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Dive into the research topics where David C. Klonoff is active.

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Featured researches published by David C. Klonoff.


Current Medical Research and Opinion | 2008

Exenatide effects on diabetes, obesity, cardiovascular risk factors and hepatic biomarkers in patients with type 2 diabetes treated for at least 3 years.

David C. Klonoff; John B. Buse; Loretta L. Nielsen; Xuesong Guan; Christopher L. Bowlus; John H. Holcombe; Matthew Wintle; David Maggs

BACKGROUND Exenatide, an incretin mimetic for adjunctive treatment of type 2 diabetes (T2DM), reduced hemoglobin A(1c) (A1C) and weight in clinical trials. The objective of this study was to evaluate the effects of > or = 3 years exenatide therapy on glycemic control, body weight, cardiometabolic markers, and safety. METHODS Patients from three placebo-controlled trials and their open-label extensions were enrolled into one open-ended, open-label clinical trial. Patients were randomized to twice daily (BID) placebo, 5 mug exenatide, or 10 mug exenatide for 30 weeks, followed by 5 mug exenatide BID for 4 weeks, then 10 mug exenatide BID for > or = 3 years of exenatide exposure. Patients continued metformin and/or sulfonylureas. RESULTS 217 patients (64% male, age 58 +/- 10 years, weight 99 +/- 18 kg, BMI 34 +/- 5 kg/m(2), A1C 8.2 +/- 1.0% [mean +/- SD]) completed 3 years of exenatide exposure. Reductions in A1C from baseline to week 12 (-1.1 +/- 0.1% [mean +/- SEM]) were sustained to 3 years (-1.0 +/- 0.1%; p < 0.0001), with 46% achieving A1C < or = 7%. Exenatide progressively reduced body weight from baseline (-5.3 +/- 0.4 kg at 3 years; p < 0.0001). Patients with elevated serum alanine aminotransferase (ALT) at baseline (n = 116) had reduced ALT (-10.4 +/- 1.5 IU/L; p < 0.0001) and 41% achieved normal ALT. Patients with elevated ALT at baseline tended to lose more weight than patients with normal ALT at baseline (-6.1 +/- 0.6 kg vs. -4.4 +/- 0.5 kg; p = 0.03), however weight change was minimally correlated with baseline ALT (r = -0.01) or ALT change (r = 0.31). Homeostasis Model Assessment B (HOMA-B), blood pressure, and aspartate aminotransferase (AST) all improved. A subset achieved 3.5 years of exenatide exposure and had serum lipids available for analysis (n = 151). Triglycerides decreased 12% (p = 0.0003), total cholesterol decreased 5% (p = 0.0007), LDL-C decreased 6% (p < 0.0001), and HDL-C increased 24% (p < 0.0001). Exenatide was generally well tolerated. The most frequent adverse event was mild-to-moderate nausea. The main limitation of this study is the open-label, uncontrolled nature of the study design which does not provide a placebo group for comparison. CONCLUSION Adjunctive exenatide treatment for > or = 3 years in T2DM patients resulted in sustained improvements in glycemic control, cardiovascular risk factors, and hepatic biomarkers, coupled with progressive weight reduction.


The New England Journal of Medicine | 2013

Threshold-Based Insulin-Pump Interruption for Reduction of Hypoglycemia

Richard M. Bergenstal; David C. Klonoff; Satish K. Garg; Bruce W. Bode; Melissa Meredith; Robert Slover; Andrew J. Ahmann; John B. Welsh; Scott Lee; Francine R. Kaufman

BACKGROUND The threshold-suspend feature of sensor-augmented insulin pumps is designed to minimize the risk of hypoglycemia by interrupting insulin delivery at a preset sensor glucose value. We evaluated sensor-augmented insulin-pump therapy with and without the threshold-suspend feature in patients with nocturnal hypoglycemia. METHODS We randomly assigned patients with type 1 diabetes and documented nocturnal hypoglycemia to receive sensor-augmented insulin-pump therapy with or without the threshold-suspend feature for 3 months. The primary safety outcome was the change in the glycated hemoglobin level. The primary efficacy outcome was the area under the curve (AUC) for nocturnal hypoglycemic events. Two-hour threshold-suspend events were analyzed with respect to subsequent sensor glucose values. RESULTS A total of 247 patients were randomly assigned to receive sensor-augmented insulin-pump therapy with the threshold-suspend feature (threshold-suspend group, 121 patients) or standard sensor-augmented insulin-pump therapy (control group, 126 patients). The changes in glycated hemoglobin values were similar in the two groups. The mean AUC for nocturnal hypoglycemic events was 37.5% lower in the threshold-suspend group than in the control group (980 ± 1200 mg per deciliter [54.4 ± 66.6 mmol per liter] × minutes vs. 1568 ± 1995 mg per deciliter [87.0 ± 110.7 mmol per liter] × minutes, P<0.001). Nocturnal hypoglycemic events occurred 31.8% less frequently in the threshold-suspend group than in the control group (1.5 ± 1.0 vs. 2.2 ± 1.3 per patient-week, P<0.001). The percentages of nocturnal sensor glucose values of less than 50 mg per deciliter (2.8 mmol per liter), 50 to less than 60 mg per deciliter (3.3 mmol per liter), and 60 to less than 70 mg per deciliter (3.9 mmol per liter) were significantly reduced in the threshold-suspend group (P<0.001 for each range). After 1438 instances at night in which the pump was stopped for 2 hours, the mean sensor glucose value was 92.6 ± 40.7 mg per deciliter (5.1 ± 2.3 mmol per liter). Four patients (all in the control group) had a severe hypoglycemic event; no patients had diabetic ketoacidosis. CONCLUSIONS This study showed that over a 3-month period the use of sensor-augmented insulin-pump therapy with the threshold-suspend feature reduced nocturnal hypoglycemia, without increasing glycated hemoglobin values. (Funded by Medtronic MiniMed; ASPIRE ClinicalTrials.gov number, NCT01497938.).


Diabetes Care | 1997

Noninvasive Blood Glucose Monitoring

David C. Klonoff

The concentration of glucose in the blood may soon be measured noninvasively, without puncturing the finger to obtain a drop of blood. Current prototype devices for this purpose require greater accuracy and miniaturization to be commercially viable. No such device has been approved for marketing by the U.S. Food and Drug Administration. The technology used for noninvasive blood glucose monitoring involves either radiation or fluid extraction. With radiation technology, an energy beam is 1) applied to the body, 2) modified proportionate to the concentration of glucose in the blood, and 3) measured. The blood glucose concentration is then calculated. With fluid extraction technology, a body fluid containing glucose in a concentration proportionate to the blood glucose concentration is extracted and measured. The blood glucose concentration is then calculated. The most promising technologies are 1) near-infrared light spectroscopy, 2) far-infrared radiation spectroscopy, 3) radio wave impedance, 4) optical rotation of polarized light, 5) fluid extraction from skin, and 6) interstitial fluid harvesting. Each method has features predictive of commercial viability, as well as technical problems to overcome.


The Journal of Clinical Endocrinology and Metabolism | 2011

Continuous glucose monitoring: an Endocrine Society Clinical Practice Guideline.

David C. Klonoff; Bruce Buckingham; Jens Sandahl Christiansen; Victor M. Montori; William V. Tamborlane; Robert A. Vigersky; Howard Wolpert

OBJECTIVE The aim was to formulate practice guidelines for determining settings where patients are most likely to benefit from the use of continuous glucose monitoring (CGM). PARTICIPANTS The Endocrine Society appointed a Task Force of experts, a methodologist, and a medical writer. EVIDENCE This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence. CONSENSUS PROCESS One group meeting, several conference calls, and e-mail communications enabled consensus. Committees and members of The Endocrine Society, the Diabetes Technology Society, and the European Society of Endocrinology reviewed and commented on preliminary drafts of these guidelines. CONCLUSIONS The Task Force evaluated three potential uses of CGM: 1) real-time CGM in adult hospital settings; 2) real-time CGM in children and adolescent outpatients; and 3) real-time CGM in adult outpatients. The Task Force used the best available data to develop evidence-based recommendations about where CGM can be beneficial in maintaining target levels of glycemia and limiting the risk of hypoglycemia. Both strength of recommendations and quality of evidence were accounted for in the guidelines.


Diabetes Technology & Therapeutics | 2013

Recommendations for Standardizing Glucose Reporting and Analysis to Optimize Clinical Decision Making in Diabetes: The Ambulatory Glucose Profile (AGP)

Richard M. Bergenstal; Andrew J. Ahmann; Timothy L. Bailey; Roy W. Beck; Joan Bissen; Bruce Buckingham; Larry C. Deeb; Robert H. Dolin; Satish K. Garg; Robin Goland; Irl B. Hirsch; David C. Klonoff; Davida F. Kruger; Glenn Matfin; Roger S. Mazze; Beth A. Olson; Christopher G. Parkin; Anne L. Peters; Margaret A. Powers; Henry Rodriguez; Phil Southerland; Ellie S. Strock; William V. Tamborlane; David M. Wesley

Abstract Underutilization of glucose data and lack of easy and standardized glucose data collection, analysis, visualization, and guided clinical decision making are key contributors to poor glycemic control among individuals with type 1 diabetes. An expert panel of diabetes specialists, facilitated by the International Diabetes Center and sponsored by the Helmsley Charitable Trust, met in 2012 to discuss recommendations for standardization of analysis and presentation of glucose monitoring data, with the initial focus on data derived from CGM systems. The panel members were introduced to a universal software report, the Ambulatory Glucose Profile (AGP), and asked to provide feedback on its content and functionality, both as a research tool and in clinical settings. This paper provides a summary of the topics and issues discussed during the meeting and presents recommendations from the expert panel regarding the need to standardize glucose profile summary metrics and the value of a uniform glucose report to aid clinicians, researchers, and patients.


Diabetes Technology & Therapeutics | 2012

Reduction in Duration of Hypoglycemia by Automatic Suspension of Insulin Delivery: The In-Clinic ASPIRE Study

Satish K. Garg; Ronald L. Brazg; Timothy S. Bailey; Bruce Buckingham; Robert H. Slover; David C. Klonoff; John H. Shin; John B. Welsh; Francine R. Kaufman

BACKGROUND The efficacy of automatic suspension of insulin delivery in induced hypoglycemia among subjects with type 1 diabetes was evaluated. SUBJECTS AND METHODS In this randomized crossover study, subjects used a sensor-augmented insulin pump system with a low glucose suspend (LGS) feature that automatically stops insulin delivery for 2 h following a sensor glucose (SG) value ≤70 mg/dL. Subjects fasted overnight and exercised until their plasma glucose (measured with the YSI 2300 STAT Plus™ glucose and lactate analyzer [YSI Life Sciences, Yellow Springs, OH]) value reached ≤85 mg/dL on different occasions separated by washout periods lasting 3-10 days. Exercise sessions were done with the LGS feature turned on (LGS-On) or with continued insulin delivery regardless of SG value (LGS-Off). The order of LGS-On and LGS-Off sessions was randomly assigned. YSI glucose data were used to compare the duration and severity of hypoglycemia from successful LGS-On and LGS-Off sessions and to estimate the risk of rebound hyperglycemia after pump suspension. RESULTS Fifty subjects attempted 134 sessions, 98 of which were successful. The mean±SD hypoglycemia duration was less during LGS-On than during LGS-Off sessions (138.5±76.68 vs. 170.7±75.91 min, P=0.006). During LGS-On compared with LGS-Off sessions, mean nadir YSI glucose was higher (59.5±5.72 vs. 57.6±5.69 mg/dL, P=0.015), as was mean end-observation YSI glucose (91.4±41.84 vs. 66.2±13.48 mg/dL, P<0.001). Most (53.2%) end-observation YSI glucose values in LGS-On sessions were in the 70-180 mg/dL range, and none was >250 mg/dL. CONCLUSIONS Automatic suspension of insulin delivery significantly reduced the duration and severity of induced hypoglycemia without causing rebound hyperglycemia.


Journal of diabetes science and technology | 2008

Consensus Report of the Coalition for Clinical Research—Self-Monitoring of Blood Glucose

David C. Klonoff; Richard M. Bergenstal; Lawrence Blonde; Sophia Austin Boren; Timothy S. Church; Jenifer Gaffaney; Lois Jovanovic; David M. Kendall; Craig Kollman; Boris P. Kovatchev; Claudia Leippert; David Raymond Owens; William H. Polonsky; G. Reach; Eric Renard; Michael C. Riddell; Richard R. Rubin; Oliver Schnell; Linfa M. Siminiero; Robert A. Vigersky; Darrell M. Wilson; Alison Okada Wollitzer

The Coalition for Clinical Research—Self-Monitoring of Blood Glucose Scientific Board, a group of nine academic clinicians and scientists from the United States and Europe, convened in San Francisco, California, on June 11–12, 2008, to discuss the appropriate uses of self-monitoring of blood glucose (SMBG) and the measures necessary to accurately assess the potential benefit of this practice in noninsulin-treated type 2 diabetes mellitus (T2DM). Thirteen consultants from the United States, Europe, and Canada from academia, practice, and government also participated and contributed based on their fields of expertise. These experts represent a range of disciplines that include adult endocrinology, pediatric endocrinology, health education, mathematics, statistics, psychology, nutrition, exercise physiology, and nursing. This coalition was organized by Diabetes Technology Management, Inc. Among the participants, there was consensus that: protocols assessing the performance of SMBG in noninsulin treated T2DM must provide the SMBG intervention subjects with blood glucose (BG) goals and instructions on how to respond to BG data in randomized controlled trials (RCTs); intervention subjects in clinical trials of SMBG-driven interventions must aggressively titrate their therapeutic responses or lifestyle changes in response to hyperglycemia; control subjects in clinical trials of SMBG must be isolated from SMBG-driven interventions and not be contaminated by physician experience with study subjects receiving a SMBG intervention; the best endpoints to measure in a clinical trial of SMBG in T2DM include delta Hemoglobin A1c levels, hyperglycemic events, hypoglycemic events, time to titrate noninsulin therapy to a maximum necessary dosage, and quality of life indices; either individual randomization or cluster randomization may be appropriate methods for separating control subjects from SMBG intervention subjects, provided that precautions are taken to avoid bias and that the sample size is adequate; treatment algorithms for assessing SMBG in T2DM may include a dietary, exercise, and/or medication intervention, which are all titratable according to the SMBG values; the medical literature contains very little information about the performance of SMBG in T2DM from RCTs in which treatment algorithms were used for dysglycemic values; and research on the performance of SMBG in T2DM based on sound scientific principles and clinical practices is needed at this time.


Journal of diabetes science and technology | 2007

The Artificial Pancreas: How Sweet Engineering Will Solve Bitter Problems

David C. Klonoff

An artificial pancreas is a closed-loop system containing only synthetic materials which substitutes for an endocrine pancreas. No artificial pancreas system is currently approved; however, devices that could become components of such a system are now becoming commercially available. An artificial pancreas will consist of functionally integrated components that will continuously sense glucose levels, determine appropriate insulin dosages, and deliver the insulin. Any proposed closed loop system will be closely scrutinized for its safety, efficacy, and economic impact. Closed loop control utilizes models of glucose homeostasis which account for the influences of feeding, stress, insulin, exercise, and other factors on blood glucose levels. Models are necessary for understanding the relationship between blood glucose levels and insulin dosing; developing algorithms to control insulin dosing; and customizing each users system based on individual responses to factors that influence glycemia. Components of an artificial pancreas are now being developed, including continuous glucose sensors; insulin pumps for parenteral delivery; and control software, all linked through wireless communication systems. Although a closed-loop system providing glucagon has not been reported in 40 years, the use of glucagon to prevent hypoglycemia is physiologically attractive and future devices might utilize this hormone. No demonstration of long-term closed loop control of glucose in a free-living human with diabetes has been reported to date, but many centers around the world are working on closed loop control systems. It is expected that many types of artificial pancreas systems will eventually be available, and they will greatly benefit patients with diabetes.


Journal of diabetes science and technology | 2011

Consensus Report: The Current Role of Self-Monitoring of Blood Glucose in Non-Insulin-Treated Type 2 Diabetes

David C. Klonoff; Lawrence Blonde; George Cembrowski; Antonio Roberto Chacra; Guillaume Charpentier; Stephen Colagiuri; George Dailey; Robert A. Gabbay; Lutz Heinemann; David Kerr; Antonio Nicolucci; William H. Polonsky; Oliver Schnell; Robert A. Vigersky; Jean-François Yale

The Coalition for Clinical Research—Self-Monitoring of Blood Glucose Scientific Board convened a meeting in San Francisco, CA, July 20–21, 2011, to discuss the current practice of self-monitoring of blood glucose (SMBG) in non-insulin-treated (NIT) type 2 diabetes mellitus (T2DM). Twelve physician panel members from academia, practice, and government attended this meeting. These experts came from the United States, Brazil, Canada, France, Germany, Italy, and the United Kingdom. In addition, three consultants from Australia, Germany, and the United States contributed to the groups final report. This coalition was organized by Diabetes Technology Society. Self-monitoring of blood glucose was studied from eight perspectives related to patients with NIT T2DM: (1) epidemiological studies; (2) randomized controlled trials (RCT)s and meta-analyses; (3) targets, timing, and frequency of SMBG use; (4) incidence and role of SMBG in preventing hypoglycemia with single-drug regimens and combination regimens consisting of antihyperglycemic agents other than secretagogues and insulin; (5) comparison of SMBG with continuous glucose monitoring; (6) technological capabilities and limitations of SMBG; (7) barriers to appropriate use of SMBG; and (8) methods and end points for appropriate future clinical trials. The panel emphasized recent studies, which reflect the current approach for applying this intervention. Among the participants there was consensus that: SMBG is an established practice for patients with NIT T2DM, and to be most effective, it should be performed in a structured format where information obtained from this measurement is used to guide treatment; New, high-quality efficacy data from RCTs have demonstrated efficacy of SMBG in NIT T2DM in trials reported since 2008; Both patients and health care professionals require education on how to respond to the data for SMBG to be effective; and Additional well-defined studies are needed to assess the benefits and costs of SMBG with end points not limited to hemoglobin A1c.


Diabetes Care | 2008

Efficacy and Safety of Technosphere Inhaled Insulin Compared With Technosphere Powder Placebo in Insulin-Naive Type 2 Diabetes Suboptimally Controlled With Oral Agents

Julio Rosenstock; Richard M. Bergenstal; Ralph A. DeFronzo; Irl B. Hirsch; David C. Klonoff; Anders Hasager Boss; David Kramer; Richard Petrucci; Wen Yu; Brian L. Levy

OBJECTIVE—This double-blind, placebo-controlled, randomized, multicenter, parallel-group study compared the efficacy, safety, and tolerability of Technosphere insulin with Technosphere powder as placebo in insulin-naive type 2 diabetic patients whose diabetes was suboptimally controlled with oral antidiabetic agents. RESEARCH DESIGN AND METHODS—Patients (n = 126) were randomly assigned to 12 weeks of therapy with Technosphere insulin or Technosphere powder after lifestyle education on nutrition, exercise, and instructions on inhaler use. The primary efficacy outcome was change in A1C from baseline to study end, and the secondary efficacy outcome was area under the curve for postprandial glucose levels during a meal test at treatment weeks 4, 8, and 12. RESULTS—A1C reduction from a mean baseline of 7.9% was greater with Technosphere insulin than with Technosphere powder (−0.72 vs. −0.30%; P = 0.003). Postprandial glucose excursions were reduced by 56% with Technosphere insulin compared with baseline, and maximal postprandial glucose levels were reduced by 43% compared with Technosphere powder. Incidences of hypoglycemia, hyperglycemia, cough, and other adverse events were low in both groups. Body weight was unchanged in both groups. CONCLUSIONS—Technosphere insulin was well tolerated and demonstrated significant improvement in glycemic control with clinically meaningful reductions in A1C levels and postprandial glucose concentrations after 12 weeks of treatment.

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David Kerr

Royal Bournemouth Hospital

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Satish K. Garg

University of Colorado Denver

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Robert A. Vigersky

Walter Reed National Military Medical Center

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Lutz Heinemann

University of Düsseldorf

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