Risk of type 2 diabetes mellitus after gestational diabetes mellitus: A systematic review & meta-analysis

Abstract

Background &objectives: Women with gestational diabetes are at an increased risk of being diagnosed as type 2 diabetes, but the postpartum screening rate is low. To provide evidence-based data for health providers and promote postpartum screening, this systematic review and meta-analysis was conducted to access the risks of type 2 diabetes mellitus (T2DM) diagnosis after gestational diabetes mellitus (GDM) in different demographic and maternal subgroups.

Methods: MEDLINE, Embase and Cochrane Library were searched systematically. Unadjusted relative risks (RRs) and 95 per cent confidence intervals (CIs) were calculated and pooled using a random-effects model. Heterogeneity was assessed with Cochrane's Q text and by calculating I² values. Subgroup analyses were conducted to address the disparities of type 2 diabetes conversion after gestational diabetes in different demographic and maternal subgroups.

Results: 1809 publications were screened and 39 cohort studies including 2,847,596 women were selected. In these studies, 78,893 women were diagnosed as T2DM at six weeks or later after delivery. The unadjusted RRs of women diagnosed T2DM at six weeks or later after delivery ranged from 1.32 (95% CI, 0.46-3.37) to 47.25 (95% CI, 2.95-758.01) with a pooled unadjusted RR of 8.92 (95% CI, 7.84-10.14). Older women, women with a family history of diabetes, Black and non-Hispanic White women and women living in Europe and South-East Asia had a higher risk of developing T2DM after GDM.

Interpretation & conclusions: It is suggested that healthcare providers may focus on older women with GDM and women with GDM and a family history of diabetes. Black and non-Hispanic White women with GDM may receive more attention, and healthcare providers, especially those in Europe and South-East Asia, may pay more attention to preventive measures for postpartum T2DM.

Keywords: Blood glucose; OGTT screening; gestational diabetes mellitus; postpartum; type 2 diabetes mellitus.

Fig. 1

PRISMA flow diagram showing literature search.

Fig. 2

Newcastle–Ottawa Scale scores of 39 included studies in meta-analysis.

Fig. 3

Forest plot of the risk of women diagnosed as type 2 diabetes mellitus (DM) after gestational DM. X-axis is plotted in log scale. Solid squares and horizontal lines indicate relative ratios and 95 per cent confidence intervals. The diamond represents the pooled relative risk (RR).

Fig. 4

Sensitivity analysis of women diagnosed as type 2 DM after gestational DM. Three vertical lines indicate the pooled RR and 95 per cent CI of all studies. Circles and horizontal dashed lines indicate recalculated RRs and 95 per cent CIs.

Fig. 5

Risk of women diagnosed as type 2 DM after gestational diabetes mellitus grouped by maternal characteristics, study characteristics and diagnostic criteria. The diamond represents the subtotal relative risk.

Fig. 6

Begg’s funnel plot of 39 publications.

Fig. 7

Egger’s publication bias plot of 39 publications.