Rizza, Robert A.

Both basal and postprandial pancreatic polypeptide (PP) concentrations were exaggerated twofold in lean NIDDM patients, whereas they were normal in lean IDDM and obese NIDDM patients who were hyperglycemic as a result of partial insulin withdrawal. Insulin infusion from an artificial endocrine pancreas, which resulted in fasting euglycemia and near-normoglycemia postprandially, had no effect on PP responses in any of the diabetic patients. No postprandial PP responses were observed in totally pancreatectomized (TPX) patients. Excessive basal and postprandial concentrations of PP in diabetes appear to be related to both leanness and residual beta cell function and, therefore, potential markers for lean NIDDM.

OBJECTIVE—Multiple daily insulin injection programs are commonly accompanied by considerable glycemic variation and hypoglycemia. We conducted a randomized crossover design clinical trial to compare glargine with ultralente insulin as a basal insulin in type 1 diabetes. RESEARCH DESIGN AND METHODS—To determine whether the use of glargine insulin as a basal insulin would result in a comparable HbA1c and less glycemic variation and hypoglycemia than ultralente insulin, 22 individuals (aged 44 ± 14 years [±SD], 55% men) with type 1 diabetes who were experienced with multiple daily insulin injections and had an HbA1c of <7.8% were randomized in a crossover design to receive either glargine or ultralente as the basal insulin for 4 months. Aspart insulin was used as the prandial insulin. Physicians providing insulin dose adjustment advice were masked to the type of basal insulin. RESULTS—Treatment with glargine resulted in lower mean HbA1c (6.82 ± 0.13 vs. 7.02 ± 0.13, difference: 0.2 ± 0.08, P = 0.026), less nocturnal variability (plasma glucose 49.06 ± 4.74 vs. 62.36 ± 5.21 mg/dl, P = 0.04), and less hypoglycemia (24.5 ± 2.99 vs. 31.3 ± 4.04 events, P = 0.05), primarily due to less daytime hypoglycemia (P = 0.002). On the other hand, serious hypoglycemia and average glucose concentration measured with continuous subcutaneous glucose monitoring did not differ. CONCLUSIONS—We conclude that while use of either ultralente or glargine as a basal insulin can result in excellent glycemic control, treatment with glargine is associated with slightly but significantly lower HbA1c and less nocturnal glycemic variability and hypoglycemia.

The objective of this study was to define the workforce needs for the specialty of Endocrinology, Diabetes, and Metabolism in the United States between 1999 and 2020. An interactive model of factors likely to influence the balance between the supply and demand of endocrinologists during the next 20 years was constructed. The model used data from a wide range of sources and was developed under the guidance of a panel of experts derived from sponsoring organizations of endocrinologists. We determined current and projected numbers and demographics of endocrinologists in the U.S. workforce and the anticipated balance between supply and demand from 1999 to 2020. There were 3,623 adult endocrinologists in the workforce in 1999, of which 2,389 (66%) were in office-based practice. Their median age was 49 years. Both total office visits and services performed by endocrinologists (particularly for diabetes) increased substantially during the 1990s. Waiting time for an initial appointment is presently longer for endocrinologists than for other physicians. Compared with a balanced, largely closed-staff health maintenance organization, the current national supply of endocrinologists is estimated to be 12% lower than demand. The number of endocrinologists entering the market has continuously fallen over the previous 5 years, from 200 in 1995 to 171 in 1999. Even if this downward trend were abruptly stopped, the model predicts that demand will exceed supply from now until 2020. While this gap narrows from 2000 to 2008 due to projected growth of managed care, it widens thereafter due to the aging of both the population and the endocrine workforce. Inclusion of other factors such as projected real income growth and increased prevalence of age-related endocrine disorders (e.g., diabetes and osteoporosis) further accentuates the deficit. If the number of endocrinologists entering the workforce remains at 1999 levels, demand will continue to exceed supply from now through 2020 for adult endocrinologists, and the gap will widen progressively from 2010 onward. The present analysis indicates that the number of endocrinologists entering the workforce will not be sufficient to meet future demand. These data suggest that steps should be taken to stop the ongoing decline in the number of endocrinologists in training and consideration should be given to actions designed to increase the number of endocrinologists in practice in the years ahead.

OBJECTIVE—The Mayo Health System Diabetes Translation Project sought to assess models of community-based diabetes care and use of a diabetes electronic management system (DEMS). Planned care is a redesigned model of chronic disease care that involves guideline implementation, support of self-management, and use of clinical information systems. RESEARCH DESIGN AND METHODS—We studied adult diabetic patients attending three primary care practice sites in Wisconsin and Minnesota. We implemented planned care at all sites and DEMS in the practice of 16 primary care providers. We assessed quality of diabetes care using standard indicators for 200 patients randomly selected from each site at baseline and at 24 months of implementation. We used multivariable analyses to estimate the association between planned care and DEMS and each quality indicator. RESULTS—Planned care was associated with improvements in measurement of HbA1c (odds ratio 7.0 [95% CI 4.2–11.6]), HDL cholesterol (5.6 [4.1–7.5]), and microalbuminuria (5.3 [3.5–8.0]), as well as the provision of tobacco advice (6.9 [4.7–10.1]), among other performance measures. DEMS use was associated with improvements in all indicators, including microalbuminuria (3.2 [1.9–5.2]), retinal examination (2.4 [1.5–3.9]), foot examinations (2.3 [1.2–4.4]), and self-management support (2.6 [1.7–3.8]). Although planned care was associated with improvements in metabolic control, we observed no additional metabolic benefit when providers used DEMS. CONCLUSIONS—Planned care was associated with improved performance and metabolic outcomes in primary care. DEMS use augmented the impact of planned care on performance outcomes but not on metabolic outcomes. Optimal identification of the best translation of evidence to diabetes practice will require longer follow-up or new care-delivery models.

OBJECTIVE The American Diabetes Association (ADA) has recommended that the fasting plasma glucose (FPG) level used to diagnose diabetes be changed from 7.8 mmol/l (the level recommended by the National Diabetes Data Group [NDDG] in 1979) to 7.0 mmol/l. We examined the impact of this change on rates of progression to overt diabetes from different levels of FPG. RESEARCH DESIGN AND METHODS Using the laboratory database of Mayo Clinic, we assembled a cohort of 8,098 nondiabetic Olmsted County residents 40 years of age or older on 1 July 1983. Subjects were followed for a median of 9 years. RESULTS Among 7,567 individuals with follow-up FPG data, 778 (10.3%) progressed to ADA diabetes and 513 (6.8%; P < 0.0001) progressed to NDDG diabetes. The risk of developing ADA diabetes was 7, 19, and 39% for individuals with initial FPG values in the ranges of <5.6, 5.6–6.0, and 6.1–6.9 mmol/l, respectively. For progression to NDDG diabetes, the respective risks were 3, 11, and 25%. A clear gradient of risk was observed within the “normal” range of FPG (<5.6 mmol/l). Among the 793 individuals who developed ADA diabetes, 222 (29%) developed NDDG diabetes simultaneously and 291 (37%) developed NDDG diabetes later. In all FPG subgroups, progression to ADA diabetes occurred ∼7 years sooner than progression to NDDG diabetes. CONCLUSIONS The baseline level of FPG is a major predictor of an individual's risk of developing diabetes. The proposed change in the diagnostic criteria for diabetes will lead to earlier diagnosis among individuals who are destined to develop the disease.

OBJECTIVE To compare the compliance with diabetes care performance indicators by diabetes specialists using a diabetes electronic management system (DEMS) and by those using the traditional paper medical record. RESEARCH DESIGN AND METHODS A DEMS has been gradually introduced into our subspecialty practice for diabetes care. To assess the value of this DEMS as a disease management tool, we completed a retrospective review of the medical records of 82 randomly selected patients attending a subspecialty diabetes clinic (DC) during the first quarter of 1996. Eligible patients were defined by the suggested criteria from the American Diabetes Association Provider Recognition Program. During the first quarter of 1996, ∼ one half of the providers began using the DEMS for some but not all of their patient encounters. Neither abstractors nor providers were aware of the intent to examine performance in relationship to use of the DEMS. RESULTS Several measures were positively influenced when providers used the DEMS. The number of foot examinations, the number of blood pressure readings, and a weighted criterion score were greater (P < 0.01) for providers using the DEMS. There was evidence, although not statistically significant, for lower mean diastolic blood pressures (P = 0.043) in patients and for number of glycated hemoglobins documented (P = 0.018) by users of the DEMS. CONCLUSIONS Performance and documentation of the process of care for patients with diabetes in a subspecialty clinic are greater with the use of a DEMS than with the traditional paper record.

OBJECTIVE To evaluate both the concordance in the classification of diabetes by clinical and C-peptide criteria and, prospectively, the consistency of the classification by C-peptide. RESEARCH DESIGN AND METHODS Individuals with diabetes who were enlisted in the prospective epidemiological study of diabetic neuropathy (Rochester Diabetic Neuropathy Study [RDNS]) were classified clinically by National Diabetes Data Group (NDDG) criteria to IDDM and NIDDM at entry to the study. In addition, C-peptide response to 1 mg glucagon was measured at entry for the classification to IDDM (basal C-peptide, < 0.17 pmol/ml; increment above basal, < 0.07 pmol/ml) and NIDDM (all other responses) and for concordance with the clinical classification made. The consistency of the C-peptide response was assessed every 2 years for up to 8 years. RESULTS Among 346 individuals with diabetes, 84 were classified as IDDM and 262 as NIDDM by clinical algorithm. COncordance with the C-peptide response occurred in 89% of the patients and remained consistent during 8 years of follow-up. Among the 37 patients with discordant clinical and C-peptide classification, those considered clinically to have NIDDM had a consistent IDDM C-peptide response during follow-up, and most of those considered to have IDDM clinically eventually showed an IDDM C-peptide response during follow-up. CONCLUSIONS Clinical criteria for the classification of diabetes are highly correlated with the assessment of insulin secretory reserve. A small number of individuals considered to have NIDDM clinically or by C-peptide have or develop an IDDM peptide response.

OBJECTIVE Despite widespread acceptance of continuous insulin infusion (CII) over bolus insulin injection (BII) for treatment of diabetic ketoacidosis (DKA), there are no population-based studies demonstrating whether CII has resulted in lower morbidity and mortality. RESEARCH DESIGN AND METHODS We addressed this issue using a provider-linked database and retrospectively reviewing the complete medical records of all incidence cases of diabetes among Rochester, Minnesota, residents from 1950 to 1989 with a discharge diagnosis of DKA. This population-based study describes the consequences of the widespread change in treatment modality outside the confines of a controlled clinical trial. RESULTS Among the diabetes incident cohort, there were 59 subjects with confirmed first episodes of DKA during 1950-1992; 29 of 30 subjects treated with BII occurred before 1970. All 29 CII cases occurred between 1976 and 1992. Sex, etiology, diabetes duration, and age at DKA were similar for the two groups. The proportion of obese individuals (BII = 2/28, CII = 8/21; P = 0.01) differed between groups. The CII group exhibited higher glucose values (BII = 24.9 ± 8.5 mmol/l, CII = 37.1 ± 15.1 mmol/l; P = 0.002) and lower bicarbonate values (BII = 7.7 ± 3.0 nmol/l, CII = 6.2 ± 2.9 nmol/l; P = 0.04) upon admission. The mean quantity of insulin administered was higher in the BII group than in the CII group (179 ± 140 and 99 ± 70 U, P < 0.006). The outcome of hypoglycemia occurred more frequently in the BII group than in the CII group (BII = 8/30, CII = 1/29; P = 0.03). The proportion with hypokalemia, neurological deficit, myocardial arrhythmia, or mortality did not differ significantly between groups. CONCLUSIONS Our findings suggest the introduction of CII was accompanied by a decreased incidence of hypoglycemia.

OBJECTIVE To determine the role of growth hormone (GH) in the development of diabetic retinopathy. RESEARCH DESIGN AND METHODS Medical records of 1,423 patients who had undergone insulin tolerance tests (1976–1991) at the Mayo Clinic were examined, and diabetic subjects were identified as either GH-deficient (GH increment after hypoglycemia <5 μg/L and peak <10 μg/L) or GH-suificient. Prevalence of retinopathy was determined in these cases and in a cohort group of diabetic subjects selected to match the GH-deficient cases. These control patients (32 cases) were selected from medical records of individuals who had received medical care at Mayo during the same interval but who had not undergone insulin tolerance testing. RESULTS Twenty-four patients with diabetes were identified, of whom 16 were GH-deficient and 8 GH-sufficient. Despite comparable age, duration of diabetes, and metabolic control, the prevalence of diabetic retinopathy in the GH-deficient group (2 of 16; 12.5%) was less (P < 0.05) than that observed in the GH-sufficient group (5 of 8; 62.5%). Prevalence in the GH-deficient group also was lower than that observed in the cohort control group (15 of 32, 47%). CONCLUSIONS These data strongly suggest that GH contributes to the development of diabetic retinopathy in humans.