Person: Nathan, David
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Nathan
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Nathan, David
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Publication A computational model of 1,5‐AG dynamics during pregnancy(John Wiley and Sons Inc., 2017) Zekavat, Seyedeh M.; Butkovich, Slava; Young, Grace; Nathan, David; Petrasek, DannyAbstract The importance of 1,5‐anhydroglucitol (1,5‐AG) as an intermediate biomarker for diabetic pregnancy is multi‐fold: (1) it serves as a reliable indicator of moderate‐level glycemic control, especially during early gestation; (2) it has been associated with increased risk of diabetes, independent of HbA1c and fasting glucose; and (3) it is an independent risk factor for the development of eclampsia during pregnancy. However, the clinical use of this biomarker during pregnancy has been underutilized due to physiological changes in glomerular filtration rate, plasma volume, and other hemodynamic parameters which have been hypothesized to bias gestational serum 1,5‐AG concentrations. Here, we develop an in‐silico model of gestational 1,5‐AG by combining pre‐existing physiological data in the literature with a two‐compartment mathematical model, building off of a previous kinetic model described by Stickle and Turk (1997) Am. J. Physiol., 273, E821. Our model quantitatively characterizes how renal and hemodynamic factors impact measured 1,5‐AG during normal pregnancy and during pregnancy with gestational diabetes and diabetes mellitus. During both normal and diabetic pregnancy, we find that a simple two‐compartment model of 1,5‐AG kinetics, with all parameters but reabsorption fraction adjusted for time in pregnancy, efficiently models 1,5‐AG kinetics throughout the first two trimesters. Allowing reabsorption fraction to decrease after 25 weeks permits parameters closer to expected physiological values during the last trimester. Our quantitative model of 1,5‐AG confirms the involvement of hypothesized renal and hemodynamic mechanisms during pregnancy, clarifying the expected trends in 1,5‐AG to aid clinical interpretation. Further research and data may elucidate biological changes during the third trimester that account for the drop in 1,5‐AG concentrations, and clarify physiological differences between diabetes subtypes during pregnancy.Publication Clinical Outcomes of Metabolic Surgery: Microvascular and Macrovascular Complications(American Diabetes Association, 2016) Adams, Ted D.; Arterburn, David E.; Nathan, David; Eckel, Robert H.Understanding of the long-term clinical outcomes associated with bariatric surgery has recently been advanced. Research related to the sequelae of diabetes—in particular, long-term microvascular and macrovascular complications—in patients who undergo weight-loss surgery is imperative to this pursuit. While numerous randomized control trials have assessed glucose control with bariatric surgery compared with intensive medical therapy, bariatric surgery outcome data relating to microvascular and macrovascular complications have been limited to observational studies and nonrandomized clinical trials. As a result, whether bariatric surgery is associated with a long-term reduction in microvascular and macrovascular complications when compared with current intensive glycemic control therapy cannot be determined because the evidence is insufficient. However, the consistent salutary effects of bariatric surgery on diabetes remission and glycemic improvement support the opportunity (and need) to conduct high-quality studies of bariatric surgery versus intensive glucose control. This review provides relevant background information related to the treatment of diabetes, hyperglycemia, and long-term complications; reports clinical findings (to date) with bariatric surgery; and identifies ongoing research focusing on long-term vascular outcomes associated with bariatric surgery.Publication Association of Glycemic Variability in Type 1 Diabetes With Progression of Microvascular Outcomes in the Diabetes Control and Complications Trial(American Diabetes Association, 2017) Lachin, John M.; Bebu, Ionut; Bergenstal, Richard M.; Pop-Busui, Rodica; Service, F. John; Zinman, Bernard; Nathan, DavidOBJECTIVE The Diabetes Control and Complications Trial (DCCT) demonstrated the beneficial effects of intensive versus conventional therapy on the development and progression of microvascular complications of type 1 diabetes. These beneficial effects were almost completely explained by the difference between groups in the levels of HbA1c, which in turn were associated with the risk of these complications. We assessed the association of glucose variability within and between quarterly 7-point glucose profiles with the development and progression of retinopathy, nephropathy, and cardiovascular autonomic neuropathy during the DCCT. RESEARCH DESIGN AND METHODS Measures of variability included the within-day and updated mean (over time) of the SD, mean amplitude of glycemic excursions (MAGE), and M-value, and the longitudinal within-day, between-day, and total variances. Imputation methods filled in the 16.3% of expected glucose values that were missing. RESULTS Cox proportional hazards models assessed the association of each measure of glycemic variation, as a time-dependent covariate, with the risk of retinopathy and nephropathy, and a longitudinal logistic regression model did likewise for cardiovascular autonomic neuropathy. Adjusted for mean blood glucose, no measure of within-day variability was associated with any outcome. Only the longitudinal mean M-value (over time) was significantly associated with microalbuminuria when adjusted for the longitudinal mean blood glucose and corrected for multiple tests using the Holm procedure. CONCLUSIONS Overall, within-day glycemic variability, as determined from quarterly glucose profiles, does not play an apparent role in the development of microvascular complications beyond the influence of the mean glucose.Publication Pretreatment, Psychological, and Behavioral Predictors of Weight Outcomes Among Lifestyle Intervention Participants in the Diabetes Prevention Program (DPP)(American Diabetes Association, 2013) Delahanty, Linda; Peyrot, Mark; Shrader, Peter J.; Williamson, Donald A.; Meigs, James; Nathan, DavidOBJECTIVE To identify the most important pretreatment characteristics and changes in psychological and behavioral factors that predict weight outcomes in the Diabetes Prevention Program (DPP). RESEARCH DESIGN AND METHODS Approximately 25% of DPP lifestyle intervention participants (n = 274) completed questionnaires to assess weight history and psychological and behavioral factors at baseline and 6 months after completion of the 16-session core curriculum. The change in variables from baseline to 6 months was assessed with t tests. Multivariate models using hierarchical logistic regression assessed the association of weight outcomes at end of study with each demographic, weight loss history, psychological, and behavioral factor. RESULTS At end of study, 40.5% had achieved the DPP 7% weight loss goal. Several baseline measures (older age, race, older age when first overweight, fewer self-implemented weight loss attempts, greater exercise self-efficacy, greater dietary restraint, fewer fat-related dietary behaviors, more sedentary activity level) were independent predictors of successful end-of-study weight loss with the DPP lifestyle program. The DPP core curriculum resulted in significant improvements in many psychological and behavioral targets. Changes in low-fat diet self-efficacy and dietary restraint skills predicted better long-term weight loss, and the association of low-fat diet self-efficacy with weight outcomes was explained by dietary behaviors. CONCLUSIONS Health care providers who translate the DPP lifestyle intervention should be aware of pretreatment characteristics that may hamper or enhance weight loss, consider prioritizing strategies to improve low-fat diet self-efficacy and dietary restraint skills, and examine whether taking these actions improves weight loss outcomes.Publication A Comparative Effectiveness Analysis of Three Continuous Glucose Monitors(American Diabetes Association, 2013) Damiano, Edward R.; El-Khatib, Firas H.; Zheng, Hui; Nathan, David; Russell, StevenOBJECTIVE To compare three continuous glucose monitoring (CGM) devices in subjects with type 1 diabetes under closed-loop blood glucose (BG) control. RESEARCH DESIGN AND METHODS Six subjects with type 1 diabetes (age 52 ± 14 years, diabetes duration 32 ± 14 years) each participated in two 51-h closed-loop BG control experiments in the hospital. Venous plasma glucose (PG) measurements (GlucoScout, International Biomedical) obtained every 15 min (2,360 values) were paired in time with corresponding CGM glucose (CGMG) measurements obtained from three CGM devices, the Navigator (Abbott Diabetes Care), the Seven Plus (DexCom), and the Guardian (Medtronic), worn simultaneously by each subject. Errors in paired PG–CGMG measurements and data reporting percentages were obtained for each CGM device. RESULTS The Navigator had the best overall accuracy, with an aggregate mean absolute relative difference (MARD) of all paired points of 11.8 ± 11.1% and an average MARD across all 12 experiments of 11.8 ± 3.8%. The Seven Plus and Guardian produced aggregate MARDs of all paired points of 16.5 ± 17.8% and 20.3 ± 18.0%, respectively, and average MARDs across all 12 experiments of 16.5 ± 6.7% and 20.2 ± 6.8%, respectively. Data reporting percentages, a measure of reliability, were 76% for the Seven Plus and nearly 100% for the Navigator and Guardian. CONCLUSIONS A comprehensive head-to-head-to-head comparison of three CGM devices for BG values from 36 to 563 mg/dL revealed marked differences in performance characteristics that include accuracy, precision, and reliability. The Navigator outperformed the other two in these areas.Publication Effect of Glycemic Treatment and Microvascular Complications on Menopause in Women With Type 1 Diabetes in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) Cohort(American Diabetes Association, 2014) Kim, Catherine; Cleary, Patricia A.; Cowie, Catherine C.; Braffett, Barbara H.; Dunn, Rodney L.; Larkin, Mary; Gatcomb, Patricia M.; Wessells, Hunter B.; Nathan, David; Sarma, Aruna V.OBJECTIVE We examined the impact of intensive versus conventional diabetes treatment upon menopause among women with type 1 diabetes in the Diabetes Control and Complications Trial (DCCT), a randomized controlled trial of intensive diabetes treatment, and its observational follow-up, the Epidemiology of Diabetes Interventions and Complications (EDIC) study. RESEARCH DESIGN AND METHODS In a secondary analysis of women in the DCCT/EDIC (n = 657), outcomes were the cumulative incidences of natural menopause and surgical menopause. Cox regression analyses were used to examine associations with treatment group, time-varying estimates of hemoglobin A1c (HbA1c), insulin dosage, BMI, and microvascular complications (retinopathy, nephropathy, and neuropathy). RESULTS By EDIC year 18, after an average of 28 years of follow-up, 240 (38%) women had experienced natural menopause and 115 (18%) women had experienced surgical menopause. Age at natural menopause was similar in the intensive versus conventional groups (49.9 vs. 49.0 years; P = 0.28), and age at surgical menopause was similar in the intensive versus conventional groups (40.8 vs. 42.0 years; P = 0.31). In multivariable models, treatment group, HbA1c, and microvascular complications were not associated with risk of natural or surgical menopause. Each 10 unit/day increase in insulin dosage decreased risk of natural menopause (hazard ratio [HR] 0.91, 95% CI 0.75–0.98) and each kg/m2 increase in BMI increased risk of surgical menopause (HR 1.08, 95% CI 1.00–1.16). CONCLUSIONS In the DCCT/EDIC, intensive versus conventional treatment group and HbA1c level were not associated with menopause risk. Greater insulin dose was associated with lower menopause risk.Publication Musculoskeletal Complications in Type 1 Diabetes(American Diabetes Association, 2014) Larkin, Mary; Barnie, Annette; Braffett, Barbara H.; Cleary, Patricia A.; Diminick, Lisa; Harth, Judy; Gatcomb, Patricia; Golden, Ellen; Lipps, Janie; Lorenzi, Gayle; Mahony, Carol; Nathan, DavidOBJECTIVE The development of periarticular thickening of skin on the hands and limited joint mobility (cheiroarthropathy) is associated with diabetes and can lead to significant disability. The objective of this study was to describe the prevalence of cheiroarthropathy in the well-characterized Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) cohort and examine associated risk factors, microvascular complications, and the effect of former DCCT therapy (intensive [INT] vs. conventional [CONV]) on its development. RESEARCH DESIGN AND METHODS This cross-sectional analysis was performed in 1,217 participants (95% of the active cohort) in EDIC years 18/19 after an average of 24 years of follow-up. Cheiroarthropathy—defined as the presence of any one of the following: adhesive capsulitis, carpal tunnel syndrome, flexor tenosynovitis, Dupuytren's contracture, or a positive prayer sign—was assessed using a targeted medical history and standardized physical examination. A self-administered questionnaire (Disabilities of the Arm, Shoulder and Hand [DASH]) assessed functional disability. RESULTS Cheiroarthropathy was present in 66% of subjects (64% of the INT group and 68% of the CONV group; P = 0.1640) and was associated with age, sex, diabetes duration, skin intrinsic fluorescence, HbA1c, neuropathy, and retinopathy (P < 0.005 for each). DASH functional disability scores were worse among subjects with cheiroarthropathy (P < 0.0001). CONCLUSIONS Cheiroarthropathy is common in people with type 1 diabetes of long duration (∼30 years) and is related to longer duration and higher levels of glycemia. Clinicians should include cheiroarthropathy in their routine history and physical examination of patients with type 1 diabetes because it causes clinically significant functional disability.Publication Changes in Body Composition over Eight Years in a Randomized Trial of a Lifestyle Intervention: The Look AHEAD Study(2014) Pownall, Henry J.; Bray, George A.; Wagenknecht, Lynne E.; Walkup, Michael P.; Heshka, Stanley; Hubbard, Van S.; Hill, James; Kahn, Steven E.; Nathan, David; Schwartz, Anne V.; Johnson, Karen C.Objective: To determine the effects of an intensive lifestyle intervention vs. a comparison group on body composition in obese or overweight persons with type 2 diabetes at baseline and at 1, 4, and 8 years. Design and Methods Body composition was measured by dual energy X-ray absorptiometry in a subset of 1019 Look Ahead study volunteers randomized to intervention or comparison groups. The intervention was designed to achieve and maintain ≥7% weight loss through increased physical activity and reduced caloric intake. The comparison group received social support and diabetes education. Results: At 1 year, the intervention group lost fat (5.6 ± 0.2 kg) and lean mass (2.3 ± 0.1 kg) but regained fat (~100%), and lost lean mass between years 1 and 8. Between baseline and year-8, weight-loss was greater in intervention vs. comparison groups (4.0 ± 0.4 vs. 2.3 ± 0.4 kg); comparison group weight-loss was mostly lean mass (2.1 ± 0.17 kg). Fat mass in the intervention group was lower than that of the comparison group at all post-baseline time points. Conclusions: Reduced FM may place the intervention group at a lower risk of obesity-linked sequelae, a hypothesis that can be tested by future studies of this cohort. Trial Registration ClinicalTrials.gov Identifier: NCT00017953Publication Empirically Establishing Blood Glucose Targets to Achieve HbA1c Goals(American Diabetes Association, 2014) Wei, Nancy; Zheng, Hui; Nathan, DavidOBJECTIVE To determine the average fasting, postprandial, and bedtime self-monitored blood glucose (SMBG) concentrations associated with specified HbA1c levels using data from the A1c-Derived Average Glucose (ADAG) study. RESEARCH DESIGN AND METHODS The ADAG study was a multicenter observational study that used continuous glucose monitoring and SMBG testing to determine the relationship between mean average glucose and HbA1c. We used the SMBG data from 470 of the ADAG study participants (237 with type 1 diabetes and 147 with type 2 diabetes) to determine the average fasting, premeal, 90-min postmeal, and bedtime blood glucose (BG) for predefined target HbA1c groups between 5.5 and 8.5% (37–69 mmol/mol). t Tests were used to compare mean BG values between type 1 and type 2 diabetes groups. RESULTS The average fasting BG needed to achieve predefined HbA1c target levels of 5.5–6.49% (37–47 mmol/mol), 6.5–6.99% (48–52 mmol/mol), 7.0–7.49% (52–58 mmol/mol), 7.5–7.99% (58–64 mmol/mol), and 8.0–8.5% (64–69 mmol/mol) were 122 mg/dL with 95% CI 117–127, 142 mg/dL (135–150), 152 mg/dL (143–162), 167 mg/dL (157–177), and 178 mg/dL (164–192), respectively. Postmeal BG to achieve the HbA1c level of 6.5–6.99% (48–52 mmol/mol) and 7.0–7.49% (52–58 mmol/mol) were 139 mg/dL (134–144) and 152 mg/dL (147–157), respectively. Bedtime BG was 153 mg/dL (145–161) and 177 mg/dL (166–188), respectively. CONCLUSIONS We have determined the average BG at premeal, postmeal, and bedtime to achieve a variety of HbA1c targets. These results, based on empirical data, will help patients and providers set realistic day-to-day SMBG targets to achieve individualized HbA1c goals.Publication Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus(American Diabetes Association, 2011) Sacks, David Barry; Arnold, Mark; Bakris, George L.; Bruns, David E.; Horvath, Andrea Rita; Kirkman, M. Sue; Lernmark, Ake; Metzger, Boyd E.; Nathan, DavidBackground: Multiple laboratory tests are used to diagnose and manage patients with diabetes mellitus. The quality of the scientific evidence supporting the use of these tests varies substantially. Approach: An expert committee compiled evidence-based recommendations for the use of laboratory testing for patients with diabetes. A new system was developed to grade the overall quality of the evidence and the strength of the recommendations. Draft guidelines were posted on the Internet and presented at the 2007 Arnold O. Beckman Conference. The document was modified in response to oral and written comments, and a revised draft was posted in 2010 and again modified in response to written comments. The National Academy of Clinical Biochemistry and the Evidence-Based Laboratory Medicine Committee of the American Association for Clinical Chemistry jointly reviewed the guidelines, which were accepted after revisions by the Professional Practice Committee and subsequently approved by the Executive Committee of the American Diabetes Association. Content: In addition to long-standing criteria based on measurement of plasma glucose, diabetes can be diagnosed by demonstrating increased blood hemoglobin A\(_{1c}\) (HbA\(_{1c}\)) concentrations. Monitoring of glycemic control is performed by self-monitoring of plasma or blood glucose with meters and by laboratory analysis of HbA\(_{1c}\). The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of autoantibodies, urine albumin, insulin, proinsulin, C-peptide, and other analytes are addressed. Summary: The guidelines provide specific recommendations that are based on published data or derived from expert consensus. Several analytes have minimal clinical value at present, and their measurement is not recommended.