Effects of lifestyle intervention and metformin on weight management and markers of metabolic syndrome in obese adolescents

Abstract

Purpose: The purposes of this study are threefold: to determine what components of the metabolic syndrome are present in obese adolescents, to determine what differences exist in the effects of lifestyle intervention versus lifestyle intervention plus metformin on weight management and select markers of metabolic syndrome in obese adolescents, and to determine which factors predict weight loss in obese adolescents treated with lifestyle changes and metformin.

Data sources: The study was a secondary data analysis utilizing a retrospective chart review of 63 obese adolescents aged 11 through 18 who were treated for obesity at the LeBonheur Youth Lifestyle Clinic from January 1, 2000, through June 30, 2005. Lifestyle interventions included diet, exercise, and counseling. The medication utilized was metformin. Outcomes evaluated included body mass index, relative body mass index (RBMI), weight, waist and hip circumference, blood pressure, serum lipid levels, fasting plasma glucose, 2-h oral glucose tolerance tests, and insulin levels. Changes in mean values between groups were evaluated using the General Linear Models procedure. Logistic regression was utilized to determine which factors might predict weight loss.

Conclusions: The metformin group (N= 37) tended to be heavier, older, and had more components of the metabolic syndrome than the nonmetformin group (N= 26). All components of the metabolic syndrome were present in both groups (overall prevalence 55%). Both groups had a downward trend in RBMI, a surrogate marker for weight loss, but only the metformin group had a significant loss in RBMI points from baseline to end. There was a trend toward better diastolic blood pressure at 6 months in the metformin group (p= 0.06), which was not seen in the nonmetformin group. The only predictors of weight loss were higher RBMI (those who were heavier lost more) and the absence of type 2 diabetes mellitus (type 2 DM) (those with type 2 DM were less likely to lose 10 or more points in RBMI).

Implications for practice: All components of the metabolic syndrome are present in obese adolescents. The use of lifestyle changes and lifestyle changes plus metformin both produce some degree of weight loss, but subjects on metformin in this study lost significantly more RBMI points than those on lifestyle changes alone. Subjects with type 2 DM are less likely to lose weight than those without type 2 DM. Larger studies and studies with subjects more representative of the general population need to be carried out to assist in the development of evidence-based practice guidelines.