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Expert calls for better ways to preserve beta cell function in youth



New ways to preserve beta cell function in youth with impaired glucose tolerance or recently diagnosed type 2 diabetes mellitus are needed, because neither metformin alone nor metformin plus glargine are making a dent.

Dr. Sonia Caprio of Yale University, New Haven, Conn. Doug Brunk/MDedge News

Dr. Sonia Caprio

At the same time, the SEARCH for Diabetes in Youth trial showed that the incidence of T2DM in U.S. youth continues to rise, especially among Native Americans and non-Hispanic blacks (P less than .001 for both associations; N Engl J Med. 2017;376:1419-29). In addition, the earlier Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) study showed that rapid treatment failure in youth-onset T2DM was associated with loss of beta cell function (N Engl J Med. 2012;366:2247-56).

“Early treatment of youth with impaired glucose tolerance or type 2 diabetes may require other medications alone or in combination or for longer periods of time to combat the severe insulin resistance of puberty and arrest progressive loss of beta cell function,” Sonia Caprio, MD, said at the World Congress on Insulin Resistance, Diabetes & Cardiovascular Disease.

She based her remarks on a review of the recently completed multicenter Restoring Insulin Secretion (RISE) Pediatric Medication Study, (Diabetes Care 2018;41[8]:1717-25). It set out to answer the following question: In adolescents with impaired glucose tolerance or recently diagnosed T2DM, can beta cell function be preserved or improved during 12 months of active treatment and maintained for 3 months following the withdrawal of therapy?

To find out, Dr. Caprio, a pediatric endocrinologist at Yale University, New Haven, Conn., and her colleagues enrolled 91 youth who were randomized to one of two treatment arms: metformin alone titrated over 4 weeks from 500 mg/day to a 1,000 mg twice daily dose (modified if necessary due to GI symptoms), or to glargine followed by metformin. This group received once-daily insulin glargine, titrated twice weekly over 1 month based on daily self-monitoring of blood glucose to a goal of 80-90 mg/dL. Glargine was discontinued after 3 months and metformin was titrated. Beta-cell function (insulin sensitivity paired with beta-cell responses) was assessed by the two-step hyperglycemic clamp at baseline, 12 months (on treatment), and 15 months (3 months off treatment). All clinical data were collected 3 months after discontinuation of active treatment.

Dr. Caprio described the two-step hyperglycemic clamp as “a robust approach to quantification of insulin sensitivity and beta-cell responses to both glucose and the nonglucose secretagogue arginine. It provides mechanistic insights into how the tested interventions affected two key metabolic defects of type 2 diabetes: insulin sensitivity and beta cell responses.”

The mean age of patients was 14 years, 71% were female, their mean body mass index was 37 kg/m2. The researchers observed no significant differences between treatment groups at baseline, 12 months, or 15 months in beta cell function, BMI percentile, hemoglobin A1c, fasting glucose, or oral glucose tolerance test 2-hour glucose results. In both treatment groups, clamp-measured beta cell function was significantly lower at 12 and 15 months, compared with baseline. HbA1c fell transiently at 6 months within both groups. BMI was higher in the glargine followed by metformin versus metformin alone group between 3 and 9 months. Only 5% of participants discontinued the interventions, and both treatments were well tolerated.

“These findings are discouraging,” Dr. Caprio said. “They contrast with previous studies in adults showing an improvement in beta cell function with metformin or insulin for type 2 diabetes prevention and treatment.” Results of the RISE Pediatric Medication Study “call for further studies to better understand the physiology underlying beta cell dysfunction in youth to identify effective treatment options. Better approaches to prevent and treat obesity in youth are critically needed.”

Dr. Caprio reported having no disclosures.

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