A multivariate logistic regression equation to screen for dysglycaemia: development and validation.

AIMS: To develop and validate an empirical equation to screen for dysglycaemia [impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and undiagnosed diabetes]. METHODS: A predictive equation was developed using multiple logistic regression analysis and data collected from 1032 Egyptian subjects with no history of diabetes. The equation incorporated age, sex, body mass index (BMI), post-prandial time (self-reported number of hours since last food or drink other than water), systolic blood pressure, high-density lipoprotein (HDL) cholesterol and random capillary plasma glucose as independent covariates for prediction of dysglycaemia based on fasting plasma glucose (FPG)>or=6.1 mmol/l and/or plasma glucose 2 h after a 75-g oral glucose load (2-h PG)>or=7.8 mmol/l. The equation was validated using a cross-validation procedure. Its performance was also compared with static plasma glucose cut-points for dysglycaemia screening. RESULTS: The predictive equation was calculated with the following logistic regression parameters: P=1+1/(1+e-X)=where X=-8.3390+0.0214 (age in years)+0.6764 (if female)+0.0335 (BMI in kg/m2)+0.0934 (post-prandial time in hours)+0.0141 (systolic blood pressure in mmHg)-0.0110 (HDL in mmol/l)+0.0243 (random capillary plasma glucose in mmol/l). The cut-point for the prediction of dysglycaemia was defined as a probability>or=0.38. The equation's sensitivity was 55%, specificity 90% and positive predictive value (PPV) 65%. When applied to a new sample, the equation's sensitivity was 53%, specificity 89% and PPV 63%. CONCLUSIONS: This multivariate logistic equation improves on currently recommended methods of screening for dysglycaemia and can be easily implemented in a clinical setting using readily available clinical and non-fasting laboratory data and an inexpensive hand-held programmable calculator.

Controlling the diabetes epidemic: how should we screen for undiagnosed diabetes and dysglycaemia?

AIMS: To compare the detection of undiagnosed diabetes and dysglycaemia (impaired glucose tolerance, impaired fasting glucose, diabetes) using risk factors and laboratory measures of glycaemia. METHODS: Casual blood glucose samples were taken from 1899 (69.4% of 2737 invited) European, Maori and Pacific Islands subjects aged 40-79 years from randomly selected households in South Auckland, New Zealand. Of these, 534 attended for a 75-g oral glucose tolerance test (OGTT) if an elevated result was identified [327/478 (68.4%)] or if randomly selected with a 'normal' screening result [207/308 (67.2%)]. RESULTS: Several Europeans with undiagnosed diabetes (25.0%) and dysglycaemia (31.4%) had no diabetes risk factors. Most Maori and Pacific Islanders had at least one risk factor. The area under the receiver operating curve (ROC) for the detection of undiagnosed diabetes was 0.92 (0.89-0.95) using fasting glucose, 0.86 (0.82-0.90) using HbA1c, 0.75 (0.69-0.80) using random glucose, but 0.60 (0.55-0.66) using risk factor screening. The ROC for detecting any dysglycaemia was 0.88 (0.85-0.90), 0.68 (0.64-0.71), 0.72 (0.69-0.75), 0.61 (0.58-0.65), respectively. Screening using fasting glucose (the best test) detected 90.4% of new diabetes and 78.4% of dysglycaemia; risk factor screening followed by fasting glucose detected significantly less cases [88 (82-93)% and 86 (82-89)%, respectively] with 9.2% less OGTTs. CONCLUSIONS: Using risk factors for the identification of who should receive a blood test for dysglycaemia adds little to direct screening with the risk of missing some with significant hyperglycaemia. Screening for dysglycaemia may best be undertaken using blood tests without initial risk factor symptom screening.

Performance of recommended screening tests for undiagnosed diabetes and dysglycemia.

OBJECTIVE: To evaluate the performance, in settings typical of opportunistic and community screening programs, of screening tests currently recommended by the American Diabetes Association (ADA) for detecting undiagnosed diabetes. RESEARCH DESIGN AND METHODS: Volunteers aged > or =20 years without previously diagnosed diabetes (n = 1,471) completed a brief questionnaire and underwent recording of postprandial time and measurement of capillary blood glucose (CBG) with a portable sensor. Participants subsequently underwent a 75-g oral glucose tolerance test; fasting serum glucose (FSG) and 2-h postload serum glucose (2-h SG) concentrations were measured. The screening tests we studied included the ADA risk assessment questionnaire, the recommended CBG cut point of 140 mg/dl, and an alternative CBG cut point of 120 mg/dl. Each screening test was evaluated against several diagnostic criteria for diabetes (FSG > or =126 mg/dl, 2-h SG > or =200 mg/dl, or either) and dysglycemia (FSG > or =110 mg/dl, 2-h SG > or =140 mg/dl, or either). RESULTS: Among all participants, 10.7% had undiagnosed diabetes (FSG > or =126 or 2-h SG > or =200 mg/dl), 52.1% had a positive result on the questionnaire, 9.5% had CBG > or =140 mg/dl, and 18.4% had CBG > or =120 mg/dl. The questionnaire was 72-78% sensitive and 50-51% specific for the three diabetes diagnostic criteria; CBG > or =140 mg/dl was 56-65% sensitive and 95-96% specific, and CBG > or =120 mg/dl was 75-84% sensitive and 86-90% specific. CBG > or =120 mg/dl was 44-62% sensitive and 89-90% specific for dysglycemia. CONCLUSIONS: Low specificity may limit the usefulness of the ADA questionnaire. Lowering the cut point for a casual CBG test (e.g., to 120 mg/dl) may improve sensitivity and still provide adequate specificity.

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.

Effectiveness of self-management training in type 2 diabetes: a systematic review of randomized controlled trials.

OBJECTIVE: To systematically review the effectiveness of self-management training in type 2 diabetes. RESEARCH DESIGN AND METHODS: MEDLINE, Educational Resources Information Center (ERIC), and Nursing and Allied Health databases were searched for English-language articles published between 1980 and 1999. Studies were original articles reporting the results of randomized controlled trials of the effectiveness of self-management training in people with type 2 diabetes. Relevant data on study design, population demographics, interventions, outcomes, methodological quality, and external validity were tabulated. Interventions were categorized based on educational focus (information, lifestyle behaviors, mechanical skills, and coping skills), and outcomes were classified as knowledge, attitudes, and self-care skills; lifestyle behaviors, psychological outcomes, and quality of life; glycemic control; cardiovascular disease risk factors; and economic measures and health service utilization. RESULTS: A total of 72 studies described in 84 articles were identified for this review. Positive effects of self-management training on knowledge, frequency and accuracy of self-monitoring of blood glucose, self-reported dietary habits, and glycemic control were demonstrated in studies with short follow-up (<6 months). Effects of interventions on lipids, physical activity, weight, and blood pressure were variable. With longer follow-up, interventions that used regular reinforcement throughout follow-up were sometimes effective in improving glycemic control. Educational interventions that involved patient collaboration may be more effective than didactic interventions in improving glycemic control, weight, and lipid profiles. No studies demonstrated the effectiveness of self-management training on cardiovascular disease-related events or mortality; no economic analyses included indirect costs; few studies examined health-care utilization. Performance, selection, attrition, and detection bias were common in studies reviewed, and external generalizability was often limited. CONCLUSIONS: Evidence supports the effectiveness of self-management training in type 2 diabetes, particularly in the short term. Further research is needed to assess the effectiveness of self-management interventions on sustained glycemic control, cardiovascular disease risk factors, and ultimately, microvascular and cardiovascular disease and quality of life.

Population-based estimates of mortality associated with diabetes: use of a death certificate check box in North Dakota.

OBJECTIVES: Overall and cause-specific mortality among persons with diabetes in North Dakota was estimated and compared with estimates from previous population-based studies. METHODS: Data were derived from North Dakota death certificate data, which included unique information on decedents' diabetes status and Behavioral Risk Factor Surveillance System estimates of the diabetic and nondiabetic adult populations of North Dakota. RESULTS: The risk of death among adults with diabetes was 2.6 (2.2, 2.9) times that of adults without diabetes. Relative risks of death among adults with diabetes were at least twice as high for heart disease, cerebrovascular disease, accidents and adverse events, and kidney disease and 70% to 80% higher for pneumonia and influenza, malignant neoplasms, arterial disease, and other causes. Risks remained substantial in the oldest age group. These findings are comparable to results of other population-based studies. CONCLUSIONS: Diabetes status information enhanced the usefulness of death certificate data in examining mortality associated with diabetes and confirms that the effect of diabetes on death is substantial.

Prevalence of type 2 diabetes mellitus in Taiwan: ethnic variation and risk factors.

The purpose of this study was to compare the prevalence of diabetes and risk factors for the disease in three ethnic groups in Taiwan; the Hakaas, Fukienese, and aborigines. A cross-sectional study of men and women aged 50-79 years were invited to attend a standardized interview and physical examination. Diabetes mellitus was defined as a fasting plasma glucose (concentration of greater than or = 126) or a previous diagnosis of diabetes. Demographic, socioeconomic, and risk factor data were obtained. A total of 1293 persons (468 Hakaas, 440 Fukienese, and 385 aborigines) completed the examination. Hakaas had the highest age-adjusted prevalence of diabetes, 17.9% in men and 15.5% in women, followed by Fukienese, 14.5% in men and 12.8% in women. Aborigines had a prevalence of 10.0% in men and 13.3% in women. Diabetes prevalence was positively associated with family history of diabetes, obesity, hypertension, and hypertriglyceridemia. The ethnic variation in diabetes prevalence was reduced after adjustment for age, sex and significant factors. The multivariate-adjusted odds ratios (95% confidence interval) were 1.27 (0.76-2.12) for Fukienese and 1.44 (0.89-2.33) for Hakaas compared with aborigines. Diabetes mellitus is a major public health problem in Taiwan and warrants prevention efforts tailored to the country's different ethnic groups.

Prevalence of diabetes among Native Americans and Alaska Natives, 1990-1997: an increasing burden.

OBJECTIVE: To determine trends in diabetes prevalence among Native Americans and Alaska Natives. RESEARCH DESIGN AND METHODS: From 1990 to 1997, Native Americans and Alaska Natives with diabetes were identified from the Indian Health Service (IHS) national outpatient database, and prevalence was calculated using these cases and estimates of the Native American and Alaskan population served by IHS and tribal health facilities. Prevalence was age-adjusted by the direct method based on the 1980 U.S. population. RESULTS: Between 1990 and 1997, the number of Native Americans and Alaska Natives of all ages with diagnosed diabetes increased from 43,262 to 64,474 individuals. Prevalence of diagnosed diabetes increased by 29%. By 1997, prevalence among Native Americans and Alaska Natives was 5.4%, and the age-adjusted prevalence was 8.0%. During the entire 1990-1997 period, prevalence among women was higher than that among men, but the rate of increase was higher among men than women (37 vs. 25%). In 1997, age-adjusted prevalence of diabetes varied by region and ranged from 3% in the Alaska region to 17% in the Atlantic region. The increase in prevalence between 1990 and 1997 ranged from 16% in the Northern Plains region to 76% in the Alaska region. CONCLUSIONS: Diabetes is common among Native Americans and Alaska Natives, and it increased substantially during the 8-year period examined. Effective interventions for primary, secondary, and tertiary, prevention are needed to address the substantial and rapidly growing burden of diabetes among Native Americans and Alaska Natives.

Diabetes--a common, growing, serious, costly, and potentially preventable public health problem.

An estimated 135 million people worldwide had diagnosed diabetes in 1995, and this number is expected to rise to at least 300 million by 2025. The number of people with diabetes will increase by 42% (from 51 to 72 million) in industrialized countries between 1995 and 2025 and by 170% (from 84 to 228 million) in industrializing countries. Several potentially modifiable risk factors are related to diabetes, including insulin resistance, obesity, physical inactivity and dietary factors. Diabetes may be preventable in high-risk groups, but results of ongoing clinical trials are pending. Several efficacious and economically acceptable treatment strategies are currently available (control of glycemia, blood pressure, lipids; early detection and treatment of retinopathy, nephropathy, foot-disease; use of aspirin and ACE inhibitors) to reduce the burden of diabetes complications. Diabetes is a major public health problem and is emerging as a pandemic. While prevention of diabetes may become possible in the future, there is considerable potential now to better utilize existing treatments to reduce diabetes complications. Many countries could benefit from research aimed at better understanding the reasons why existing treatments are under-used and how this can be changed.

Screening for type 2 diabetes.

Definitive studies of the effectiveness of screening for type 2 diabetes are currently not available. RCTs would be the best means to assess effectiveness, but several barriers prevent these studies from being conducted. Prospective observational studies may characterize some of the benefits of screening by creating screened and unscreened groups for comparison. The availability of better data systems and health services research techniques will facilitate such comparisons. Unfortunately, the interpretation of the results of such studies is extremely problematic. Several screening tests have been evaluated. Risk assessment questionnaires have generally performed poorly as stand-alone tests. Screening with biochemical tests performs better. Venous and capillary glucose measurements may perform more favorably than urinary glucose or HbA(1c) measurements, and measuring postprandial glucose levels may have advantages over measuring fasting levels. However, performance of all screening tests is dependent on the cutoff point selected. Unfortunately, there are no well-defined and validated cutoff points to define positive tests. A two-stage screening test strategy may assist with a more efficient use of resources, although such approaches have not been rigorously tested. The optimal interval for screening is unknown. Even though periodic, targeted, and opportunistic screening within the existing health care system seems to offer the greatest yield and likelihood of appropriate follow-up and treatment, much of the reported experience with screening appears to be episodic poorly targeted community screening outside of the existing health care system. Statistical models have helped to answer some of the key questions concerning areas in which there is lack of empirical data. Current models need to be refined with new clinical and epidemiological information, such as the UKPDS results (200). In addition, future models need to include better information on the natural history of the preclinical phase of diabetes. Data from ongoing clinical trials of screening and treatment of impaired glucose tolerance, such as the Diabetes Prevention Program, may eventually offer more direct evidence for early detection and treatment of asymptomatic hyperglycemia (201). It will be important to use comprehensive cardiovascular disease modules that assess the conjoint influence of glucose and cardiovascular risk factor reduction, information on QOL, and refined economic evaluations using common outcome measures (cost per life-year or QALY gained) (11,178,202-204). Such studies should consider all of the costs associated with a comprehensive screening program, including, at a minimum, the direct costs of screening, diagnostic testing, and care for patients with diabetes detected through screening. Finally, combinations of screening tests and different screening intervals should be evaluated within economic studies to allow selection of the optimal approach within the financial and resource limitations of the health care system.

Diabetes and physical disability among older U.S. adults.

OBJECTIVE: To estimate the prevalence of physical disability associated with diabetes among U.S. adults > or =60 years of age. RESEARCH DESIGN AND METHODS: We analyzed data from a nationally representative sample of 6,588 community-dwelling men and women > or =60 years of age who participated in the Third National Health and Nutrition Examination Survey. Diabetes and comorbidities (coronary heart disease, intermittent claudication, stroke, arthritis, and visual impairment) were assessed by questionnaire. Physical disability was assessed by self-reported ability to walk one-fourth of a mile, climb 10 steps, and do housework. Walking speed, lower-extremity function, and balance were assessed using physical performance tests. RESULTS: Among subjects > or =60 years of age with diabetes, 32% of women and 15% of men reported an inability to walk one-fourth of a mile, climb stairs, or do housework compared with 14% of women and 8% of men without diabetes. Diabetes was associated with a 2- to 3-fold increased odds of not being able to do each task among both men and women and up to a 3.6-fold increased risk of not being able to do all 3 tasks. Among women, diabetes was also associated with slower walking speed, inferior lower-extremity function, decreased balance, and an increased risk of falling. Of the >5 million U.S. adults > or =60 years of age with diabetes, 1.2 million are unable to do major physical tasks. CONCLUSIONS: Diabetes is associated with a major burden of physical disability in older U.S. adults, and these disabilities are likely to substantially impair their quality of life.

Diabetes trends in the U.S.: 1990-1998.

OBJECTIVE: To examine trends in diabetes prevalence in the U.S. RESEARCH DESIGN AND METHODS: This study was conducted via telephone surveys in states that participated in the Behavioral Risk Factor Surveillance System between 1990 and 1998. The participants consisted of noninstitutionalized adults aged 18 years or older. The main outcome measure was self-reported diabetes. RESULTS: The prevalence of diabetes rose from 4.9% in 1990 to 6.5% in 1998--an increase of 33%. Increases were observed in both sexes, all ages, all ethnic groups, all education levels, and nearly all states. Changes in prevalence varied by state. The prevalence of diabetes was highly correlated with the prevalence of obesity (r = 0.64, P<0.001). CONCLUSIONS: The prevalence of diabetes continues to increase rapidly in the U.S. Because the prevalence of obesity is also rising, diabetes will become even more common. Major efforts are needed to alter these trends.

Type 2 diabetes among North American children and adolescents: an epidemiologic review and a public health perspective.

OBJECTIVES: To review the magnitude, characteristics, and public health importance of type 2 diabetes in North American youth. RESULTS: Among 15- to 19-year-old North American Indians, prevalence of type 2 diabetes per 1000 was 50.9 for Pima Indians, 4.5 for all US American Indians, and 2.3 for Canadian Cree and Ojibway Indians in Manitoba. From 1967-1976 to 1987-1996, prevalence increased 6-fold for Pima Indian adolescents. Among African Americans and whites aged 10 to 19 years in Ohio, type 2 diabetes accounted for 33% of all cases of diabetes. Youth with type 2 diabetes were generally 10 to 19 years old, were obese and had a family history of type 2 diabetes, had acanthosis nigricans, belonged to minority populations, and were more likely to be girls than boys. At follow-up, glucose control was often poor, and diabetic complications could occur early. CONCLUSIONS: Type 2 diabetes is an important problem among American Indian and First Nation youth. Other populations have not been well studied, but cases are now occurring in all population groups, especially in ethnic minorities. Type 2 diabetes among youth is an emerging public health problem, for which there is a great potential to improve primary and secondary prevention.