Association between the antepartum oral glucose tolerance test and the risk of future diabetes mellitus among women with gestational diabetes: A systematic review and meta-analysis.

OBJECTIVES:The antepartum oral glucose tolerance test (OGTT) has re-emerged as associated with risk of diabetes among women with gestational diabetes (GDM). This systematic review summarized evidence on associations between antepartum OGTT and risk of diabetes in GDM (PROSPERO CRD42018100316). METHODS:MEDLINE, EMBASE, Web of Science, and CENTRAL were searched from January 1, 1982 to February 2020. Studies assessing associations between antepartum OGTT and risk of diabetes among women with GDM were included. Data on study characteristics, participants, OGTT values, and diabetes outcomes were extracted. Estimates on the association between antepartum OGTT and diabetes at follow-up were recorded. Pooled odds ratios for developing diabetes were calculated by study design. FINDINGS AND CONCLUSIONS:Of 6423 citations, 17 studies were included. Both elevated fasting blood glucose (FBG; OR: 3.62 ([95% CI 1.30, 10.12], I2 = 36%, p < 0.05)) and 2 h OGTT (OR: 3.96 [1.17, 13.40], I2 = 87%, p < 0.05) were associated with diabetes. These associations were attenuated (FBG: OR: 1.91 ([95% CI 0.80, 24.54], I2 = 83%, p = NS) and 1.58 ([95% CI 0.92, 2.74] I2 = 83%, p = NS) for prospective and retrospective data, respectively; 2 h OGTT: ORa: 1.95 ([95% CI 0.43, 8.93], I2 = 94%, p = NS)) after adjustments for common confounders. Further research is needed before clinical recommendations can be made.