OBJECTIVE

To assess trends in rates of hospitalization for nontraumatic lower-extremity amputation (NLEA) in U.S. diabetic and nondiabetic populations and disparities in NLEA rates within the diabetic population.

RESEARCH DESIGN AND METHODS

We calculated NLEA hospitalization rates, by diabetes status, among persons aged ≥40 years on the basis of National Hospital Discharge Survey data on NLEA procedures and National Health Interview Survey data on diabetes prevalence. We used joinpoint regression to calculate the annual percentage change (APC) and to assess trends in rates from 1988 to 2008.

RESULTS

The age-adjusted NLEA discharge rate per 1,000 persons among those diagnosed with diabetes and aged ≥40 years decreased from 11.2 in 1996 to 3.9 in 2008 (APC −8.6%; P < 0.01), while rates among persons without diagnosed diabetes changed little. NLEA rates in the diabetic population decreased significantly from 1996 to 2008 in all demographic groups examined (all P < 0.05). Throughout the entire study period, rates of diabetes-related NLEA were higher among persons aged ≥75 years than among those who were younger, higher among men than women, and higher among blacks than whites.

CONCLUSIONS

From 1996 to 2008, NLEA discharge rates declined significantly in the U.S. diabetic population. Nevertheless, NLEA continues to be substantially higher in the diabetic population than in the nondiabetic population and disproportionately affects people aged ≥75 years, blacks, and men. Continued efforts are needed to decrease the prevalence of NLEA risk factors and to improve foot care among certain subgroups within the U.S. diabetic population that are at higher risk.

Background

Adults with type 2 diabetes mellitus often have limitations in mobility that increase with age. An intensive lifestyle intervention that produces weight loss and improves fitness could slow the loss of mobility in such patients.

Methods

We randomly assigned 5145 overweight or obese adults between the ages of 45 and 74 years with type 2 diabetes to either an intensive lifestyle intervention or a diabetes support-and-education program; 5016 participants contributed data. We used hidden Markov models to characterize disability states and mixed-effects ordinal logistic regression to estimate the probability of functional decline. The primary outcome was self-reported limitation in mobility, with annual assessments for 4 years.

Results

At year 4, among 2514 adults in the lifestyle-intervention group, 517 (20.6%) had severe disability and 969 (38.5%) had good mobility; the numbers among 2502 participants in the support group were 656 (26.2%) and 798 (31.9%), respectively. The lifestyle-intervention group had a relative reduction of 48% in the risk of loss of mobility, as compared with the support group (odds ratio, 0.52; 95% confidence interval, 0.44 to 0.63; P<0.001). Both weight loss and improved fitness (as assessed on treadmill testing) were significant mediators of this effect (P<0.001 for both variables). Adverse events that were related to the lifestyle intervention included a slightly higher frequency of musculoskeletal symptoms at year 1.

Conclusions

Weight loss and improved fitness slowed the decline in mobility in overweight adults with type 2 diabetes. (Funded by the Department of Health and Human Services and others; ClinicalTrials.gov number, NCT00017953.)

OBJECTIVE

To examine whether there were long-term (between 1988–1994 and 2001–2008) and recent (between 2001–2004 and 2005–2008) changes in blood pressure (BP) levels among U.S. adults with diagnosed diabetes.

RESEARCH DESIGN AND METHODS

Using data from National Health and Nutrition Examination Surveys (NHANES), we examined changes in BP distributions, mean BPs, and proportion with BP <140/90 mmHg.

RESULTS

Between 1988–1994 and 2001–2008, for adults with diabetes, mean BPs decreased from 135/72 mmHg to 131/69 mmHg (P < 0.01) and the proportion with BP <140/90 mmHg increased from 64 to 69% (P = 0.01). Although hypertension prevalence increased, hypertension awareness, treatment, and control improved. However, there was no evidence of improvement for adults 20–44 years old. Between 2001–2004 and 2005–2008, there were no significant changes in BP levels.

CONCLUSIONS

BP levels among adults with diabetes improved between 1988–1994 and 2001–2008, but the progress stalled between 2001–2004 and 2005–2008. The lack of improvement among young adults is concerning.

OBJECTIVE

To compare the prevalence of prediabetes using A1C, fasting plasma glucose (FPG), and oral glucose tolerance test (OGTT) criteria, and to examine the degree of agreement between the measures.

RESEARCH DESIGN AND METHODS

We used the 2005–2008 National Health and Nutrition Examination Surveys to classify 3,627 adults aged ≥18 years without diabetes according to their prediabetes status using A1C, FPG, and OGTT. We compared the prevalence of prediabetes according to different measures and used conditional probabilities to examine agreement between measures.

RESULTS

In 2005–2008, the crude prevalence of prediabetes in adults aged ≥18 years was 14.2% for A1C 5.7–6.4% (A1C5.7), 26.2% for FPG 100–125 mg/dL (IFG100), 7.0% for FPG 110–125 mg/dL (IFG110), and 13.7% for OGTT 140–199 mg/dL (IGT). Prediabetes prevalence varied by age, sex, and race/ethnicity, and there was considerable discordance between measures of prediabetes. Among those with IGT, 58.2, 23.4, and 32.3% had IFG100, IFG110, and A1C5.7, respectively, and 67.1% had the combination of either A1C5.7 or IFG100.

CONCLUSIONS

The prevalence of prediabetes varied by the indicator used to measure risk; there was considerable discordance between indicators and the characteristics of individuals with prediabetes. Programs to prevent diabetes may need to consider issues of equity, resources, need, and efficiency in targeting their efforts.

Context

The prevalence of diabetes in the United States has increased. People with diabetes are at risk for diabetic retinopathy. No recent national population-based estimate of the prevalence and severity of diabetic retinopathy exists.

Objectives

To describe the prevalence and risk factors of diabetic retinopathy among US adults with diabetes aged 40 years and older.

Design, Setting, and Participants

Analysis of a cross-sectional, nationally representative sample of the National Health and Nutrition Examination Survey 2005–2008 (N=1006). Diabetes was defined as a self-report of a previous diagnosis of the disease (excluding gestational diabetes mellitus) or glycated hemoglobin A1c of 6.5% or greater. Two fundus photographs were taken of each eye with a digital nonmydriatic camera and were graded using the Airlie House classification scheme and the Early Treatment Diabetic Retinopathy Study severity scale. Prevalence estimates were weighted to represent the civilian, noninstitutionalized US population aged 40 years and older.

Main Outcome Measurements

Diabetic retinopathy and vision-threatening diabetic retinopathy.

Results

The estimated prevalence of diabetic retinopathy and vision-threatening diabetic retinopathy was 28.5% (95% confidence interval [CI], 24.9%–32.5%) and 4.4% (95% CI, 3.5%–5.7%) among US adults with diabetes, respectively. Diabetic retinopathy was slightly more prevalent among men than women with diabetes (31.6%; 95% CI, 26.8%–36.8%; vs 25.7%; 95% CI, 21.7%–30.1%; P=.04). Non-Hispanic black individuals had a higher crude prevalence than non-Hispanic white individuals of diabetic retinopathy (38.8%; 95% CI, 31.9%–46.1%; vs 26.4%; 95% CI, 21.4%–32.2%; P=.01) and vision-threatening diabetic retinopathy (9.3%; 95% CI, 5.9%–14.4%; vs 3.2%; 95% CI, 2.0%–5.1%; P=.01). Male sex was independently associated with the presence of diabetic retinopathy (odds ratio [OR], 2.07; 95% CI, 1.39–3.10), as well as higher hemoglobin A1c level (OR, 1.45; 95% CI, 1.20–1.75), longer duration of diabetes (OR, 1.06 per year duration; 95% CI, 1.03–1.10), insulin use (OR, 3.23; 95% CI, 1.99–5.26), and higher systolic blood pressure (OR, 1.03 per mm Hg; 95% CI, 1.02–1.03).

Conclusion

In a nationally representative sample of US adults with diabetes aged 40 years and older, the prevalence of diabetic retinopathy and vision-threatening diabetic retinopathy was high, especially among Non-Hispanic black individuals.

OBJECTIVE

We examined maximal graded exercise test (GXT) results in 5,783 overweight/obese men and women, aged 45–76 years, with type 2 diabetes, who were entering the Look AHEAD (Action for Health in Diabetes) study, to determine the prevalence and correlates of exercise-induced cardiac abnormalities.

RESEARCH DESIGN AND METHODS

Participants underwent symptom-limited maximal GXTs. Questionnaires and physical examinations were used to determine demographic, anthropometric, metabolic, and health status predictors of abnormal GXT results, which were defined as an ST segment depression ≥1.0 mm, ventricular arrhythmia, angina pectoris, poor postexercise heart rate recovery (<22 bpm reduction 2 min after exercise), or maximal exercise capacity less than 5.0 METs. Systolic blood pressure response to exercise was examined as a continuous variable, without a threshold to define abnormality.

RESULTS

Exercise-induced abnormalities were present in 1,303 (22.5%) participants, of which 693 (12.0%) consisted of impaired exercise capacity. ST segment depression occurred in 440 (7.6%), abnormal heart rate recovery in 206 (5.0%), angina in 63 (1.1%), and arrhythmia in 41 (0.7%). Of potential predictors, only greater age was associated with increased prevalence of all abnormalities. Other predictors were associated with some, but not all, abnormalities. Systolic blood pressure response decreased with greater age, duration of diabetes, and history of cardiovascular disease.

CONCLUSIONS

We found a high rate of abnormal GXT results despite careful screening for cardiovascular disease symptoms. In this cohort of overweight and obese individuals with type 2 diabetes, greater age most consistently predicted abnormal GXT. Long-term follow-up of these participants will show whether these abnormalities are clinically significant.

OBJECTIVE

We examined prevalences of previously diagnosed diabetes and undiagnosed diabetes and high risk for diabetes using recently suggested A1C criteria in the U.S. during 2003–2006. We compared these prevalences to those in earlier surveys and those using glucose criteria.

RESEARCH DESIGN AND METHODS

In 2003–2006, the National Health and Nutrition Examination Survey included a probability sample of 14,611 individuals aged ≥12 years. Participants were classified on glycemic status by interview for diagnosed diabetes and by A1C, fasting, and 2-h glucose challenge values measured in subsamples.

RESULTS

Using A1C criteria, the crude prevalence of total diabetes in adults aged ≥20 years was 9.6% (20.4 million), of which 19.0% was undiagnosed (7.8% diagnosed, 1.8% undiagnosed using A1C ≥6.5%). Another 3.5% of adults (7.4 million) were at high risk for diabetes (A1C 6.0 to <6.5%). Prevalences were disproportionately high in the elderly. Age-/sex-standardized prevalence was more than two times higher in non-Hispanic blacks and Mexican Americans versus non-Hispanic whites for diagnosed, undiagnosed, and total diabetes (P < 0.003); standardized prevalence at high risk for diabetes was more than two times higher in non-Hispanic blacks versus non-Hispanic whites and Mexican Americans (P < 0.00001). Since 1988–1994, diagnosed diabetes generally increased, while the percent of diabetes that was undiagnosed and the percent at high risk of diabetes generally decreased. Using A1C criteria, prevalences of undiagnosed diabetes and high risk of diabetes were one-third that and one-tenth that, respectively, using glucose criteria.

CONCLUSIONS

Although A1C detects much lower prevalences than glucose criteria, hyperglycemic conditions remain high in the U.S., and elderly and minority groups are disproportionately affected.

OBJECTIVE

To examine the association of A1C levels and fasting plasma glucose (FPG) with diabetic retinopathy in the U.S. population and to compare the ability of the two glycemic measures to discriminate between people with and without retinopathy.

RESEARCH DESIGN AND METHODS

This study included 1,066 individuals aged ≥40 years from the 2005–2006 National Health and Nutrition Examination Survey. A1C, FPG, and 45° color digital retinal images were assessed. Retinopathy was defined as a level ≥14 on the Early Treatment Diabetic Retinopathy Study severity scale. We used joinpoint regression to identify linear inflections of prevalence of retinopathy in the association between A1C and FPG.

RESULTS

The overall prevalence of retinopathy was 11%, which is appreciably lower than the prevalence in people with diagnosed diabetes (36%). There was a sharp increase in retinopathy prevalence in those with A1C ≥5.5% or FPG ≥5.8 mmol/l. After excluding 144 people using hypoglycemic medication, the change points for the greatest increase in retinopathy prevalence were A1C 5.5% and FPG 7.0 mmol/l. The coefficients of variation were 15.6 for A1C and 28.8 for FPG. Based on the areas under the receiver operating characteristic curves, A1C was a stronger discriminator of retinopathy (0.71 [95% CI 0.66–0.76]) than FPG (0.65 [0.60 – 0.70], P for difference = 0.009).

CONCLUSIONS

The steepest increase in retinopathy prevalence occurs among individuals with A1C ≥5.5% and FPG ≥5.8 mmol/l. A1C discriminates prevalence of retinopathy better than FPG.

Background

People with diabetes can suffer from diverse complications that seriously erode quality of life. Diabetes, costing the United States more than $174 billion per year in 2007, is expected to take an increasingly large financial toll in subsequent years. Accurate projections of diabetes burden are essential to policymakers planning for future health care needs and costs.

Methods

Using data on prediabetes and diabetes prevalence in the United States, forecasted incidence, and current US Census projections of mortality and migration, the authors constructed a series of dynamic models employing systems of difference equations to project the future burden of diabetes among US adults. A three-state model partitions the US population into no diabetes, undiagnosed diabetes, and diagnosed diabetes. A four-state model divides the state of "no diabetes" into high-risk (prediabetes) and low-risk (normal glucose) states. A five-state model incorporates an intervention designed to prevent or delay diabetes in adults at high risk.

Results

The authors project that annual diagnosed diabetes incidence (new cases) will increase from about 8 cases per 1,000 in 2008 to about 15 in 2050. Assuming low incidence and relatively high diabetes mortality, total diabetes prevalence (diagnosed and undiagnosed cases) is projected to increase from 14% in 2010 to 21% of the US adult population by 2050. However, if recent increases in diabetes incidence continue and diabetes mortality is relatively low, prevalence will increase to 33% by 2050. A middle-ground scenario projects a prevalence of 25% to 28% by 2050. Intervention can reduce, but not eliminate, increases in diabetes prevalence.

Conclusions

These projected increases are largely attributable to the aging of the US population, increasing numbers of members of higher-risk minority groups in the population, and people with diabetes living longer. Effective strategies will need to be undertaken to moderate the impact of these factors on national diabetes burden. Our analysis suggests that widespread implementation of reasonably effective preventive interventions focused on high-risk subgroups of the population can considerably reduce, but not eliminate, future increases in diabetes prevalence.

OBJECTIVE—We examined the prevalences of diagnosed diabetes, and undiagnosed diabetes and pre-diabetes using fasting and 2-h oral glucose tolerance test values, in the U.S. during 2005–2006. We then compared the prevalences of these conditions with those in 1988–1994.

RESEARCH DESIGN AND METHODS—In 2005–2006, the National Health and Nutrition Examination Survey included a probability sample of 7,267 people aged ≥12 years. Participants were classified according to glycemic status by interview for diagnosed diabetes and by fasting and 2-h glucoses measured in subsamples.

RESULTS—In 2005–2006, the crude prevalence of total diabetes in people aged ≥20 years was 12.9%, of which ∼40% was undiagnosed. In people aged ≥20 years, the crude prevalence of impaired fasting glucose was 25.7% and of impaired glucose tolerance was 13.8%, with almost 30% having either. Over 40% of individuals had diabetes or pre-diabetes. Almost one-third of the elderly had diabetes, and three-quarters had diabetes or pre-diabetes. Compared with non-Hispanic whites, age- and sex-standardized prevalence of diagnosed diabetes was approximately twice as high in non-Hispanic blacks (P < 0.0001) and Mexican Americans (P = 0.0001), whereas undiagnosed diabetes was not higher. Crude prevalence of diagnosed diabetes in people aged ≥20 years rose from 5.1% in 1988–1994 to 7.7% in 2005–2006 (P = 0.0001); this was significant after accounting for differences in age and sex, particularly in non-Hispanic blacks. Prevalences of undiagnosed diabetes and pre-diabetes were generally stable, although the proportion of total diabetes that was undiagnosed decreased in Mexican Americans.

CONCLUSIONS—Over 40% of people aged ≥20 years have hyperglycemic conditions, and prevalence is higher in minorities. Diagnosed diabetes has increased over time, but other conditions have been relatively stable.

Introduction

We examined the control of modifiable risk factors among a national sample of diabetic people with and without lower extremity disease (LED).

Methods

The sample from the 1999-2004 National Health and Nutrition Examination Survey consisted of 948 adults aged 40 years or older with diagnosed diabetes and who had been assessed for LED. LED was defined as peripheral arterial disease (ankle-brachial index <0.9), peripheral neuropathy (≥1 insensate area), or presence of foot ulcer. Good control of modifiable risk factors, based on American Diabetes Association recommendations, included being a nonsmoker and having the following measurements: HbA1c less than 7%, systolic blood pressure less than or equal to 130 mm Hg, diastolic blood pressure less than or equal to 80 mm Hg, high density lipoprotein (HDL) cholesterol greater than 50 mg/dL, and body mass index (BMI) between 18.5 kg/m2 and 24.9 kg/m2.

Results

Diabetic people with LED were less likely than were people without LED to have recommended levels of HbA1c (39.3% vs 53.5%) and HDL cholesterol (29.7% vs 41.1%), but there were no differences in systolic or diastolic blood pressure, BMI classification, or smoking status between people with and without LED. Control of some risk factors differed among population subgroups. Notably, among diabetic people with LED, non-Hispanic blacks were more likely to have improper control of HbA1c (adjusted odds ratio [AOR] = 2.0; 95% confidence interval [CI], 1.1-3.9), systolic blood pressure (AOR = 1.9; 95% CI, 1.1-3.2), and diastolic blood pressure (AOR = 2.6; 95% CI, 1.1-5.8), compared with non-Hispanic whites.

Conclusion

Control of 2 of 6 modifiable risk factors was worse in diabetic adults with LED compared with diabetic adults without LED. Among diabetic people with LED, non-Hispanic blacks had worse control of 3 of 6 risk factors compared with non-Hispanic whites.

OBJECTIVE—This study examined the association between access to health care and three classifications of diabetes status: diagnosed, undiagnosed, and no diabetes.

RESEARCH DESIGN AND METHODS—Using data from the 1999–2004 National Health and Nutrition Examination Survey, we identified 110 “missed patients” (fasting plasma glucose >125 mg/dl but without diagnoses of diabetes), 704 patients with diagnosed diabetes, and 4,782 people without diabetes among adults aged 18–64 years. The population percentage undetected among adults with diabetes and the odds ratio of being undetected among adults who reported not having diabetes were compared between groups based on their access to health care.

RESULTS—Among those with diabetes, the percentages having undetected diabetes were 42.2% (95% CI 36.7–47.7) among the uninsured, 25.9% (22.9–28.9) among the insured, 49.3% (43.0–55.6) for those uninsured >1 year, 38.7% (29.2–48.2) for those uninsured ≤1 year, and 24.5% (21.7–27.3) for those continuously insured over the past year. Type of insurance, number of times receiving health care in the past year, and routine patterns of health care utilization were also associated with undetected diabetes. Multivariate adjustment indicated that having undetected diabetes was associated with being uninsured (odds ratio 1.7 [95% CI 1.0–2.9]) and with being uninsured >1 year (2.6 [1.4–5.0]).

CONCLUSIONS—Limited access to health care, especially being uninsured and going without insurance for a long period, was significantly associated with being a “missed patient” with diabetes. Efforts to increase detection of diabetes may need to address issues of access to care.

Background

Our understanding of social disparities in diabetes-related health behaviors is incomplete. The purpose of this study was to determine if having less education is associated with poorer diabetes-related health behaviors.

Methods

This observational study was based on a cohort of 8,763 survey respondents drawn from ~180,000 patients with diabetes receiving care from 68 provider groups in ten managed care health plans across the United States. Self-reported survey data included individual educational attainment ("education") and five diabetes self-care behaviors among individuals for whom the behavior would clearly be indicated: foot exams (among those with symptoms of peripheral neuropathy or a history of foot ulcers); self-monitoring of blood glucose (SMBG; among insulin users only); smoking; exercise; and certain diabetes-related health seeking behaviors (use of diabetes health education, website, or support group in last 12 months). Predicted probabilities were modeled at each level of self-reported educational attainment using hierarchical logistic regression models with random effects for clustering within health plans.

Results

Patients with less education had significantly lower predicted probabilities of being a non-smoker and engaging in regular exercise and health-seeking behaviors, while SMBG and foot self-examination did not vary by education. Extensive adjustment for patient factors revealed no discernable confounding effect on the estimates or their significance, and most education-behavior relationships were similar across sex, race and other patient characteristics. The relationship between education and smoking varied significantly across age, with a strong inverse relationship in those aged 25–44, modest for those ages 45–64, but non-evident for those over 65. Intensity of disease management by the health plan and provider communication did not alter the examined education-behavior relationships. Other measures of socioeconomic position yielded similar findings.

Conclusion

The relationship between educational attainment and health behaviors was modest in strength for most behaviors. Over the life course, the cumulative effect of reduced practice of multiple self-care behaviors among less educated patients may play an important part in shaping the social health gradient.

BACKGROUND: African Americans experience high rates of obesity and other chronic diseases, which may be related, in part, to diet. However, little is known about dietary patterns in this population, particularly from population-based data sources. METHODS: A cross-sectional analysis was conducted of 2,172 African-American adults in Project DIRECT (Diabetes Interventions Reaching and Educating Communities Together). A baseline assessment was conducted using a multistaged population-based probability sample from Raleigh and Greensboro, NC. Daily fruit, vegetable and fat intake was evaluated using a modified version of the Block questionnaire, and then stratified results were analyzed by sociodemographic, health and behavior characteristics. STATA Survey commands were used to account for the complex survey design. RESULTS: Overall, a very small number of participants met national recommendations for > or = 2 servings of fruit (8%) and > or = 3 servings of vegetables (16%) per day. Many participants reported eating high-fat foods; the average daily fat intake was 86 g, and the average daily intake from saturated fat was 24 g. People with more education and higher incomes had a higher average daily fruit intake (all p < 0.05). CONCLUSIONS: The data suggest that participants' fruit, vegetable and fat intake deviated greatly from national guidelines; older people, women, participants with higher socioeconomic status and those who were physically active consumed healthier foods. These data may be useful in developing dietary and weight loss interventions for African Americans.

OBJECTIVE: Patient satisfaction is regarded as a component of the quality of medical care. We examined the association between quality of care and patient satisfaction. DESIGN: Cross-sectional study. SETTING: Population-based random sample in North Carolina, United States, 1997. PARTICIPANTS: 591 African-Americans aged > or = 18 years with self-reported diabetes were interviewed for providers' delivery of 10 preventive measures and patients' performance of four preventive measures for diabetes care. MAIN OUTCOME MEASURES: Satisfaction with health care providers with respect to 11 items, on a 4-point scale (excellent, good, fair, and poor). Average satisfaction scores were compared according to levels of quality of care. RESULTS: Patient satisfaction was positively associated with income, employment, diabetes education, ease of getting care during the last year, having health care coverage and having one physician for diabetes care (P < 0.05 for each). Adjusted for age, sex, education, employment, and income, 8 of 10 preventive care practices by providers during the previous year--monitoring of concentrations of glycosylated hemoglobin (HbA1c) and cholesterol; performing eye, foot, and gum examinations; and physician counseling on self-monitoring of blood glucose concentrations, exercise, and weight reduction--were associated with higher satisfaction scores (P < 0.05). Patients' performance of three of four preventive practices--taking medications for diabetes as prescribed, performing daily self-examination of the feet, and going for an eye examination with dilation of the pupils--were also associated with higher satisfaction scores (P < 0.05). CONCLUSION: Quality of diabetes care was positively associated with patient satisfaction with provider of care. Prospective studies are needed to confirm this association and its direction.