Browsing by Author "Kirkman, M. Sue"

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    The linearized disposition index augments understanding of treatment effects in diabetes
    (American Physiological Society, 2021) Kile, Amanda J.; Hanna, Clarissa; Hannon, Tamara S.; Kirkman, M. Sue; Considine, Robert V.; Patel, Yash; Mather, Kieren J.; Medicine, School of Medicine
    The disposition index, calculated by multiplying measures of insulin secretion and insulin sensitivity, is widely applied as a sensitivity-adjusted measure of insulin secretion. We have recently shown that linearizing the underlying relationship uniquely permits identification of terms relating to maximal insulin secretion capacity and the secretion-coupling relationship, with both terms separately contributing to differences in the secretion-sensitivity relationship across gradations of glycemia. Here, we demonstrate the application of this linearized equation to the evaluation of treatment-induced changes in the insulin secretion-sensitivity relationship. We applied a combination of repeated-measures multivariate linear regression (evaluating treatment-induced changes in the joint relationship of insulin sensitivity and secretion) plus mixed-model repeated measures (evaluating treatment effects on maximal secretion capacity and on the secretion-sensitivity coupling slope) and compared against a usual application of the disposition index calculated from the same measurements. This novel approach allows a more informative description of treatment-induced changes compared with the usual disposition index, including isolating the source of change within the mutually adjusted relationship and identifying treatment-induced changes in the secretion-sensitivity coupling slope and in maximal insulin secretion. Application of this linearized approach provides an expanded understanding of treatment-induced changes in the insulin sensitivity-secretion relationship. NEW & NOTEWORTHY: The linearized insulin secretion-sensitivity relationship allows separate evaluation of the secretion-sensitivity slope and of maximal insulin secretion. Here, we demonstrate the application of this methodology to the evaluation of clinical trial data, showing that it provides an expanded understanding of treatment-induced changes compared with the disposition index.
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    Predictors of glycemic worsening in the next year in adults with screen-detected type 2 diabetes
    (medRxiv, 2024-04-27) Schneider Aguirre, Rebecca; Hannon, Tamara S.; Considine, Robert V.; Patel, Yash; Kirkman, M. Sue; Mather, Kieren J.; Pediatrics, School of Medicine
    Background and aims: Identifying simple markers of risk for worsening glucose can allow care providers to target therapeutic interventions according to risk of worsening glycemic control. We aimed to determine which routine clinical measures herald near-term glycemic worsening in early type 2 diabetes(T2D). Methods: The Early Diabetes Intervention Program (EDIP) was a clinical trial in individuals with screendetected T2D [HbA1C 6.3+0.63%(45+5mmol/mol)]. During the trial some participants experienced worsening fasting blood glucose (FBG). We investigated the time course of FBG, HbA1c, weight, and other clinical factors to determine which might herald glycemic worsening over the next year. Results: Progressors (62/219, 28.5%) had higher FBG than non-progressors at baseline [118 vs 130mg/dL (6.6 vs 7.2 mmol/L), p=<0.001]. FBG was stable except in the year of progression, when progressors exhibited a large 1-year rise [mean change 14.2mg/dL(0.79 mmol/L)]. Current FBG and antecedent year change in FBG were associated with progression(p<0.01), although the magnitude of change was too small to be of clinical utility (0.19 mg/dL; 0.01 mmol/L). Current or antecedent year change in HbA1c, weight, TG or HDL were not associated with progression. In the year of glycemic worsening, rising glucose was strongly associated with a concurrent increase in weight (p<0.001). Conclusions: Elevated FBG but not HbA1c identified individuals at risk for imminent glycemic worsening; the subsequent large rise in glucose was associated with a short-term increase in weight. Glucose and weight surveillance provide actionable information for those caring for patients with early diabetes.
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    Prevalence of Microvascular and Macrovascular Disease in the Glycemia Reduction Approaches in Diabetes - A Comparative Effectiveness (GRADE) Study Cohort
    (Elsevier, 2020-07) Mather, Kieren J.; Bebu, Ionut; Baker, Chelsea; Cohen, Robert M.; Crandall, Jill P.; DeSouza, Cyrus; Green, Jennifer B.; Kirkman, M. Sue; Krause-Steinrauf, Heidi; Larkin, Mary; Pettus, Jeremy; Seaquist, Elizabeth R.; Soliman, Elsayed Z.; Schroeder, Emily B.; Wexler, Deborah J.; Pop-Busui, Rodica; Medicine, School of Medicine
    Aims: The Glycemia Reduction Approaches in Diabetes - A Comparative Effectiveness (GRADE) trial is a randomized clinical trial comparing glycemic effects of four diabetes medications added to metformin in type 2 diabetes (T2D). Microvascular and macrovascular diseases are secondary outcomes. We evaluated the prevalence and risk factor relationships for microvascular and macrovascular complications in the GRADE cohort at study entry. Methods: Complication prevalence and risk factors were analyzed based on data from screening in all consenting participants meeting GRADE eligibility. Logistic regression and Z-statistics were used to assess risk factor relationships with complications. Results: We enrolled 5047 T2D participants [mean age 57 years; 36% female; mean known T2D duration 4 years (all < 10 years); mean HbA1c 8.0% (∼64 mmol/mol) at screening]. Urinary albumin/creatinine ratio (ACR) ≥ 30 mg/gram was present in 15.9% participants; peripheral neuropathy (by Michigan Neuropathy Screening Instrument) in 21.5%; cardiovascular autonomic neuropathy by electrocardiography-derived indices in 9.7%; self-reported retinopathy in 1.0%. Myocardial infarction ascertained by self-report or electrocardiogram was present in 7.3%, and self-reported history of stroke in 2.0%. Conclusions: In the GRADE cohort with < 10 years of T2D and a mean HbA1c of 8.0%, diabetes complications were present in a substantial fraction of participants, more so than might otherwise have been expected.
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    Retinopathy predicts progression of fasting plasma glucose: An Early Diabetes Intervention Program (EDIP) analysis
    (Elsevier, 2017-03) Patel, Yash R.; Kirkman, M. Sue; Considine, Robert V.; Hannon, Tamara S.; Mather, Kieren J.; Department of Medicine, School of Medicine
    Background Retinopathy is increasingly recognized in prediabetic populations, and may herald increased risk of metabolic worsening. The Early Diabetes Intervention Program (EDIP) evaluated worsening of glycemia in screen-detected Type 2 diabetes, following participants for up to 5 years. Here we have evaluated whether the presence of retinopathy at the time of detection of diabetes was associated with accelerated progression of glycemia. Methods We prospectively studied 194 participants from EDIP with available baseline retinal photographs. Retinopathy was determined at baseline using 7-field fundus photography and defined as an Early Treatment of Diabetic Retinopathy Study Scale grading score of ≥ 20. Results At baseline, 12% of participants had classical retinal lesions indicating retinopathy. In univariate Cox proportional hazard analysis, the presence of retinopathy at baseline was associated with a doubled risk of progression of fasting plasma glucose (HR 2.02; 95% CI 1.05–3.89). The retinopathy effect was robust to individual adjustment for age and glucose, the most potent determinants of progression in EDIP. Conclusion Retinopathy was associated with increased risk of progression of fasting plasma glucose among adults with screen-detected, early diabetes. Early detection of retinopathy may help individualize more aggressive therapy to prevent progressive metabolic worsening in early diabetes.