Poster Australasian Diabetes in Pregnancy Annual Scientific Meeting 2013

Follow-up after gestational diabetes (GDM): whom are we missing? (#123)

Sue Lynn Lau 1 2 , Allsion Sigmund 1 2 , Jane Zhang 1 , Susan Hendon 1 , Tien-Ming Hng 1 , Mark McLean 1 2
  1. Blacktown Hospital, Blacktown, NSW, Australia
  2. University of Western Sydney, Sydney

Background: Studies examining risk and predictors of glucose intolerance post-GDM rely on retrospective data, or following longitudinal cohorts. Early gestational age at diagnosis, higher antepartum OGTT values and greater BMI confer greater risk of subsequent diabetes1 . However, data from women who fail to attend follow-up (around 50%2), or decline participation in longitudinal studies, are missed. It is not clear whether these women represent a group at lower/higher risk of glucose intolerance and thus whether studies over/underestimate subsequent risk.

Methods: From September 2012, women attending the GDM clinic were invited to participate in a longitudinal follow-up study. Those with pre-gestational diabetes(22), minimal English proficiency(10) and non-residents(4) were excluded. Women who returned consent were booked for OGTT at 6-12 weeks postpartum.  Women who did not return consent were advised to have follow-up OGTT, and given the option of booking it at our centre. Demographic and medical details of study-consenters versus non-consenters and OGTT-attendees versus non-attendees were compared.

Results: 120 of 232 women returned consent for the longitudinal study. There were no significant differences in mean age (31.8 vs 32.5yrs), gestational age at GDM-diagnosis (24wks) or booking-in BMI (29 both groups) between those who did or did not return consent forms. Mean fasting/2hr BGL on antepartum OGTT was identical in both groups (5.1/8.9mmol/L), as was mean 3rd trimester HbA1c (5.5%). Of 112 study non-consenters, 26 completed, 26 failed to attend and 29 await postpartum OGTT. 31 are lost to follow-up. Of 120 study-consenters, 54 completed, 36 failed to attend and 30 await OGTT. Comparing 80 GTT-attendees with 62 who failed to attend, attendees were older (mean 33 vs 31yrs, p=0.01), but there was no difference in gestational age at diagnosis, antepartum OGTT or BMI. Previous history of GDM did not affect OGTT attendance (14% both groups), nor was there any difference in delivery mode, parity, insulin-use or proportion of overseas-born women (71 vs 61%, p=0.28).

Conclusions: Antepartum characteristics known to predict higher diabetes risk were not significantly different in non-study participants and non-attendees for postpartum OGTT. Non-attendance rates are high; further exploring predictors and reasons for non-attendance would enable design of strategies that improve follow-up.

  1. M.Albareda et al. Diabetes and abnormal glucose tolerance in women with previous gestational diabetes. Diab Care 2003:26(4);1199-205
  2. C.Chittleborough et al. Long-term follow-up of women with gestational diabetes mellitus: the South Australian Gestational Diabetes Mellitus Recall Register. ANZJOG 2010;50(2):127-31.