Steven M Willi

Publications (9)92.32 Total impact

• Article: Sensor-augmented pump therapy for A1C reduction (STAR 3) study: results from the 6-month continuation phase.

  Richard M Bergenstal, William V Tamborlane, Andrew Ahmann, John B Buse, George Dailey, Stephen N Davis, Carol Joyce, Bruce A Perkins, John B Welsh, Steven M Willi, Michael A Wood
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  ABSTRACT: OBJECTIVE To examine the effects of crossing over from optimized multiple daily injection (MDI) therapy to sensor-augmented pump (SAP) therapy for 6 months, and the effects of 18 months' sustained use of SAP. RESEARCH DESIGN AND METHODS The 6-month, single-crossover continuation phase of Sensor-Augmented Pump Therapy for A1C Reduction (STAR 3) provided SAP therapy to 420 subjects who completed the 1-year randomized study. The primary outcome was change in A1C in the crossover group. RESULTS A1C values were initially lower in the continuing-SAP group than in the crossover group (7.4 vs. 8.0%, P < 0.001). A1C values remained reduced in the SAP group. After 3 months on the SAP system, A1C decreased to 7.6% in the crossover group (P < 0.001); this was a significant and sustained decrease among both adults and children (P < 0.05). CONCLUSIONS Switching from optimized MDI to SAP therapy allowed for rapid and safe A1C reductions. Glycemic benefits of SAP therapy persist for at least 18 months.
  Diabetes care 09/2011; 34(11):2403-5. · 8.09 Impact Factor
• Article: Effectiveness of sensor-augmented pump therapy in children and adolescents with type 1 diabetes in the STAR 3 study.

  Robert H Slover, John B Welsh, Amy Criego, Stuart A Weinzimer, Steven M Willi, Michael A Wood, William V Tamborlane
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  ABSTRACT: Maintenance of appropriate A1C values and minimization of hyperglycemic excursions are difficult for many pediatric patients with type 1 diabetes. Continuous glucose monitoring (CGM) sensor-augmented pump (SAP) therapy is an alternative to multiple daily injection (MDI) therapy in this population. Sensor-augmented pump therapy for A1C reduction (STAR 3) was a 1-yr trial that included 82 children (aged 7-12) and 74 adolescents (aged 13-18) with A1C values ranging from 7.4 to 9.5% who were randomized to either SAP or MDI therapy. Quarterly A1C values were obtained from all subjects. CGM studies were carried out at baseline, 6 months, and 12 months to quantify glycemic excursions [calculated as area under the glucose concentration-time curve (AUC)] and variability. In the SAP group, sensor compliance was recorded. Baseline A1C values were similar in subjects randomized to the SAP (8.26 ± 0.55%) and MDI groups (8.30 ± 0.53%). All subsequent A1C values showed significant (p < 0.05) treatment group differences favoring SAP therapy. Compared with the MDI group, subjects in the SAP group were more likely to meet age-specific A1C targets and had lower AUC values for hyperglycemia with no increased risk of hypoglycemia. Glucose variability improved in the SAP group compared to the MDI group. Children wore CGM sensors more often and were more likely to reach age-specific A1C targets than adolescents. SAP therapy allows both children and adolescents with marginally or inadequately controlled type 1 diabetes to reduce A1C values, hyperglycemic excursions, and glycemic variability in a rapid, sustainable, and safe manner.
  Pediatric Diabetes 07/2011; 13(1):6-11. · 2.16 Impact Factor
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  Article: Effectiveness of sensor-augmented insulin-pump therapy in type 1 diabetes.

  Richard M Bergenstal, William V Tamborlane, Andrew Ahmann, John B Buse, George Dailey, Stephen N Davis, Carol Joyce, Tim Peoples, Bruce A Perkins, John B Welsh, Steven M Willi, Michael A Wood
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  ABSTRACT: Recently developed technologies for the treatment of type 1 diabetes mellitus include a variety of pumps and pumps with glucose sensors. In this 1-year, multicenter, randomized, controlled trial, we compared the efficacy of sensor-augmented pump therapy (pump therapy) with that of a regimen of multiple daily insulin injections (injection therapy) in 485 patients (329 adults and 156 children) with inadequately controlled type 1 diabetes. Patients received recombinant insulin analogues and were supervised by expert clinical teams. The primary end point was the change from the baseline glycated hemoglobin level. At 1 year, the baseline mean glycated hemoglobin level (8.3% in the two study groups) had decreased to 7.5% in the pump-therapy group, as compared with 8.1% in the injection-therapy group (P<0.001). The proportion of patients who reached the glycated hemoglobin target (<7%) was greater in the pump-therapy group than in the injection-therapy group. The rate of severe hypoglycemia in the pump-therapy group (13.31 cases per 100 person-years) did not differ significantly from that in the injection-therapy group (13.48 per 100 person-years, P=0.58). There was no significant weight gain in either group. In both adults and children with inadequately controlled type 1 diabetes, sensor-augmented pump therapy resulted in significant improvement in glycated hemoglobin levels, as compared with injection therapy. A significantly greater proportion of both adults and children in the pump-therapy group than in the injection-therapy group reached the target glycated hemoglobin level. (Funded by Medtronic and others; ClinicalTrials.gov number, NCT00417989.)
  New England Journal of Medicine 07/2010; 363(4):311-20. · 53.30 Impact Factor
• Article: The effect of insulin on expression of genes and biochemical pathways in human skeletal muscle.

  Xuxia Wu, Jelai Wang, Xiangqin Cui, Lidia Maianu, Brian Rhees, James Rosinski, W Venus So, Steven M Willi, Michael V Osier, Helliner S Hill, Grier P Page, David B Allison, Mitchell Martin, W Timothy Garvey
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  ABSTRACT: To study the insulin effects on gene expression in skeletal muscle, muscle biopsies were obtained from 20 insulin sensitive individuals before and after euglycemic hyperinsulinemic clamps. Using microarray analysis, we identified 779 insulin-responsive genes. Particularly noteworthy were effects on 70 transcription factors, and an extensive influence on genes involved in both protein synthesis and degradation. The genetic program in skeletal muscle also included effects on signal transduction, vesicular traffic and cytoskeletal function, and fuel metabolic pathways. Unexpected observations were the pervasive effects of insulin on genes involved in interacting pathways for polyamine and S-adenoslymethionine metabolism and genes involved in muscle development. We further confirmed that four insulin-responsive genes, RRAD, IGFBP5, INSIG1, and NGFI-B (NR4A1), were significantly up-regulated by insulin in cultured L6 skeletal muscle cells. Interestingly, insulin caused an accumulation of NGFI-B (NR4A1) protein in the nucleus where it functions as a transcription factor, without translocation to the cytoplasm to promote apoptosis. The role of NGFI-B (NR4A1) as a new potential mediator of insulin action highlights the need for greater understanding of nuclear transcription factors in insulin action.
  Endocrine 03/2007; 31(1):5-17. · 1.42 Impact Factor
• Article: How low can we go...safely?: factors affecting intensive diabetes management.

  Steven M Willi
  Journal of Pediatrics 09/2006; 149(2):154-6. · 4.11 Impact Factor
• Article: Treatment of type 2 diabetes in childhood using a very-low-calorie diet.

  Steven M Willi, Kelley Martin, Farrah M Datko, Bethany P Brant
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  ABSTRACT: Pharmacologic agents currently approved for use in children with type 2 diabetes (metformin and insulin) are less than optimal for some patients. We evaluated the use of a ketogenic, very-low-calorie diet (VLCD) in the treatment of type 2 diabetes. We conducted a chart review of 20 children (mean age 14.5 +/- 0.4 years) who consumed a ketogenic VLCD in the treatment of type 2 diabetes. Several response variables (BMI, blood pressure, HbA(1c), blood glucose, and treatment regimens) were examined before, during, and up to 2 years after the diet and compared with a matched diabetic control group. Before starting the diet, 11 of 20 patients were treated with insulin and 6 with metformin. Mean daily blood glucose values fell from 8.9 +/- 1.1 to 5.5 +/- 0.38 mmol/l (P < 0.0001) in the first 3 days of the VLCD, allowing insulin and oral agents to be discontinued in all but one subject. BMI fell from 43.5 +/- 1.8 to 39.3 +/- 1.8 kg/m(2) (P < 0.0001) and HbA(1c) dropped from 8.8 +/- 0.6 to 7.4 +/- 0.6% (P < 0.005) as the diet was continued for a mean of 60 +/- 8 days (range 4-130 days), and none required resumption of antidiabetic medications. Sustained decreases in BMI and insulin requirements were observed in patients remaining on the VLCD for at least 6 weeks when compared with those of the control group. The ketogenic VLCD is an effective short-term, and possibly long-term, therapy for pediatric patients with type 2 diabetes. Blood glucose control and BMI improve, allowing the discontinuation of exogenous insulin and other antidiabetic agents. This diet, although strict, has potential as an alternative to pharmacologic therapies for this emerging subset of diabetic individuals.
  Diabetes Care 03/2004; 27(2):348-53. · 8.09 Impact Factor
• Article: Benefits of continuous subcutaneous insulin infusion in children with type 1 diabetes.

  Steven M Willi, Jonathan Planton, Leonard Egede, Sharon Schwarz
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  ABSTRACT: To examine the effect of continuous subcutaneous insulin infusion (CSII) therapy on parameters affecting long-term outcome in type 1 diabetes. Study design Height, weight, body mass index, insulin dose, glycosylated hemoglobin (HbA(1C)), and blood glucose data from home meter downloads were collected prospectively for analysis in 51 children (age, 10.7+/-3.1 years, mean+/-SD) throughout the 12 months before and after introducing CSII. Before pump initiation, HbA(1C) was relatively stable, but it fell to 7.7+/-0.2% (P<.001) within 3 months of CSII and remained decreased (7.9+/-0.1%) at 12 months (P<.01). In contrast, weight standard deviation score increased before CSII (from 0.50+/-0.13 to 0.60+/-0.13, P<.05), but remained unchanged (0.61+/-0.11) in the year thereafter. Although severe hypoglycemia (<50 mg/dL) was reduced in the entire cohort, HbA(1C) improved primarily in young children and teenagers. Comparison of glycemic responders (HbA(1C) <7.5, or a decrease >1% on CSII, n=23) with nonresponders demonstrated no differences with respect to gender, socioeconomic status, weight standard deviation score, body mass index, initial HbA(1C), frequency of hypoglycemia, or number of education visits before CSII. Continuous subcutaneous insulin infusion is effective in lowering HbA(1C) and the occurrence of severe nocturnal hypoglycemia without excessive weight gain in most children with type 1 diabetes. HbA(1C) response to CSII is poorer in preadolescents than in young children or teenagers.
  Journal of Pediatrics 01/2004; 143(6):796-801. · 4.11 Impact Factor
• Article: Effective use of thiazolidinediones for the treatment of glucocorticoid-induced diabetes.

  Steven M Willi, Adele Kennedy, Bethany P Brant, Penny Wallace, Nikki L Rogers, W Timothy Garvey
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  ABSTRACT: We evaluated the efficacy of a thiazolidinedione in the treatment of diabetes induced by glucocorticoids. We examined the effectiveness of troglitazone in seven patients with long-standing steroid-induced diabetes. Five of the seven subjects were treated with insulin alone, one was treated with both insulin and oral therapy and one was treated with oral therapy alone. The mean insulin dose in six of the seven subjects was 0.66+/-0.09 units/kg per day. Diabetes status was assessed by measuring serum fructosamine, HgbA1c, oral glucose and meal tolerance tests (OGTT and MTT) at baseline and after treatment for 5-8 weeks with troglitazone 400 mg/day. Troglitazone caused a significant decrease in fructosamine (274+/-32 vs. 217+/-22 mmol/l; P<0.01) and HgbA1C (7.8+/-0.4 vs. 7.2+/-0.4%; P<0.01) as well as decrements in the areas under the OGTT 2,308+/-156 vs. 1,937+/-127 mmol/l; P<0.05) and MTT glucose curves (4694+/-449 vs. 4057+/-437 mmol/l; P<0.05). In addition, the area under the insulin curve for the oral glucose tolerance test showed a significant increase from 27,438+/-4,488 to 41,946+/-6,048 pmol/l (P<0.05). Total and LDL cholesterol were also significantly decreased (6.4+/-0.9 vs. 5.0+/-0.6 mmol/l and 3.8+/-0.7 vs. 2.7+/-0.4 mmol/l, respectively, P<0.05). Fasting leptin values decreased by 23% despite an increase in body weight. Troglitazone is effective in the treatment of glucocorticoid-induced diabetes as manifested by lower measures of glycemia, HgbA1c, and post-prandial glucose values, while the doses of other diabetes medications remained unchanged or were reduced. The insulin-sensitizing drug also produced a marked increase in endogenous insulin secretion in response to glucose, lower total and LDL cholesterol, and decreased fasting leptin despite weight gain. Thiazolidinediones may improve diabetes-related parameters by antagonizing pathways of glucocorticoid-induced insulin resistance and by reversing adverse effects of glucocorticoids on beta cell function.
  Diabetes Research and Clinical Practice 12/2002; 58(2):87-96. · 2.75 Impact Factor
• Article: Troglitazone antagonizes metabolic effects of glucocorticoids in humans: effects on glucose tolerance, insulin sensitivity, suppression of free fatty acids, and leptin.

  Steven M Willi, Adele Kennedy, Penny Wallace, Elizabeth Ganaway, Nikki L Rogers, W Timothy Garvey
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  ABSTRACT: Glucocorticoids induce insulin resistance in humans, whereas thiazolidinediones enhance insulin sensitivity. Although the effects of glucocorticoids and thiazolidinediones have been assessed in isolation, interaction between these drugs, which both act as ligands for nuclear receptors, has been less well studied. Therefore, we examined the metabolic effects of dexamethasone and troglitazone, alone and in combination, for the first time in humans. A total of 10 healthy individuals with normal glucose tolerance (age 40 +/- 11 years, BMI 31 +/- 6.1 kg/m(2)) were sequentially studied at baseline, after 4 days of dexamethasone (4 mg/day), after 4-6 weeks on troglitazone alone (400 mg/day), and again after 4 days of dexamethasone added to troglitazone. Key metabolic variables included glucose tolerance assessed by blood glucose and insulin responses to an oral glucose tolerance test (OGTT), insulin sensitivity evaluated via hyperinsulinemic-euglycemic clamp, free fatty acids (FFAs) and FFA suppressibility by insulin during the clamp study, and fasting serum leptin. Dexamethasone drastically impaired glucose tolerance, with fasting and 2-h OGTT insulin values increasing by 2.3-fold (P < 0.001) and 4.4-fold (P < 0.001) over baseline values, respectively. The glucocorticoid also induced a profound state of insulin resistance, with a 34% reduction in maximal glucose disposal rates (GDRs; P < 0.001). Troglitazone alone increased GDRs by 20% over baseline (P = 0.007) and completely prevented the deleterious effects of dexamethasone on glucose tolerance and insulin sensitivity, as illustrated by a return of OGTT glucose and insulin values and maximal GDR to near-baseline levels. Insulin-mediated FFA suppressibility (FFA decline at 30 min during clamp/FFA at time 0) was also markedly reduced by dexamethasone (P = 0.002). Troglitazone had no effect per se, but it was able to normalize FFA suppressibility in subjects coadministered dexamethasone. Futhermore, the magnitudes of response of FFA suppressibility and GDR to dexamethasone were proportionate. The same was true for the reversal of dexamethasone-induced insulin resistance by troglitazone, but not in response to troglitazone alone. Leptin levels were increased 2.2-fold above baseline by dexamethasone. Again, troglitazone had no effect per se but blocked the dexamethasone-induced increase in leptin. Subjects experienced a 1.7-kg weight gain while taking troglitazone but no other untoward effects. We conclude that in healthy humans, thiazolidinediones antagonize the action of dexamethasone with respect to multiple metabolic effects. Specifically, troglitazone reverses both glucocorticoid-induced insulin resistance and impairment of glucose tolerance, prevents dexamethasone from impairing the antilipolytic action of insulin, and blocks the increase in leptin levels induced by dexamethasone. Even though changes in FFA suppressibility were correlated with dexamethasone-induced insulin resistance and its reversal by troglitazone, a cause-and-effect relationship cannot be established. However, the data suggest that glucocorticoids and thiazolidinediones exert fundamentally antagonistic effects on human metabolism in both adipose and muscle tissues. By preventing or reversing insulin resistance, troglitazone may prove to be a valuable therapeutic agent in the difficult clinical task of controlling diabetes in patients receiving glucocorticoids.
  Diabetes 11/2002; 51(10):2895-902. · 8.29 Impact Factor