Endocrine Abstracts

Background: It becomes increasingly evident that features of the metabolic syndrome are already present in young obese patients. Especially an impaired glucose metabolism with insulin resistance is an alarming sign of existing comorbidity of childhood obesity. Metformin has been argued as one pharmacological option to improve impaired glucose metabolism at least in obese adults. So far three prospective randomized studies were performed in childhood cohorts with <30 patients each (Kay 2001, Freemark 2001, Srinivasan 2006), suggesting a beneficial effect of metformin, however with low significances. To further gain evidence for the actual treatment with metformin we conducted a randomized, placebo controlled study in larger obesity childhood cohort.

Methods: We included obese non-diabetic children and adolescents (age range: 10–17 years.) with insulin resistance (HOMA>97. Perc.) and/or impaired glucose tolerance (total n=243). After an initial 6 month weight reduction program only those patients with unsuccessful weight reduction and persistent insulin resistance were recruited for the metformin treatment (n=67). The 67 patients were randomized and treated either with placebo or 2×500 mg metformin for 6 month. At baseline and after 6 month anthropometric (BMI-SDS, body composition, waist circumference) and metabolic parameters (oral glucose tolerance, HOMA, ISI, lipids) were measured.

Results: In 53% vs 36% (metformin vs placebo) the BMI and in 73% vs 54% (metformin versus placebo) HOMA was reduced after 6 month. But statistically comparing the placebo and treatment group did not revealed significant changes of all weight or glucose metabolic parameters (BMI-SDS, body composition, HOMA, ISI, lipids). Drop outs rate was 9% (n=6; n=1 metformin, n=5 placebo).

Conclusion: The lack of significant difference of all tested parameters of glucose metabolism in the metformin treatment vs placebo group of this so far largest metformin treatment cohort of obese children does not support the use of metformin in childhood obesity to improve insulin resistance, at least in addition to multiprofessional obesity programs.