Читать книгу Gestational Diabetes - Группа авторов - Страница 61

In order to determine diagnostic thresholds, the primary preparatory step is to select the related outcome to be associated with the cutoff. Among the 4 primary and 5 secondary outcomes, the strongest linear associations were between LGA babies, cord C-peptide, and neonatal adiposity with each of the 75 g OGTT values [18]. Therefore, as O’Sullivan chose postpartum T2DM, the IADPSG consensus panel chose the associations with these 3 outcomes – and primarily LGA. Other than their strong associations to glucose values, they are important and clinically relevant constituents of diabetic fetopathy. This approach was supported not only by the HAPO results but also by previous publications that have established that LGA and fetal macrosomia are correlated to gestational hyperglycemia and independently associated with cesarean delivery, neonatal adiposity, fetal hyperinsulinemia, and birth trauma [53–58].

Nevertheless, the choice of these outcomes sustained major criticism, claiming that the selected outcomes are not the true clinically important outcome that should guide the diagnosis. Rather, LGA is a surrogate marker to difficult delivery and future maternal and offspring metabolic anomalies. Also, there is no long-term follow-up to determine if these LGA babies are indeed at an increased risk for metabolic complications, and no proof that reducing macrosomia will result in long-term benefits [35–37] – a point that will change once the long-term HAPO follow-up study will be published.

Other possible outcomes produced much more modest risk ratio (RR) – neonatal hypoglycemia (1.18 for the 2-h plasma glucose to 1.24 for the FPG), shoulder dystocia, and/or birth injury (1.3 for the FPG to 1.43 for the 2 h) or preeclampsia (1.4 for the FPG to 1.57 for the 2 h). Such RRs are far from useful to discriminate between the healthy and the sick with GDM.

Therefore, although it is questionable whether the choice of LGA as an outcome is adequate and clinically relevant, it is without doubt the best yet outcome, and with possible long-term relevancy, as unpublished data from the HAPO follow-up suggest.