Contribution of Low-Severity Gestational Diabetes Mellitus on the Diabetes Epidemic

Women with lower-severity gestational diabetes (GDM) may be at risk of developing type 2 diabetes (T2D) postdelivery and may represent the majority of women diagnosed with T2D onset by 3 years post-GDM, contributing to the overall T2D epidemic, according to a study published in Preventive Medicine. 

Researchers conducted an analysis as a secondary inquiry with data acquired from a larger, national, longitudinal de-identified system to identify whether GDM severity influenced postpartum glucose testing or other type of glucose testing outcome by 1 and 3 years postdelivery.

The purpose of the study was to assess the risk of developing early-onset T2D and find the number of cases of T2D caused by severity of GDM.

In addition, researchers attempted to determine what the results of risk calculators, relative risk (RR) vs population attributable fraction, suggest for the contribution of GDM in this patient population. A total of 12,622 continuously insured women with no prior history of T2D were included in the study and placed into 2 categories: women with lower risk for T2D onset with lower GDM severity during pregnancy (n=9995) or women with a higher risk with higher GDM severity during pregnancy (n=2627).

Study results found women with more severe GDM were twice as likely to have an oral glucose tolerance test postpartum, a glucose test by 1 year postdelivery, and glucose testing by 3 years postdelivery compared with women identified as having lower-severity GDM (5.5%, 3.0%, RR 1.83; 32.9 vs 18.8%, RR 1.75; 61.6% vs 48.2%, RR 4.34, respectively).

More women with higher-severity GDM were observed to have a diagnosis of T2D in the 3 years after delivery compared with those with lower-severity GDM (13.6% vs 6.0%, RR 2.26; 95% CI 2.00-2.56).

Interestingly, in the higher-severity category, fewer women were diagnosed with T2D by 3 years postdelivery compared with women in the lower-severity category who were diagnosed with early onset T2D (357 vs 600, respectively) despite having a higher RR than those with lower-severity GDM. The attributable fractions to T2D onset during the 3 years postdelivery follow-up were found to be 21% and 79% for women with higher-risk severity and lower-risk severity.

Researchers concluded that there was an almost 4 times higher risk of developing T2D in women with less-severe GDM during the 3-year postpartum follow-up, contributing significantly to the diabetes epidemic. This study emphasizes the importance of close follow-up in women with less-severe GDM, not just in women diagnosed with high-severity GDM. Clinicians should consider closely following all women identified as having either high or low severity GDM with interventions such as screening and home glucose testing as prevention measures recommended by the American Diabetes Association and the American College of Obstetricians and Gynecologists.

Reference

Bernstein J, Quinn E, Ameli O, et al.  Onset of T2DM after gestational diabetes: What the prevention paradox tells us about risk. Prev Med. 2018;113:1-6.