The Diabetes Prevention Program is a randomized clinical trial testing strategies to prevent or delay the development of type 2 diabetes in high-risk individuals with elevated fasting plasma glucose concentrations and impaired glucose tolerance. The 27 clinical centers in the U.S. are recruiting at least 3,000 participants of both sexes, ~50% of whom are minority patients and 20% of whom are ≥65 years old, to be assigned at random to one of three intervention groups: an intensive lifestyle intervention focusing on a healthy diet and exercise and two masked medication treatment groupsmetformin or placebo-combined with standard diet and exercise recommendations. Participants are being recruited during a 2 2/3-year period, and all will be followed for an additional 3 1/3 to 5 years after the close of recruitment to a common closing date in 2002. The primary outcome is the development of diabetes, diagnosed by fasting or post-challenge plasma glucose concentrations meeting the 1997 American Diabetes Association criteria. The 3,000 participants will provide 90% power to detect a 33% reduction in an expected diabetes incidence rate of at least 6.5% per year in the placebo group. Secondary outcomes include cardiovascular disease and its risk factors; changes in glycemia, β-cell function, insulin sensitivity, obesity, diet, physical activity, and health-related quality of life; and occurrence of adverse events. A fourth treatment group-troglilazone combined with standard diet and exercise recommendations-was included initially but discontinued because of the liver toxicity of the drug. This randomized clinical trial will test the possibility of preventing or delaying the onset of type 2 diabetes in individuals at high risk. AbbreviationsADA, American Diabetes Association; DPP, Diabetes Prevention Program; FPG, fasting plasma glucose; IGT, impaired glucose tolerance; NIDDK, National Institute of Diabetes and Digestive and Kidney Diseases; OGTT, oral glucose tolerance test; WHO, World Health Organization Type 2 diabetes is a common chronic disease affecting an estimated 12% of 40-to 74-yearold people in the U.S. (1). It is a major cause of premature mortality and morbidity due to cardiovascular, renal, ophthalmic, and neurologic diseases. Although treatment of type 2 diabetes can improve hyperglycemia, normalization of glycemia and glycohemoglobin is rarely achieved or maintained. Furthermore, macro-vascular disease and its risk factors are often already present in individuals at high risk of developing type 2 diabetes (2). Therefore, a policy RESEARCH GOALS PrimaryThe primary research goal is a comparison of the efficacy and safety of each of three interventions (an intensive lifestyle intervention or standard lifestyle recommendations combined with metformin or placebo) in preventing or delaying the development of diabetes. Diabetes is diagnosed by fasting plasma glucose (FPG) or glucose tolerance testing according to the 1997 American Diabetes Association (ADA) criteria (1). SecondarySecondary research goals i...
OBJECTIVE -Although subjects with diabetes have increased risk for cardiovascular disease (CVD), the evolution of this increased risk as pre-diabetic individuals progress to diabetes is not understood. This study examines the longitudinal relationship between selected CVD risk factors (blood pressure, triglycerides, HDL and LDL cholesterol, and LDL peak particle density [PPD]) and glycemia in the three treatment groups of the Diabetes Prevention Program. RESEARCH DESIGN AND METHODS-A total of 3,234 participants with impaired glucose tolerance (IGT) were followed for a mean of 3.2 years after randomization to intensive lifestyle intervention (ILS), metformin, or placebo. Using repeated-measures models, adjusted mean levels of risk factors were estimated for an annual change in glycemic status. Tests were also conducted to assess the risk factor trends with improvement or worsening of glycemic status.RESULTS -CVD risk factor values and changes from baseline became more unfavorable as glucose tolerance status deteriorated but improved with reversion to normal glucose tolerance (NGT), especially in the ILS intervention group (trend test P Ͻ 0.001 for all risk factors except for LDL PPD [P ϭ 0.02] in ILS and HDL cholesterol [P ϭ 0.02] in placebo). Although there were few significant differences in the transition from IGT to diabetes, there were strong relationships between risk factors and continuous measures of glycemia.CONCLUSIONS -Progression from IGT to diabetes is associated with mild deterioration, whereas reversion to NGT is associated with improvement in risk factors. Early intervention with ILS, but less so with metformin, in participants at high risk for diabetes improves the cardiovascular risk and glucose tolerance profile simultaneously. Diabetes Care 32:726-732, 2009
A B S T R A C T To determine if pancreatic glucoregulatory hqrmones can be implicated in the glucose fall of pregnancy, we have measured plasma immunoreactive insulin and glucagon (IRI and IRG) in rats. Fed rats in midgestation show a rise in IRI without a corresponding increase in IRG. In late gestation, IRG rises significantly, but only enough to keep pace with a further rise in IRI. On a molar basis, IRI remains the predominant hormone despite a marked fall in blood glucose. After a 48-h fast IRI falls to comparably low levels in pregnant and virgin rats. A small rise in IRG is seen in virgin but not in pregnant rats despite frank hypoglycemia in the latter. Thus, IRG secretion in pregnancy is diminished relative to IRI in the fed state and fails to increase in the fasted state despite the stimulus of a lower glucose in both instances.To evaluate IRG secretory reserve, the IRG response to i.v. alanine was assessed in late gestation. In fed rats a greater IRG increase is seen in pregnancy; after fasting no difference is seen between pregnant and virgin rats. These results preclude an absolute deficiency in glucagon secretion. Pancreas hormone stores were also measured in an effort to explain the altered secretory state. We find reciprocal changes in IRI and IRG content favoring IRG in midgestation and IRI in late gestation. Thus, pancreas hormone storage is altered in pregnancy but does not account for the changes in hormone secretion. Rather, pregnancy exerts
This report describes the clinically significant design features of a variable rate implantable insulin infusion pump, the Programmable Implantable Medication System (PIMS), and its function in pre-clinical trials. PIMS has a number of unique features, including a solenoid, pulsatile pump design requiring minimal power (less than 15 microwatts) and a less-than-atmospheric pressure reservoir. Two-way communication is accomplished by radiotelemetry. The implanted device stores programs, and records its own hourly history of insulin delivery. Limits are set on total insulin delivery over time. Basal rates are adjustable, and patterned prandial insulin delivery curves can be programmed. Initial trials (3.1 dog-years) identified four problems which were corrected prior to final pre-clinical trials: microcracks in the diaphragm, a valve-seating leak, electronic failure of prototype microchips, and insulin aggregation. Sixteen dog-years of final pre-clinical trials with a single system design demonstrated that 5 pumps were still working continuously after up to 3.75 years (mean 3.3 years) without mechanical or electronic pump failure. The longest interval between reservoir refills was 5 months. Remaining potential causes of flow stoppage, however, include blockage of the peritoneal catheter by omentum (which occurred once), and air lock (which occurred two times).
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