In the epidemiological study of Hsia et al. , the use of metformin in children and adolescents aged 0–18 years in the UK was investigated based on data from the UK database of IMS Disease Analyzer. Our longitudinal data (2000–2010) from similar databases in Germany (IMS Disease Analyzer Germany)  and France (IMS Disease Analyzer France) partly confirmed these results.
We found 195 children aged 1–18 years with 623 metformin prescriptions in 121 German practices and 269 children with 575 metformin prescriptions in 165 practices in France. In Germany, 74.3% of patients were female; of these, 62.6% were aged 16–18 years. In France, 54.6% of patients were female, out of whom 19.2% were aged 16–18 years.
The main indication for the prescription of metformin was diabetes mellitus, with the majority of patients having a diagnosis of type 2 diabetes. In Germany, metformin was prescribed in 80.8% of female and 85.3% of male patients for diabetes type 2. In France, these figures were 91.1 and 93.0%, respectively. The share of diabetes as a prescription indication is rather different in Germany and France from that which Hsia et al.  reported for the UK, where polycystic ovary syndrome was the most common indication for metformin prescriptions in girls. In the UK, however, 290 of 337 (86.1%) patients had at least one diagnosis of diabetes, even if it was not specified as the indication for the metformin prescription (Figure 1).
In several studies, metformin was shown to be safe and effective as a treatment for type 2 diabetes in paediatric patients . Metformin was approved by the US Food and Drug Administration (FDA) for use in adults with type 2 diabetes in 1994 .
Our primary care data confirm the results of the study of Hsia et al.  regarding the age and gender structure of children treated with metformin in Germany. The main difference between their study and our analysis concerns the documented indications for metformin in Germany and France. The reason for this may, however, be related more to the documentation behaviour of doctors.