Leibson, Cynthia L.

OBJECTIVE—The aims of this study were to provide estimates of 1) the risk of mortality for individuals with both diabetes and peripheral arterial disease (PAD) relative to that for individuals with either condition alone and 2) the association between PAD progression and mortality for individuals with diabetes, PAD, and both conditions. RESEARCH DESIGN AND METHODS—This longitudinal cohort study was conducted in Rochester, Minnesota. Local residents age 50–70 years with a prior diagnosis of PAD and/or diabetes were identified from the Mayo Clinic diagnostic registry and invited to a baseline examination (1977–1978). Those who met inclusion criteria were assessed for PAD progression at 2 and 4 years and followed for vital status through 31 December 1999. RESULTS—The numbers who met criteria for PAD, diabetes, and both conditions at baseline were 149, 238, and 186, respectively. Within each group, observed survival was less than expected (P < 0.001). The adjusted risk of death for both conditions was 2.2 times that for PAD alone. Among the 449 who returned at 4 years, the risk of subsequent death was greater for those whose PAD had progressed; among individuals with diabetes alone at baseline, 100% (17 of 17) who met criteria for PAD progression were dead by 31 December 1999 compared with 62% (111 of 178) of those who had not met criteria (adjusted relative hazard 2.29 [95% CI 1.30–4.02], P = 0.004). The increased mortality associated with PAD progression was significant only for individuals with diabetes (alone or with PAD). CONCLUSIONS—Diabetes is a risk factor for both PAD and PAD-associated mortality, emphasizing the critical need to detect and monitor PAD in diabetic patients.

OBJECTIVE—To examine the influence of obesity and prevention of weight gain on the incidence of type 2 diabetes. RESEARCH DESIGN AND METHODS—We examined participants in the San Antonio Heart Study, a prospective population-based study of Mexican Americans and non-Hispanic whites residing in San Antonio, Texas. BMI was stratified into four categories: normal (<25 kg/m2), overweight (≥25 kg/m2 and <30 kg/m2), obese (≥30 kg/m2 and <35 kg/m2), and very obese (≥35 kg/m2). The number and proportion of incident cases prevented by targeting each BMI category were estimated. In addition, we calculated the decrease in risk of developing type 2 diabetes associated with weight gain prevention across both the BMI and age spectra. RESULTS—Preventing normal individuals from becoming overweight would result in the greatest reduction in incidence of type 2 diabetes. This would result in a 62 and 74% reduction in the incidence of type 2 diabetes in Mexican Americans and non-Hispanic whites, respectively. Preventing the entire population from gaining, on average, 1 BMI unit would result in a reduction in incidence of type 2 diabetes of 12.4 and 13.0% in Mexican Americans and non-Hispanic whites, respectively. CONCLUSIONS—The majority of cases of type 2 diabetes were in individuals who were overweight or mildly obese with a family history of type 2 diabetes. Public health resources should be directed toward the prevention of weight gain among normal and overweight individuals in order to prevent the maximum number of cases of type 2 diabetes.

OBJECTIVE—Increasing obesity within the general population has been accompanied by rising rates of diabetes. The extent to which obesity has increased among people with diabetes is unknown, as are the potential consequences for diabetes outcomes. RESEARCH DESIGN AND METHODS—Community medical records (hospital and ambulatory) of all Rochester, Minnesota, residents aged ≥30 years who first met standardized research criteria for diabetes from 1970 to 1989 (n = 1,306) were reviewed to obtain data on BMI and related characteristics as of the diabetes identification date (±3 months). Vital status as of 31 December 1999 and date of death for those who died were obtained from medical records, State of Minnesota death tapes, and active follow-up. RESULTS—As of the identification date, data on BMI were available for 1,290 cases. Of the 272 who first met diabetes criteria in 1970–1974, 33% were obese (BMI ≥30), including 5% who were extremely obese (BMI ≥40). These proportions increased to 49% (P < 0.001) and 9% (P = 0.012), respectively, for the 426 residents who first met diabetes criteria in 1985–1989. BMI increased significantly with increasing calendar year of diabetes identification in multivariable regression analysis. Analysis of survival revealed an increased hazard of mortality for BMI ≥41, relative to BMI of 23–25 (hazard ratio 1.60, 95% CI 1.09–2.34, P = 0.016). CONCLUSIONS—The prevalence of obesity and extreme obesity among individuals at the time they first met criteria for diabetes has increased over time. This is disturbing in light of the finding that diabetic individuals who are extremely obese are at increased risk of mortality compared with their nonobese diabetic counterparts.

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 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.