Frank Vinicor

The prevention or delay of type 2 diabetes: American Diabetes Association and National Institute of Diabetes, Digestive and Kidney Diseases

D iabetes is one of the most costly and burdensome chronic diseases of our time and is a condition that is increasing in epidemic proportions in the U.S. and throughout the world (1). The complications resulting from the disease are a significant cause of morbidity and mortality and are associated with the damage or failure of various organs such as the eyes, kidneys, and nerves. Individuals with type 2 diabetes are also at a significantly higher risk for coronary heart disease, peripheral vascular disease, and stroke, and they have a greater likelihood of having hypertension, dyslipidemia, and obesity (2–6). There is also growing evidence that at glucose levels above normal but below the diabetes threshold diagnostic now referred to as pre-diabetes, there is a substantially increased risk of cardiovascular disease (CVD) and death (5,7–10). In these individuals, CVD risk factors are also more prevalent (5–7,9,11–14), which further increases the risk but is not sufficient to totally explain it. In contrast to the clear benefit of glucose lowering to prevent or retard the progression of microvascular complications associated with diabetes (15– 18,21), it is less clear whether the high rate of CVD in people with impaired glucose homeostasis, i.e., those with impaired fasting glucose (IFG), impaired glucose tolerance (IGT), or diabetes, is caused by elevated blood glucose levels or will respond to treatments that lower blood glucose. Epidemiological studies have shown a clear relationship (19,20), whereas intervention trials in people with diabetes suggest, but have not demonstrated, a clear benefit of glycemic control (15,16,21,22). Additionally, there are no studies that have investigated a benefit of glucose lowering on macrovascular disease in subjects with only pre-diabetes (IFG or IGT) but not diabetes. Although the treatment of diabetes has become increasingly sophisticated, with over a dozen pharmacological agents available to lower blood glucose, a multitude of ancillary supplies and equipment available, and a clear recognition by health care professionals and patients that diabetes is a serious disease, the normalization of blood glucose for any appreciable period of time is seldom achieved (23). In addition, in well-controlled socalled “intensively” treated patients, serious complications still occur (15–18,21), and the economic and personal burden of diabetes remains. Furthermore, microvascular disease is already present in many individuals with undiagnosed or newly diagnosed type 2 diabetes (11,24– 28). Given these facts, it is not surprising that studies have been initiated in the last decade to determine the feasibility and benefit of various strategies to prevent or delay the onset of type 2 diabetes. Two early reports (29,30) suggested that changes in lifestyle can prevent diabetes, but weaknesses in study design limited their general relevance. Recently, however, four well-designed randomized controlled trials have been reported (31–35). In the Finnish study (31), 522 middleaged (mean age 55 years) obese (mean BMI 31 kg/m) subjects with IGT were randomized to receive either brief diet and exercise counseling (control group) or intensive individualized instruction on weight reduction, food intake, and guidance on increasing physical activity (intervention group). After an average follow-up of 3.2 years, there was a 58% relative reduction in the incidence of diabetes in the intervention group compared with the control subjects. A strong correlation was also seen between the ability to stop the progression to diabetes and the degree to which subjects were able to achieve one or more of the following: lose weight (goal of 5.0% weight reduction), reduce fat intake (goal of 30% of calories), reduce saturated fat intake (goal of 10% of calories), increase fiber intake (goal of 15 g/1,000 kcal), and exercise (goal of 150 min/week). No untoward effects of the lifestyle interventions were observed. In the Diabetes Prevention Program (DPP) (32–34), the 3,234 enrolled subjects were slightly younger (mean age 51 years) and more obese (mean BMI 34 kg/m) but had nearly identical glucose intolerance compared with subjects in the Finnish study. About 45% of the participants were from minority groups (e.g, AfricanAmerican, Hispanic), and 20% were 60 years of age. Subjects were randomized to one of three intervention groups, which included the intensive nutrition and exercise counseling (“lifestyle”) group or either of two masked medication treatment groups: the biguanide metformin group or the placebo group. The latter interventions were combined with standard diet and exercise recommendations. After an average follow-up of 2.8 years (range 1.8–4.6 years), a 58% relative reduction in the progression to diabetes was observed in the lifestyle group (absolute incidence 4.8%), and a 31% relative reduction in the progression of diabetes was observed in the metformin group (absolute incidence 7.8%) compared with control subjects (absolute incidence 11.0%). ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●

The Diabetes Education Study: A Controlled Trial of the Effects of Diabetes Patient Education

The Diabetes Education Study (DIABEDS) was a randomized, controlled trial of the effects of patient and physician education. This article describes a systematic education program for diabetes patients and its effects on patient knowledge, skills, self-care behaviors, and relevant physiologic outcomes. The original sample consisted of 532 diabetes patients from the general medicine clinic at an urban medical center. Patients were predominantly elderly, black women with non-insulin-dependent diabetes mellitus of long duration. Patients randomly assigned to experimental groups (N = 263) were offered up to seven modules of patient education. Each content area module contained didactic instruction (lecture, discussion, audio-visual presentation), skill exercises (demonstration, practice, feedback), and behavioral modification techniques (goal setting, contracting, regular follow-up). Two hundred seventy-five patients remained in the study throughout baseline, intervention, and postintervention periods (August 1978 to July 1982). Despite the requirement that patients demonstrate mastery of educational objectives for each module, postintervention assessment 11–14 mo after instruction showed only rare differences between experimental and control patients in diabetes knowledge. However, statistically significant group differences in self-care skills and compliance behaviors were relatively more numerous. Experimental group patients experienced significantly greater reductions in fasting blood glucose (−27.5 mg/dl versus −2.8 mg/dl, P < 0.05) and glycosylated hemoglobin (−0.43% versus + 0.35%, P < 0.05) as compared with control subjects. Patient education also had similar effects on body weight, blood pressure, and serum creatinine. Continued follow-up is planned for DIABEDS patients to determine the longevity of effects and subsequent impact on emergency room visits and hospitalization.

Plasma Vasopressin in Uncontrolled Diabetes Mellitus

Concentrations of the antidiuretic hormone, arginine vasopressin, were measured in 28 patients with severe hyperglycemia to determine if abnormalities in hormonal regulation of water excretion could contribute to the extreme dehydration of uncontrolled diabetes mellitus. Vasopressin levels were markedly elevated in both nonketotic and ketotic patients, indicating that vasopressin deficiency plays no role in the polyuria that accompanies hyperglycemia. Instead, the observed increases in vasopressin represent an ineffective effort to conserve water in the face of an overwhelming solute diuresis caused by the glucosuria. The reasons for such marked elevations in plasma vasopressin in these diabetic patients are multifactorial. Both groups of diabetic patients had evidence of hypovolemia, which was sufficient in magnitude to stimulate vasopressin release. Furthermore, nausea provided an independent stimulus to vasopressin secretion in many patients. Osmotic stimulation might have resulted from the large fraction of unidentified plasma solutes, but this factor alone was not sufficient to explain the markedly increased concentrations of vasopressin. Whether such elevations in vasopressin could have metabolic and/or hemodynamic effects in uncontrolled diabetes remains to be established.

Effects of the Clinical Environment on Physicians’ Response to Postgraduate Medical Education:

This study examined the effects of a medical education program on diabetes mellitus as a function of the extent to which participants’ clinical environments were made to facilitate recommended practices. One hundred fourteen internal medicine faculty and residents (four clinics) were offered a 3.5-hour diabetes seminar. One clinic served as a seminar-only condition; three clinics received an accumulation of environmental interventions: patient-specific seminar reminders, clinical materials, and easy access to a diabetes patient educator. Relative to control, any degree of environmental support significantly increased prescriptions for home-monitored blood glucose testing. Also, the group of physicians receiving reminders and clinical materials exhibited significantly more frequent utilization of glycosylated hemoglobin as a laboratory measure of metabolic status compared to other groups. No significant differences were obtained for utilization of three other laboratory tests and therapeutic modalities. Developers of postgraduate professional education should consider whether their programs can be strengthened by anticipating how the practice environment facilitates and hinders new professional practices.

The diabetes education study

The Diabetes Education Study was a controlled trial of the effects of physician and patient education. This article describes an educational program for internal medicine residents and its effects on ambulatory diabetes management practices. Forty-five of 86 residents practicing in the general medicine clinic of a university-affiliated city/county hospital were assigned randomly to receive a multifaceted program intended to 1) provide specific care recommendations, 2) teach necessary skills, and 3) make the professional and institutional environment more supportive. During the subsequent 11 months, 323 diabetic patients were interviewed and their records audited for evidence of changes in care. Experimental residents utilized fasting blood glucose determinations more often than controls (i.e., during 40% of visits vs. 31%, p=0.004). Experimental residents also engaged more frequently in a variety of recommended dietary management recommendations. Isolated differences in monitoring/management of chronic complications also were found (e.g., lipid screening: 70% of experimental residents’ patients vs. 58%, p=0.016). Intensive, multifaceted programs of this nature are concluded to result in improvements in diabetes care, over and above that which is attainable through routine methods of clinical training for residents.

The Public Health Burden of Diabetes and the Reality of Limits

Improvements in diabetes surveillance, diagnosis, and treatment have, in recent years, heightened awareness of the burden of diabetes and aroused concern about the amount of health care resources that will be necessary to manage this disease effectively in the future. Examination of diabetes from the twin perspectives of economics and public health challenges basic notions of the health care tradition in the Western world: the real-world combination of finite resources and the growing need/demand for health services forces the consideration of limits in the provision of health care. The growing need to rationally allocate limited health care resources poses emotional, potentially divisive questions of science, politics, economics, and ethics that patients and physicians must each address.

Diabetes Mellitus and Cerebrovascular Disease: Prevalence of Carotid Artery Occlusive Disease and Associated Risk Factors in 482 Adult Diabetic Patients

The prevalence of carotid artery occlusive disease (CAOD) in a population of adults with diabetes mellitus was determined, and factors associated with its presence were identified. By oculoplethysmography and phonoangiography, 20% of the population studied had detectable CAOD. Univariate analyses revealed that patients with CAOD had a higher prevalence of retinopathy proteinuria, a slower mean conduction velocity in two of three nerves tested, and more atherosclerosis in the leg arteries. Furthermore, increased age, higher cholesterol, lower fasting insulin, higher systolic blood pressure, and less adiposity were associated with the presence of CAOD. Sex, race, type of diabetes (type I or II), duration of diabetes, and measures of glycemia were not related to CAOD. When 10 variables were analyzed by multivariate methods, higher systolic blood pressure, higher cholesterol, and reduced adiposity were found to be the combination most significantly related to CAOD.

Hypatia: Change, Limits, and Interconnectedness

To comprehend and, ideally, to manage the varied and dramatic changes occurring within the American health care system, especially as these changes impact not only the delivery of diabetes care but also scientific investigation of this important disorder, it may be helpful to step back from our daily activities, and use history, sociology, and literature i) to understand the present situation and 2) to identify future opportunities and strategies for the diabetes communities. I will address four questions:

Translation efforts in diabetes and pregnancy.

The Division of Diabetes Translation (DDT) of the National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control (CDC), has responsibility for improving the rapidity and extent of transfer of validated diabetes research findings into the practice of medicine. Three key words in this goal are rapidity, extent, and validated. The time between identification of important research findings and implementation in practice must be as short as possible, and all components of the health-care system must be aware of these findings. Furthermore, the research observations must be supported by the general scientific community. As an example, when evidence of the efficacy of photocoagulation was established, i.e., validated (1,2), this information needed to be quickly incorporated into practice, i.e., rapidity (3), by all components of the medical community, including primary-care practitioners and patients, i.e., extent (4).