The International Diabetes Federation (IDF) Atlas [1] has traditionally reported age-adjusted rates to estimate prevalence of hyperglycaemia in pregnancy (HIP). As a result, many studies that do not report prevalence rates aggregated into three or more age-groups may be excluded from the estimation of HIP prevalence. We aimed to determine whether removing age adjustment of prevalence would increase the yield of studies for inclusion into the IDF Atlas.
We looked at all studies that were identified for the IDF Atlas, including those excluded due to not having three or more age groups. Additionally in order to focus on grey literature from underrepresented regions, we undertook a Google Scholar search of gestational diabetes prevalence studies published between 2017 and 2020 relating to 110 low or middle income countries. For each country, we included the highest scoring study according to the IDF methodology criteria as reported in Linnenkamp [2].
Using our updated approach, 48 new studies from 43 countries were identified, a 94% increase from the IDF Atlas selection of 51 studies. 22 studies were identified from countries which were not represented in the IDF Atlas HIP prevalence estimation. Of these, only 10 (20.8%) studies had three or more age groups reported.
A revision of the IDF Atlas methodology is suggested. In allowing studies which do not report three or more age groups would enable newer and higher quality studies to be included in its HIP prevalence estimation.