longitudinal experimental study was conducted in rural South Carolina with a sample of 97 adult African Americans with type 2 diabetes who were randomly assigned to either usual care or the intervention. The intervention consisted of 4 weekly classes in low-fat dietary strategies, 5 monthly peer-professional group discussions, and weekly telephone follow-up. The culturally competent approach reflected the ethnic beliefs, values, customs, food preferences, language, learning methods, and health care practices of southern African Americans.

Results

Body mass index and dietary fat behaviors were significantly lowered in the experimental group. At 6 months, weight decreased 1.8 kg (4 lb) for the experimental group and increased 1.9 kg (4.2 lb) for the control group, a net difference of 3.7 kg (8.2 lb). The experimental group reduced high-fat dietary habits to moderate while high-fat dietary habits of the control group remained essentially unchanged. A trend in reduction of A1C and lipids was observed.

Conclusions

Results suggest the effectiveness of a culturally competent dietary self-management intervention in improving health outcomes for southern African Americans, especially those at risk due to high-fat diets and body mass index ≥ 35 kg/mm2. Given the burgeoning problem of obesity in South Carolina and the nation, the time has come to focus on aggressive weight management. Diabetes educators are in pivotal positions to assume leadership in achieving this goal for vulnerable, rural populations.

Relationship between glycated albumin and glycated hemoglobin according to glucose tolerance status: A multicenter study

AIMS

To determine the relationship between glycated albumin (GA) and glycated hemoglobin (HbA1c) and to explore the association of glycated albumin/glycated hemoglobin (GA/HbA1c) ratio with glucose indices in Chinese subjects with varying glucose tolerance status.

METHODS

This hospital-based, cross-sectional study involved 953 participants without known diabetes from 11 centers in China. Oral glucose tolerance test (OGTT) was used to identify three groups of subjects: normal glucose regulation (n=194), impaired glucose regulation (n=303) and newly diagnosed type 2 diabetes group (n=456). The GA, HbA1c and GA/HbA1c ratio were tested.

RESULTS

GA was positively correlated with HbA1c (r=0.832, P<0.001). After correcting for age, sex and BMI, the correlations remained significant (r=0.824, P<0.001). Linear regression analysis estimated that a 1% increase of HbA1c was associated with a 2.84% increase of GA (GA=2.843×HbA1c-0.203; R(2)=0.692, P<0.001). GA would be 18.3 (16.7-19.9)% and 19.7 (18.0-21.4)% with HbA1c of 6.5% (48mmol/mol) and 7.0% (53mmol/mol). The mean GA/HbA1c ratio was 2.81±0.38, and it significantly increased with the presence of glucose intolerance (all, P<0.05). In the total study population, GA/HbA1c was correlated with BMI, glucose levels and 30-min insulin during OGTT, the homeostatic model assessment of β-cell function (HOMA-β), and ΔI30/ΔG30 (all, P<0.05). Increased glucose at 30min (standardized β=0.221, P<0.001), and decreased BMI (standardized β=-0.114, P=0.008) were associated with elevated GA/HbA1c ratio by multiple linear regression (adjusted R(2)=0.045).

CONCLUSIONS

The relationship between GA and HbA1c was strong. The GA/HbA1c ratio was related to acute postprandial glucose fluctuation and BMI level.

Standardising HbA1c-based diabetes diagnosis: opportunities and challenges

Globally, the incidence of diabetes mellitus is rising at an alarming rate and has become a health crisis that threatens the economies of all nations. Therefore, diagnosing diabetes has become an important issue in the management of diabetes. Glycated hemoglobin (HbA1c) is now recommended as a means to diagnose diabetes, but its use still has limitations. In this article, the biology, measurement, standardization, and opportunities and challenges of the use of HbA1c to diagnose diabetes are reviewed. More specifically, its use in China and the Asian region is discussed in detail.

Glycated serum albumin: a potential disease marker and an intermediate index of diabetes control

Glycation is a non-enzymatic spontaneous process in proteins which has remarkable impact on its physical and functional aspect. This alteration with addition of carbohydrate residue to human serum albumin leads to several pathological events such as diabetic nephropathy, neuropathy, retinopathy and cardiovascular complications. Human serum albumin is the major protein and is most susceptible to non-enzymatic glycation. Structural and biological properties of functional albumin alter due to the addition of reducing carbohydrate to free amino terminal residues vivo. These irreversible changes in functional albumin are stable which makes this modified albumin as new gold standard future diagnostic marker in diabetes associated complications. Glycated albumin can be used to determine the glycemic control due to short half life than erythrocytes which makes it an alternate reliable disease marker in diabetes. In this review, Human serum albumin glycation has been overviewed, stating concept of glycation and sites that are prone to this modifications. Impact of non-enzymatic addition of carbohydrate to albumin's structural and biological properties has also been elaborated. Accurate measurements of glycated albumin with implications of new highly sensitive techniques have also been described briefly. Interestingly human serum albumin imposed glycation can serve as future tool not for diagnosing diabetes but also its potential in assessment of diabetes associated complications.

HbA1c in pregnancy

During pregnancy, the glucose levels vary according to the hormonal changes and the metabolic needs necessary to maintain fetal nutrition but strict glycemic control is essential to minimize the maternal and fetal morbidity and mortality of pregnancies complicated by diabetes. Although considered the "gold standard" for diagnosis, measurement of glucose in the blood is subject to several limitations, many of which are not widely appreciated. Measurement of A1c for diagnosis is appealing as with one number, a total, integrated view of glycemia over time is derived though it has some inherent limitations. Thus, supplementation with HbA1c, as is common outside pregnancy, seems appropriate. Before pregnancy, the target for metabolic control in women with diabetes is HbA1c values near the normal range. However, the upper normal range of HbA1c during normal pregnancy is only sparsely investigated with different methods though recently a number of papers have been published regarding the determination of reference ranges for HbA1c in pregnancy. These changes may have clinical implications for the assessment and management of glycemic control in diabetic pregnancy and calls for establishment of separate reference limits of HbA1c levels in different trimesters as compared to general population.

Predictive value of HbA1c for incident diabetes among subjects with impaired glucose tolerance--analysis of the Indian Diabetes Prevention Programmes

AIMS

The objectives of the study were to assess the predictive value of baseline HbA(1c) for incident diabetes among the participants with impaired glucose tolerance in the Indian Diabetes Prevention Programmes 1 and 2.

METHODS

Data at baseline and at 3-year follow-up were analysed in combined cohorts of the Indian Diabetes Prevention Programmes 1 and 2. Within the 3 years, 324 of the 845 participants developed diabetes (World Health Organization criteria). The predictive value of baseline HbA(1c) for incident diabetes was determined by logistic regression analysis.

RESULTS

Baseline HbA(1c) values had heterogenous distribution. The distribution was similar in isolated impaired glucose tolerance or in impaired glucose tolerance in combination with impaired fasting glucose. A progressive increase in diabetes occurred with increasing HbA(1c). HbA(1c) showed the strongest association with incident diabetes in the multiple logistic regression analysis (odds ratio 3.548, P < 0.0001). The cut-off HbA(1c) of 43 mmol/mol (6.05%) had 67% sensitivity and 60% specificity to predict future diabetes. The diagnostic sensitivity of HbA(1c) of ≥ 48 mmol/mol (≥ 6.5%) was only 51%, with a specificity of 87%, when compared with the oral glucose tolerance glucose values.

CONCLUSIONS

Baseline HbA(1c) was highly predictive of future diabetes in Asian Indian subjects with impaired glucose tolerance and nearly 60% of the incidence occurred with values ≥ 42 mmol/mol (≥ 6.0). Diagnostic sensitivity of HbA(1c) ≥ 48 mmol/mol (≥ 6.5%) for new diabetes was only 51% using the oral glucose tolerance test as the standard for comparison.

Implications of the new definition of diabetes for health disparities

In July 2009, an international committee announced a new diagnostic criterion for diabetes based on hemoglobin Alc (HbA1c) values. Our objective was to estimate how the new diabetes diagnostic criterion will affect the prevalence of diabetes among different race, age, and gender subpopulations, compared to the previously used fasting plasma glucose (FPG) criterion. We analyzed nationally representative data from The National Health and Nutrition Examination Survey (NHANES), aggregated from 1999 to 2006. We estimated the prevalence of known diabetes (prevalence static across either diagnostic criterion), unknown, and no diabetes (prevalence variable by criterion). We tested statistical significance of prevalence differences for unknown diabetes between the prior diagnostic criterion--FPG of at least 126 mg/dL--and the new diagnostic criterion--HbA1c of at least 6.5%--using conditional logistic regression. We further tested the association of these differences with demographic factors. The new HbA1c diagnostic criterion differentially affects different racial/ethnic groups. For non-Hispanic whites, the prevalence of undiagnosed diabetes was more than halved from 2.6% (95% confidence interval [CI], 2.2-3.1) with FPG diagnosis to 1.3% (95% CI, 1.0-1.7), P<.001 with HbAic diagnosis. For Hispanics and non-Hispanic blacks, the differences in prevalence by the 2 criteria were smaller and nonsignificant. Racial differences by diagnostic criteria were most pronounced among people aged over 55 years. Overall, the new definition of diabetes differentially affects ethnic groups, especially for older people. If the new criterion is widely adopted, over time, we may see an apparent widening of racial/ethnic disparities in diabetes prevalence.

Status of hemoglobin A1c measurement and goals for improvement: from chaos to order for improving diabetes care

BACKGROUND

The Diabetes Control and Complications Trial (DCCT) and United Kingdom Prospective Diabetes Study (UKPDS) established the importance of hemoglobin A(1c) (Hb A(1c)) as a predictor of outcome in patients with diabetes mellitus. In 1994, the American Diabetes Association began recommending specific Hb A(1c) targets, but lack of comparability among assays limited the ability of clinicians to use these targets. The National Glycohemoglobin Standardization Program (NGSP) was implemented in 1996 to standardize Hb A(1c) results to those of the DCCT/UKPDS.

CONTENT

The NGSP certifies manufacturers of Hb A(1c) methods as traceable to the DCCT. The certification criteria have been tightened over time and the NGSP has worked with the College of American Pathologists in tightening proficiency-testing requirements. As a result, variability of Hb A(1c) results among clinical laboratories has been considerably reduced. The IFCC has developed a reference system for Hb A(1c) that facilitates metrological traceability to a higher order. The NGSP maintains traceability to the IFCC network via ongoing sample comparisons. There has been controversy over whether to report Hb A(1c) results in IFCC or NGSP units, or as estimated average glucose. Individual countries are making this decision.

SUMMARY

Variability among Hb A(1c) results has been greatly reduced. Not all countries will report Hb A(1c) in the same units, but there are established equations that enable conversion between different units. Hb A(1c) is now recommended for diagnosing diabetes, further accentuating the need for optimal assay performance. The NGSP will continue efforts to improve Hb A(1c) testing to ensure that clinical needs are met.

Do race and ethnicity impact hemoglobin A1c independent of glycemia?

Hemoglobin A1c (HbA1c) is widely used as an index of mean glycemia, a measure of risk for the development of diabetes complications, and a measure of the quality of diabetes care. Emerging literature suggests that, although HbA1c levels change little over time within persons without diabetes, they vary considerably among individuals, suggesting that factors other than glycemia may impact HbA1c. Racial and ethnic differences in HbA1c have been described that do not appear to be explained by differences in glycemia. It is imperative that the nonglycemic factors that affect HbA1c be more clearly defined. Even more important, it must be determined whether differences among individuals or groups correlate with susceptibility to complications or merely reflect variation in hemoglobin glycation.

HbA1c: how do we measure it and what does it mean?

PURPOSE OF REVIEW

Description of recent developments in the standardization of HbA1c measurement and interpretation of HbA1c results.

RECENT FINDINGS

HbA1c is extensively used in the management of patients with diabetes. The two major schemes to standardize HbA1c produce values that differ substantially. A prospective, multinational study revealed a linear correlation between HbA1c and average blood glucose. Some, but not all, assay methods are able to accurately measure HbA1c in individuals with common hemoglobin variants.

SUMMARY

Progress in standardization of methods for HbA1c measurement has significantly reduced variation among different methods. The improved accuracy could allow HbA1c to be used for screening and diagnosis of diabetes. A consensus document recommends that HbA1c be reported in both NGSP (%) and IFCC (mmol/mol) units. HbA1c results can be translated into estimated average glucose (eAG), which could be reported in addition to HbA1c.

Differences in A1C by race and ethnicity among patients with impaired glucose tolerance in the Diabetes Prevention Program

OBJECTIVE

We sought to examine racial and ethnic differences in A1C in individuals with impaired glucose tolerance (IGT).

RESEARCH DESIGN AND METHODS

We studied 3,819 individuals aged > or = 25 years with IGT who were found to be eligible to participant in the Diabetes Prevention Program. A1C was compared among five racial and ethnic groups before and after adjustment for factors that differed among groups or might affect glycemia including age, sex, education, marital status, blood pressure, adiposity (BMI and waist circumference), hematocrit, fasting and post-glucose load glucose levels, glucose area under the curve (AUC), beta-cell function, and insulin resistance.

RESULTS

Mean +/- SD A1C was 5.91 +/- 0.50%. Among whites, A1C was 5.80 +/- 0.44%, among Hispanics 5.89 +/- 0.46%, among Asian 5.96 +/- 0.45%, among American Indians 5.96 +/- 0.46%, and among blacks 6.19 +/- 0.59%. Age, sex, systolic blood pressure, diastolic blood pressure, BMI, fasting glucose, glucose AUC, corrected insulin response, and insulin resistance were each independent predictors of A1C. Adjusting for these and other factors, mean A1C levels were 5.78% for whites, 5.93% for Hispanics, 6.00% for Asians, 6.12% for American Indians, and 6.18% for blacks (P < 0.001).

CONCLUSIONS

A1C levels are higher among U.S. racial and ethnic minority groups with IGT after adjustment for factors likely to affect glycemia. Among patients with IGT, A1C may not be valid for assessing and comparing glycemic control across racial and ethnic groups or as an indicator of health care disparities.

Comparison of medication adherence and associated health care costs after introduction of pioglitazone treatment in African Americans versus all other races in patients with type 2 diabetes mellitus: a retrospective data analysis

OBJECTIVE

The aim of this study was to compare treatment adherence and health care costs in African Americans versus all other races (All Others) in patients with type 2 diabetes mellitus starting treatment with pioglitazone.

METHODS

In this retrospective cohort study, the North Carolina Medicaid database was used (query dates: July 1, 2000, to June 30, 2003). Using at least 1 code from the International Classification of Diseases, Ninth Revision, Clinical Modification for type 2 diabetes (250.xx) and 1 National Drug Code for antidiabetic medication, we identified a cohort of male and female patients aged > or =18 years with type 2 diabetes who maintained continuous Medicaid eligibility for the entire 36-month follow-up period. Race was categorized as African American and All Others (white, Asian, Native American, Pacific Islander, other) based on self-reported data collected at the time of Medicaid enrollment. Medication adherence was expressed as medication possession ratio (calculated as the number of days of antidiabetic prescription supply dispensed [eg, a 30-day supply] divided by the number of days between the first and last dispensation). Reimbursements made by Medicaid were used to calculate diabetes-related and total health care costs, which included medical and dental care, including costs for regular checkups, office visits, home health care, inpatient and outpatient care, long-term care facility care, and prescription drugs. To compare the differences in medication adherence and annual total and diabetes-related health care costs between African Americans and All Others, multivariate regression analysis was performed using only data from the year after (year 2) the year in which pioglitazone treatment was started (year 1).

RESULTS

Among the 1073 patients treated with pioglitazone (26.1% men; mean [SD] age, 49.5 [10.6] years; 50.2% African American; mean [SD] total health care costs in year 1, US $7906 [$12,256]; year 2, $9546 [$14,861]), African Americans had significantly higher adherence (62%) to pioglitazone treatment compared with All Others (57%) (P < 0.05) on unadjusted analysis. However, no significant differences in rates of adherence to the medication were found between African Americans and All Others on multivariate regression analysis. African American race was not found to be an independent predictor of increased or decreased annual total health care costs in this population. Significant reductions in total health care costs (2% for every 10% increase in adherence; P < 0.001) and diabetes-related costs (4% for every 10% increase in adherence; P < 0.01) with increased adherence were found.

CONCLUSIONS

On multivariate analysis, this study found no significant differences in treatment adherence between African Americans versus all other races in this population of diabetic patients enrolled in a Medicaid program (query dates: July 1, 2000, to June 30, 2003). A higher adherence rate was associated with significantly lower diabetes-related and total health care costs in this population.

Haemoglobin A1c is not a surrogate for glucose and insulin measures for investigating the early life and childhood determinants of insulin resistance and Type 2 diabetes in healthy children. An analysis from the Avon Longitudinal Study of Parents and Children (ALSPAC)

AIMS

Research into early life and childhood determinants of insulin resistance and Type 2 diabetes are complicated by requirements for fasting blood samples and glucose tolerance tests. We investigated haemoglobin A(1c) (HbA(1c)), a marker of glycaemia measured in non-fasting blood, as an alternative.

METHODS

HbA(1c) was measured in 1645 children aged 9-11 years without diabetes from the Avon Longitudinal Study of Parents and Children. Thirty-nine children had two HbA(1c) measurements. Data on parental, child and potential confounding factors were collected prospectively from questionnaires, medical records and direct examination. Data from a shortened 30-min oral glucose tolerance test were available for 431 children at age 8 years. Body composition was measured by dual-energy X-ray absorptiometry.

RESULTS

Mean (sd) HbA(1c) was 4.91(0.29)%. HbA(1c) increased with age and was higher in boys compared with girls, non-white compared with white children, and in children with anaemia. Mean difference between repeated HbA(1c) measurements was 0.01%. HbA(1c) was weakly positively associated with fasting glucose (beta = 0.066%/mmol/l, P = 0.05), but was not associated with 30-min glucose, fasting or 30-min insulin, or homeostasis model assessment-insulin resistance. HbA(1c) was weakly inversely associated with weight sd score (beta =-0.02%/unit, P = 0.004), body mass index sd score (beta = -0.02%/unit, P = 0.002), and total body fat (beta = -0.003%/kg, P = 0.06) and lean mass (beta = -0.011%/kg, P = 0.01), but was not associated with birthweight or breastfeeding.

CONCLUSIONS

HbA(1c) is not a good marker of fasting or post-load glucose and insulin measures in healthy children, and is not a viable alternative to these measures for investigating the determinants of insulin resistance and Type 2 diabetes in children.

Disparities in HbA1c levels between African-American and non-Hispanic white adults with diabetes: a meta-analysis

OBJECTIVE

Among individuals with diabetes, a comparison of HbA(1c) (A1C) levels between African Americans and non-Hispanic whites was evaluated. Data sources included PubMed, Web of Science, the Cumulative Index to Nursing and Allied Health, the Cochrane Library, the Combined Health Information Database, and the Education Resources Information Center.

RESEARCH DESIGN AND METHODS

We executed a search for articles published between 1993 and 2005. Data on sample size, age, sex, A1C, geographical location, and study design were extracted. Cross-sectional data and baseline data from clinical trials and cohort studies for African Americans and non-Hispanic whites with diabetes were included. Diabetic subjects aged <18 years and those with pre-diabetes or gestational diabetes were excluded. We conducted a meta-analysis to estimate the difference in the mean values of A1C for African Americans and non-Hispanic whites.

RESULTS

A total of 391 studies were reviewed, of which 78 contained A1C data. Eleven had data on A1C for African Americans and non-Hispanic whites and met selection criteria. A meta-analysis revealed the standard effect to be 0.31 (95% CI 0.39-0.25). This standard effect correlates to an A1C difference between groups of approximately 0.65%, indicating a higher A1C across studies for African Americans. Grouping studies by study type (cross-sectional or cohort), method of data collection for A1C (chart review or blood draw), and insurance status (managed care or nonmanaged care) showed similar results.

CONCLUSIONS

The higher A1C observed in this meta-analysis among African Americans compared with non-Hispanic whites may contribute to disparity in diabetes morbidity and mortality in this population.

Race differences in long-term diabetes management in an HMO

OBJECTIVE

We examined race differences in diabetes outcomes over 4-8 years in a single HMO.

RESEARCH DESIGN AND METHODS

We identified black and white adult diabetic patients who were continuously enrolled (1992-2001) and in whom diabetes was 1) diagnosed before 1994 (n = 1,686) or 2) newly diagnosed in 1994-1997 (n = 1,280). We used hierarchical models to estimate the effect of race on average annual HbA(1c) (A1C) controlling for baseline A1C, BMI, and age, as well as annual measures of type of diabetes medications, diabetes-related hospitalization, time and the number of A1C tests, physician visits, and nondiabetes medications. Stratifying by sex accounted for significant interactions between sex and race.

RESULTS

At baseline, black and white patients had similar rates of A1C testing and physician visits, but blacks had higher unadjusted A1C values. In multivariate models, among patients with previously diagnosed diabetes, average A1C was nonsignificantly 0.11 higher (95% CI -0.12 to 0.34) in black than in white men but was 0.30 higher (0.14-0.46; P = 0.0007) in black than in white women. Among patients with newly diagnosed diabetes, the adjusted black-white gap was 0.49 among men (0.17-0.80; P = 0.007) and was 0.05 among women (-0.20 to -0.31), which was positive but not significant.

CONCLUSIONS

Factors other than the quality of care may explain persistent race differences in A1C in this setting. Future interventions should target normalization of A1C by identifying potential psychosocial barriers to therapy intensification among patients and clinicians and development of culturally appropriate interventions to aid patients in successful self-management.

Ethnic Disparities: Control of Glycemia, Blood Pressure, and LDL Cholesterol Among US Adults with Type 2 Diabetes

OBJECTIVE:

To examine ethnic disparities in the quality of diabetes care among adults with diabetes in the US through a systematic qualitative review.

DATA SOURCES:

Material published in the English language was searched from 1993 through June 2003 using PubMed, Web of Science, Cumulative Index to Nursing and Allied Health, the Cochrane Library, Combined Health Information Database, and Education Resources Information Center.

STUDY SELECTION AND DATA EXTRACTION:

Studies of patients with diabetes in which at least 50% of study participants were ethnic minorities and studies that made ethnic group comparisons were eligible. Research on individuals having prediabetes, those <18 years of age, or women with gestational diabetes were excluded. Reviewers used a reproducible search strategy. A standardized abstraction and grading of articles for publication source and content were used. Data on glycemia, blood pressure, and low-density lipoprotein cholesterol (LDL-C) were extracted in patients with diabetes. A total of 390 studies were reviewed, with 78 meeting inclusion criteria.

DATA SYNTHESIS:

Ethnic minorities had poorer outcomes of care than non-Hispanic whites. These disparities were most pronounced for glycemic control and least evident for LDL-C control. Most studies showed blood pressure to be poorly controlled among ethnic minorities.

CONCLUSIONS:

Control of risk factors for diabetes (glycemia, blood pressure, LDL-C) is challenging and requires routine assessment. These findings indicate that additional efforts are needed to promote diabetes quality of care among minority populations.

Ethnic differences in mortality, end-stage complications, and quality of care among diabetic patients: a review

OBJECTIVE

To determine the influence of ethnic differences in diabetes care on inequalities in mortality and prevalence of end-stage complications among diabetic patients. The following questions were examined: 1) Are there ethnic differences among diabetic patients in mortality and end-stage complications and 2) are there ethnic differences among diabetic patients in quality of care?

RESEARCH DESIGN AND METHODS

A review of the literature on ethnic differences in the prevalence of complications and mortality among diabetic patients and in the quality of diabetes care was performed by systematically searching articles on Medline published from 1987 through October 2004.

RESULTS

A total of 51 studies were included, mainly conducted in the U.S. and the U.K. In general, after adjusting for confounders, diabetic patients from ethnic minorities had higher mortality rates and higher risk of diabetes complications. After additional adjustment for risk factors such as smoking, socioeconomic status, income, years of education, and BMI, in most instances ethnic differences disappear. Nevertheless, blacks and Hispanics in the U.S. and Asians in the U.K. have an increased risk of end-stage renal disease, and blacks and Hispanics in the U.S. have an increased risk of retinopathy. Intermediate outcomes of care were worse in blacks, and they were inclined to be worse in Hispanics. Likewise, ethnic differences in quality of care in the U.S. exist: process of care was worse in blacks.

CONCLUSIONS

Given the fact that there are ethnic differences in diabetes care and that ethnic differences in some diabetes complications persist after adjustment for risk factors other than diabetes care, it seems the case that ethnic differences in diabetes care contribute to the more adverse disease outcomes of diabetic patients from some ethnic minority groups. Although no generalizations can be made for all ethnic groups in all regions for all kinds of complications, the results do implicate the importance of quality of care in striving for equal health outcomes among ethnic minorities.

Predictors of glycemic control among patients with Type 2 diabetes: a longitudinal study

BACKGROUND

Diabetes is the sixth leading cause of death and results in significant morbidity. The purpose of this study is to determine what demographic, health status, treatment, access/quality of care, and behavioral factors are associated with poor glycemic control in a Type 2 diabetic, low-income, minority, San Diego population.

METHODS

Longitudinal observational data was collected on patients with Type 2 diabetes from Project Dulce, a program in San Diego County designed to care for an underserved diabetic population. The study sample included 573 patients with a racial/ethnic mix of 53% Hispanic, 7% black, 18% Asian, 20% white, and 2% other. We utilized mixed effects models to determine the factors associated with poor glycemic control using hemoglobin A1C (A1C) as the outcome of interest. A multi-step model building process was used resulting in a final parsimonious model with main effects and interaction terms.

RESULTS

Patients had a mean age of 55 years, 69% were female, the mean duration of diabetes was 7.1 years, 31% were treated with insulin, and 57% were obese. American Diabetes Association (ADA) recommendations for blood pressure and total cholesterol were met by 71% and 68%, respectively. Results of the mixed effects model showed that patients who were uninsured, had diabetes for a longer period of time, used insulin or multiple oral agents, or had high cholesterol had higher A1C values over time indicating poorer glycemic control. The younger subjects also had poorer control.

CONCLUSION

This study provides factors that predict glycemic control in a specific low-income, multiethnic, Type 2 diabetic population. With this information, subgroups with high risk of disease morbidity were identified. Barriers that prevent these patients from meeting their goals must be explored to improve health outcomes.

Pounds off with empowerment (POWER): a clinical trial of weight management strategies for black and white adults with diabetes who live in medically underserved rural communities

OBJECTIVES

We evaluated lifestyle interventions for diabetic persons who live in rural communities.

METHODS

We conducted a 12-month randomized clinical trial (n = 152) of "intensive-lifestyle" (modeled after the NIH Diabetes Prevention Program) and "reimbursable-lifestyle" (intensive-lifestyle intervention delivered in the time allotted for Medicare reimbursement for diabetes education related to nutrition and physical activity) interventions with usual care as a control.

RESULTS

Modest weight loss occurred by 6 months among intensive-lifestyle participants and was greater than the weight loss among usual-care participants (2.6 kg vs 0.4 kg, P<.01). At 12 months, a greater proportion of intensive-lifestyle participants had lost 2 kg or more than usual-care participants (49% vs 25%, P<.05). No differences in weight change were observed between reimbursable-lifestyle and usual-care participants. Glycated hemoglobin was reduced among all groups (P<.05) but was not different between groups.

CONCLUSIONS

Improvement in both weight and glycemia was attainable by lifestyle interventions designed for persons who had type 2 diabetes and lived in rural communities.

Effect of pramlintide on A1C and body weight in insulin-treated African Americans and Hispanics with type 2 diabetes: a pooled post hoc analysis

An unresolved problem in the management of type 2 diabetes is that improvement of glycemic control with insulin, insulin secretagogues, and insulin sensitizers is often accompanied by undesired weight gain. This problem is of particular concern in ethnic groups with a high propensity for diabetes and obesity, such as African Americans and Hispanics. Two 1-year, randomized, double-blind, placebo-controlled clinical trials in insulin-treated patients with type 2 diabetes have shown that adjunctive therapy with pramlintide, an analog of the human beta-cell hormone amylin, reduces A(1C) with concomitant weight loss, rather than weight gain. To assess the effect of pramlintide in various ethnic groups with type 2 diabetes using insulin, we conducted a pooled post hoc analysis of the 2 trials, which included all Caucasian (n = 315), African American (n = 47), and Hispanic (n = 48) patients (age 57 years, A(1C) 9.1%, body mass index [BMI] 33 kg/m(2), mean values) who completed 52 weeks of treatment with either pramlintide (120 microg twice daily or 150 microg 3 times a day) or placebo. Primary endpoints included changes from baseline to week 52 in A(1C) and body weight. Collectively, pramlintide-treated patients achieved significant reductions from baseline in both A(1C) and body weight (placebo-corrected treatment effects at week 52: -0.5% and -2.6 kg, respectively, both P <.0001). The simultaneous reduction in A(1C) and body weight at week 52 was evident across all 3 ethnic groups and appeared to be most pronounced in African Americans (-0.7%, -4.1 kg), followed by Caucasians (-0.5%, -2.4 kg) and Hispanics (-0.3%, -2.3 kg). The glycemic improvement with pramlintide was not associated with an increased incidence of hypoglycemia over the entire study period (43% pramlintide v 40% placebo). Nausea, the most common adverse event associated with pramlintide treatment, was mostly mild and confined to the first 4 weeks of therapy (25% pramlintide v 16% placebo) with comparable patterns in the 3 ethnic groups. Thus, pending further experience, the combined improvement in glycemic and weight control with pramlintide treatment appears to be generalizable to a broad population of mixed ethnicity.

Racial Disparities in Diabetes Care Processes, Outcomes, and Treatment Intensity

BACKGROUND

Black Americans with diabetes have a higher burden of illness and mortality than do white Americans. However, the extent to which differences in medical care processes and treatment intensity contribute to poorer diabetes outcomes is unknown.

OBJECTIVE

To assess racial disparities in the quality of diabetes care processes, intermediate outcomes, and treatment intensity.

METHODS

We conducted an observational study of 801 white and 115 black patients who completed the Diabetes Quality Improvement Project survey (response rate=72%) in 21 Veterans Affairs (VA) facilities using survey data; medical record information on receipt of diabetes services (A1c, low-density lipoprotein [LDL], nephropathy screen, and foot and dilated eye examinations), and intermediate outcomes (glucose control measured by A1c; cholesterol control measured by LDL; and achieved level of blood pressure); and pharmacy data on filled prescriptions.

RESULTS

There were no racial differences in receipt of an A1c test or foot examination. Blacks were less likely than whites to have LDL checked in the past 2 years (72% vs. 80%, P<0.05) and to have a dilated eye examination (50% vs. 63%, P<0.01). Even after adjusting for patients' age, education, income, insulin use, diabetes self-management, duration, severity, comorbidities, and health services utilization, racial disparities in receipt of an LDL test and eye examination persisted. After taking into account the nested structure of the data using a random intercepts model, blacks remained significantly less likely to have LDL testing than whites who received care within the same facility (68% vs. 83%, P<0.01). In contrast, there were no longer differences in receipt of eye examinations, suggesting that black patients were more likely to be receiving care at facilities with overall lower rates of eye examinations. After adjusting for patient characteristics and facility effects, black patients were substantially more likely than whites to have poor cholesterol control (LDL > or =130) and blood pressure control (BP > or =140/90 mm Hg) (P<0.01). Among those with poor blood pressure and lipid control, blacks received as intensive treatment as whites for these conditions.

CONCLUSIONS

We found racial disparities in some diabetes care process and intermediate outcome quality measures, but not in intensity of treatment for those patients with poor control. Disparities in receipt of eye examinations were the result of black patients being more likely to receive care at lower-performing facilities, whereas for other quality measures, racial disparities within facilities were substantial.

Effects of dietary intervention on IGF-I and IGF-binding proteins, and related alterations in sex steroid metabolism: the Diet and Androgens (DIANA) Randomised Trial

OBJECTIVE

To assess the effects of a comprehensive change in dietary composition on endogenous hormone metabolism. The specific aim was to examine whether this intervention could lead to favourable changes in insulin sensitivity, levels of IGF-I and IGF-binding proteins (IGFBPs), and total and bioavailable testosterone and estradiol, that would be expected to reduce breast cancer risk.

DESIGN

Randomised dietary intervention study; duration of 5 months.

SUBJECTS

From a total of 99 postmenopausal women, who had elevated baseline plasma testosterone levels, 49 women were randomly assigned to the dietary intervention arm and the other 50 to a control group.

INTERVENTIONS

Main aspects of the dietary intervention were reductions in the intake of total fat and refined carbohydrates, an increase in the ratio of n-3 over n-6 plus saturated fatty acids, and increased intakes of foods rich in dietary fibre and phytooestrogens.

RESULTS

Relative to the control group, women of the intervention group showed a significant reduction of body weight, waist circumference, fasting serum levels of testosterone, C peptide, glucose, and insulin area after glucose tolerance test, and a significant increase of serum levels of sex hormone-binding globulin, IGFBP-1, -2, and growth hormone-binding protein. Serum levels of IGF-I did not change.

CONCLUSION

This comprehensive dietary intervention strategy proved to be successful in inducing changes in endogenous hormone metabolism that might eventually result in reduced breast cancer risk. Additional studies are needed to show whether the dietary intervention and related hormonal changes can be both maintained over longer periods, of at least several years.

Racial differences in glycemic control in a well-functioning older diabetic population: findings from the Health, Aging and Body Composition Study

OBJECTIVE

To evaluate racial differences and factors associated with worse glycemic control in well-functioning older individuals with type 2 diabetes. Our hypothesis was that glycemic control would be worse among black than white diabetic individuals but that this association would be explained by differences in severity of diabetes, health status, health care indicators, and social, psychological, or behavioral factors. We further hypothesized that the association of race with poorer glycemic control would be limited to those with lower education or lower income.

RESEARCH DESIGN AND METHODS

Cross-sectional analysis of 468 diabetic participants among a cohort of 3,075 nondisabled blacks and whites aged 70-79 years living in the community enrolled in the Health, Aging and Body Composition Study. Glycemic control was measured by the level of HbA(1c).

RESULTS

A total of 58.5% of the diabetic individuals were black. Although control was poor in all diabetic participants (HbA(1c) > or =7% in 73.7%), blacks had worse glycemic control than whites (age- and sex-adjusted mean HbA(1c), 8.4% in blacks and 7.4% in whites; P < 0.01). Race differences in glycemic control remained significant, even after adjusting for current insulin therapy, cardiovascular disease, higher total cholesterol, and not receiving a flu shot in the previous year, all of which were associated with higher HbA(1c) concentrations. Controlling for these factors reduced the association by 27%. Race remained an important factor in glycemic control, even when results were stratified by education or income.

CONCLUSIONS

HbA(1c) concentrations were higher in older black diabetic individuals. Differences in glycemic control by race were associated with disease severity, health status, and poorer quality of care, but these factors did not fully explain the higher HbA(1c) levels in older black diabetic individuals.

The Improving Primary Care of African Americans with Diabetes (IPCAAD) project: rationale and design

African Americans have an increased burden of both diabetes and diabetes complications. Since many patients have high glucose levels novel interventions are needed, especially for urban patients with limited resources. In the Grady Diabetes Clinic in Atlanta, a stepped care strategy improves metabolic control. However, most diabetes patients do not receive specialized care. We will attempt to translate diabetes clinic approaches to the primary care setting by implementing a novel partnership between specialists and generalists. We hypothesize that endocrinologist-supported strategies aimed at providers will result in effective diabetes management in primary care sites, and the Improving Primary Care of African Americans with Diabetes project will test this hypothesis in a major randomized, controlled trial involving over 2000 patients. Physicians in Grady Medical Clinic units will receive (1) usual care, (2) computerized reminders that recommend individualized changes in therapy and/or (3) directed discussion by endocrinologists providing feedback on performance. We will measure outcomes related to both microvascular disease (HbA1c, which reflects average glucose levels over an approximately 2-month period) and macrovascular disease (blood pressure and lipids) and assess provider performance as well. We will compare two readily generalizable program interventions that should delineate approaches effective in a primary care setting as needed to improve care and prevent complications in urban African Americans with type 2 diabetes.

Use of diabetes preventive care and complications risk in two African-American communities

BACKGROUND

We examined levels of diabetes preventive care services and glycemic and lipid control among African Americans with diabetes in two North Carolina communities.

METHODS

Cross-sectional, population-based study of 625 African-American adults with diagnosed diabetes. Participants had a household interview to determine receipt of preventive care services including glycosylated hemoglobin (HbA(1c)), blood pressure, lipid, foot, dilated eye, and dental examinations; diabetes education; and health promotion counseling. A total of 383 gave blood samples to determine HbA(1c) and lipid values.

RESULTS

Annual dilated eye, foot, and lipid examinations were reported by 70% to 80% of the population, but only 46% reported HbA(1c) tests. Rates of regular physical activity (31%) and daily self-monitoring of blood glucose (40%) were low. Sixty percent of the population had an HbA(1c) level >8% and one fourth had an HbA(1c) level >10%. Half of the population had a low-density lipoprotein value >130 mg/dL. Lack of insurance was the most consistent correlate of inadequate care (odds ratio [OR]=2.3; 95% confidence interval [CI]=1.3-3.9), having HbA(1c) >9.5% (OR=2.1, 95% CI=1.1-4.2), and LDL levels >130 mg/dL (OR=2.1; 95% CI=1.0-4.5).

CONCLUSIONS

Levels of diabetes preventive care services were comparable to U.S. estimates, but glycemic and lipid control and levels of self-management behaviors were poor. These findings indicate a need to understand barriers to achieving and implementing good glycemic and lipid control among African Americans with diabetes.

African-American women have higher initial HbA1c levels in diabetic pregnancy

OBJECTIVE

African-American women with diabetes are at greater risk for poor glycemic control outside of pregnancy. We evaluated the effect of race on glycemic control in a racially mixed population of women with diabetes entering prenatal care.

RESEARCH DESIGN AND METHODS

HbA1c levels along with demographic data were collected at the first prenatal visit from a group of 234 women with preexisting diabetes. We applied logistic multivariate analysis to identify factors associated with HbA1c levels above the median for the group.

RESULTS

The median HbA1c level for the group was 8%. HbA1c levels were 8.7 +/- 2.0% in African-Americans and 7.7 +/- 1.5% in Caucasians (P < 0.001). African-American racial designation was significantly and independently associated with high HbA1c when controlled for maternal age, parity, White classification, diabetes type, education, marital status, obesity, insurance type, and first trimester entry into care. The effect of race was confined to the nonobese patients, for whom the adjusted odds ratio for African-American race as a predictor of high HbA1c was 8.15 with a 95% CI of 2.41-27.58 (P = 0.001).

CONCLUSIONS

We found a clear racial disparity in glycemic control among women entering prenatal care with preexisting diabetes. This study demonstrates that there generally is need for better glycemic control among reproductive-age women with diabetes, but especially among those who are African-American.

Sociodemographic determinants of glycaemic control in young diabetic patients in peninsular Malaysia

Recent studies have shown that good glycaemic control can prevent the development of diabetic complications in type 1 and type 2 diabetes. We wished to observe the glycaemic control in patients from different centres in Peninsular Malaysia and the factors that determine it. We recruited 926 patients with diabetes diagnosed before age 40 years from seven different centres, with proportionate representation from the three main ethnic groups. Clinical history and physical examination were done and blood taken for HbA1c and fasting glucose. The overall glycaemic control was poor with geometric mean HbA1c of 8.6% whilst 61.1% of the patients had HbA1c greater than 8%. Glycaemic control in patients with type 2 diabetes varied between various centres and ethnic groups, with the best control obtained in Chinese patients. Significant predictors of HbA1c in both type 1 and type 2 diabetes include access to nurse educators, ethnic background and WHR. In type 2 diabetes, use of insulin was a significant predictor, while in type 1 diabetes, household income was a significant predictor. Socioeconomic status did not have a significant effect in type 2 diabetes. There were no significant differences in the glycaemic control in patients with different educational status. In conclusion, glycaemic control in big hospitals in Malaysia was poor, and was closely related to the availability of diabetes care facilities and ethnic group, rather than socioeconomic status.

Effects of mutations in the human uncoupling protein 3 gene on the respiratory quotient and fat oxidation in severe obesity and type 2 diabetes

Human uncoupling protein 3 (UCP3) is a mitochondrial transmembrane carrier that uncouples oxidative ATP phosphorylation. With the capacity to participate in thermogenesis and energy balance, UCP3 is an important obesity candidate gene. A missense polymorphism in exon 3 (V102I) was identified in an obese and diabetic proband. A mutation introducing a stop codon in exon 4 (R143X) and a terminal polymorphism in the splice donor junction of exon 6 were also identified in a compound heterozygote that was morbidly obese and diabetic. Allele frequencies of the exon 3 and exon 6 splice junction polymorphisms were determined and found to be similar in Gullah-speaking African Americans and the Mende tribe of Sierra Leone, but absent in Caucasians. Moreover, in exon 6-splice donor heterozygotes, basal fat oxidation rates were reduced by 50%, and the respiratory quotient was markedly increased compared with wild-type individuals, implicating a role for UCP3 in metabolic fuel partitioning.