Serum LDH values in hypertensive disorders of pregnancy and their association with maternal and neonatal morbidity: a meta-analysis

Abstract

Objectives: Serum lactate dehydrogenase has been extensively studied in\nhypertensive disorders of pregnancy. However, to date, its clinical\nusefulness in the field remains unknown. The present meta-analysis has\nbeen designed to evaluate differences in serum LDH values among patients\nwith hypertensive disorders of pregnancy and to help determine its\ndiagnostic accuracy as well its predictive accuracy in determining\nadverse pregnancy outcomes. Methods: We searched Medline, Scopus,\nClinicaltrials.gov, EMBASE, Cochrane Central Register of Controlled\nTrials CENTRAL and Google Scholar databases from their inception till\nMarch 18, 2021. Meta-analysis was performed using the meta and metafor\nfunctions in Rstudio. Pooled mean differences (MD) were calculated with\nthe Hartung-Knapp-Sidik-Jonkman. Meta-regression analyses, publication\nbias assessment and Trim and Fill function were also performed. The\nadequacy of the sample size was evaluated with Trial Sequential\nAnalysis. Results: Fifty-two articles were included that comprised 5,340\nwomen with hypertensive disorders of pregnancy and 2,890 healthy\ncontrols. The meta-analysis revealed significant differences among\npatients with preeclampsia (either mild or severe) compared to controls,\nas well as among patients with mild and severe preeclampsia. Significant\nasymmetry was noted after examining funnel plots, however, and the trim\nand fill analysis revealed that differences were significant only among\ncases with severe preeclampsia and healthy controls. Morbidity outcomes\nincreased with LDH levels > 600 IU/L and particularly when\nthese exceeded 800 IU/L. However, confidence and prediction intervals\nindicated an underpowered sample size for the accurate determination of\nthe odds of developing maternal morbidity. Conclusions: Despite the\nextensive research in the field of hypertensive disorders of pregnancy,\nthere is still lack of evidence concerning the diagnostic performance of\nserum LDH in clinical practice; hence, research should expand in this\ndirection to evaluate its clinical utility.