et al. Routine Data Sources Challenge International Diabetes Federation Extrapolations of National Diabetes Prevalence in

We note with interest the approach ofBopp et al. (1) in providing conser-vative estimates for the prevalence of diabetes in Switzerland and welcome their critical comparison with the 2010 fig-ures from the International Diabetes Feder-ation (IDF) Diabetes Atlas. They show that IDF figures were over twice as high as their estimates. The authors rightly point out that prevalence data on diabetes from many countries are scarce. In providing national, regional, and global estimates, decisions need to be made on which study or studies are used for a particular country. If a high-quality, up-to-date, nationally representa-tive study in which glucose was measure