Gestational diabetes linked to ten fold rise in risk of type 2 Diabetes

Researchers have found that gestational diabetes mellitus was associated with 10 fold risk of developing type 2 Diabetes later.This highlights the importance of postpartum screening to identify those at higher risk of progression and introduce strategies for disease prevention.The research has been published in the BMJ today.

They conducted a Systematic review and meta-analysis. to estimate and compare progression rates to type 2 diabetes mellitus (T2DM) in women with gestational diabetes mellitus (GDM) and healthy controls.

They extracted data from Medline and Embase between January 2000 and December 2019, studies published in English and conducted on humans.

All the observational studies investigating progression to T2DM were considered.The inclusion criteria were postpartum follow-up for at least 12 months, incident physician based diagnosis of diabetes, T2DM reported as a separate outcome rather than combined with impaired fasting glucose or impaired glucose tolerance, and studies with both a group of patients with gestational diabetes mellitus and a control group.

This meta-analysis of 20 studies assessed a total of 1 332 373 individuals (67 956 women with GDM and 1 264 417 controls). Data were pooled by random effects meta-analysis models, and heterogeneity was assessed by use of the I2 statistic. The pooled relative risk for the incidence of T2DM between participants with GDM and controls was estimated. Reasons for heterogeneity between studies were investigated by prespecified subgroup and meta-regression analyses. Publication bias was assessed by funnel plots and, overall, studies were deemed to have a low risk of bias (P=0.58 and P=0.90). The overall relative risk for T2DM was almost 10 times higher in women with previous GDM than in healthy controls (9.51, 95% confidence interval 7.14 to 12.67, P<0.001). In populations of women with previous gestational diabetes mellitus, the cumulative incidence of T2DM was 16.46% (95% confidence interval 16.16% to 16.77%) in women of mixed ethnicity, 15.58% (13.30% to 17.86%) in a predominantly non-white population, and 9.91% (9.39% to 10.42%) in a white population. These differences were not statistically significant between subgroups (white v mixed populations, P=0.26; white v non-white populations, P=0.54). The researchers noted that meta-regression analyses showed that the study effect size was not significantly associated with mean study age, body mass index, publication year, and length of follow-up.

The researchers concluded that women with a history of gestational diabetes mellitus appear to have a nearly 10-fold higher risk of developing T2DM than those with a normoglycaemic pregnancy. The magnitude of this risk highlights the importance of intervening to prevent the onset of T2DM, particularly in the early years after pregnancy.

This is consistent with evidence that the two conditions share common pathogenic mechanisms and risk factors,suggesting that gestational diabetes mellitus could potentially serve as a predictor for future development of T2DM.

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BMJ 2020; 369 doi: https://doi.org/10.1136/bmj.m1361