Influence of gestational diabetes mellitus on subclinical myocardial dysfunction during pregnancy: A systematic review and meta-analysis

Objective: The correlation between gestational diabetes mellitus (GDM) and subclinical myocardial dysfunction has been poorly investigated. Accordingly, we performed a meta-analysis to examine the influence of GDM on left ventricular (LV) global longitudinal strain (GLS), assessed by speckle tracking echocardiography (STE), during pregnancy. Study design: All echocardiographic studies assessing conventional echoDoppler parameters and LV-GLS in GDM women vs. healthy controls, selected from PubMed and EMBASE databases, were included. The risk of bias was assessed by using the National Institutes of Health (NIH) Quality Assessment of Case-Control Studies. The subtotal and overall standardized mean differences (SMDs) of LV-GLS were calculated using the random-effect model. Results: The full-texts of 10 studies with 1147 women with GDM and 7706 pregnant women without diabetes were analyzed. GDM women enrolled in the included studies were diagnosed with a small reduction in LV-GLS in comparison to controls (average value −19.4 ± 2.5 vs −21.8 ± 2.5 %, P < 0.001) and to the accepted reference values (more negative than −20 %). Substantial heterogeneity was detected for the included studies, with an overall statistic value I2 of 94.4 % (P < 0.001). Large SMDs were obtained for the included studies, with an overall SMD of −0.97 (95 %CI −1.32, −0.63, P < 0.001). Egger's test for a regression intercept gave a P-value of 0.99, indicating no publication bias. On meta-regression analysis, all moderators and/or potential confounders (age at pregnancy, BMI, systolic blood pressure and ethnicity) were not significantly associated with effect modification (all P < 0.05). Conclusions: GDM is independently associated with subclinical myocardial dysfunction in pregnancy. STE analysis allows to identify, among GDM women, those who might benefit of targeted non-pharmacological and/or pharmacological interventions, aimed at reducing the risk of developing type 2 diabetes and cardiovascular complications later in life.