Taffy Makaya, Rebecca Poole and Kavitha Rozario
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Other indications for prescribing Metformin included polycystic ovarian
syndrome (PCOS) and diabetes [61].
A meta-analysis and systematic review was reported by Bouza et al.
(2010) to assess the efficacy and safety of Metformin for childhood obesity
[62]; their results identified 7 trials which met the inclusion criteria. These
trials compared Metformin with placebo and employed behavioural co-
interventions, with an average follow-up of 6 months. Metformin was shown
to provide a significant decrease in BMI of -1.90(-3 to -8). The main side
effects reported were gastrointestinal, and no serious adverse effects were
reported.
The MOCA trial was a UK based double-blind, placebo-controlled study,
carried out across 6 paediatric endocrine centres. This trial investigated the
effects of Metformin versus placebo in obese children and young people with
hyperinsulinemia and/or impaired fasting glucose or impaired glucose
tolerance. The results showed that Metformin therapy was associated with a
significant reduction in BMI-SDS compared with placebo at 6 months [mean
difference -0.1 SD (95% confidence interval -0.18 to -0.02), P = 0.02].
Significant improvements at 3 months were found in the Metformin group:
fasting glucose, -0.16mmol/litre (-0.31 to -0.00), P = 0.047; alanine
aminotransferase, 19% (5-36%), P=0.008; and adiponectin to leptin ratio, 32%
(4-67%), P = 0.02. Study results suggest that Metformin is a safe and effective
treatment for childhood obesity [63].
A further systematic review of randomised controlled trials assessing the
use of Metformin in obese children without diabetes mellitus examined 14
studies, with a total of 946 children aged 10 to 16 [64]. Results showed that
children taking Metformin had a pooled difference in BMI change of -
1.16kg/m^2 , and a pooled weight loss of -3.26kg. Weight loss was greater in
children with an initial BMI >35, younger children aged 12 or under, and at 6
months, but there being no statistically significant difference in weight at 12
months. No adverse effects of Metformin were reported by the authors.
Another systematic review of Metformin in obese non-diabetic
adolescents and children also concluded that Metformin had modest effects on
BMI reduction [65]. Brufani et al. examined 11 trials, 9 of which concluded
Metformin was associated with a small but significant reduction in BMI (from
- 1.1 to -2.7kg/m^2 ). Again results indicated that there was no statistically
significant weight loss at 12 months [65]. These results suggest that there is
possibly limited long-term impact on weight loss with metformin. These
studies do not provide information on the long-term efficacy of metformin