Association between asymmetric dimethylarginine level and preeclampsia: a meta-analysis

Inconsistent results existed between the circulating asymmetric dimethylarginine (ADMA) concentration and preeclampsia. This meta-analysis aimed to compare the circulating ADMA concentration in patients with preeclampsia and healthy pregnant women. A systematic literature search was performed in PubMed, Embase, CNKI, VIP, and Wanfang database up to May 30, 2016. Case-control studies reporting the circulating ADMA concentration in preeclampsia patients and healthy pregnant women were selected. The pooled standard mean difference (SMD) with 95% confidence interval (CI) were used to estimate the relationship between circulating ADMA concentration and preeclampsia. Eighteen studies involving 879 preeclampsia patients and 994 healthy pregnant women were identified and analyzed. The pooled estimates from 11 studies showed that preeclampsia patients had an increased circulating ADMA concentration as compared with healthy pregnant women (SMD=1.15; 95% CI=0.75-1.55). Subgroup analysis indicated that the association was more pronounced in severe preeclampsia patients (SMD=2.41; 95% CI=1.43-3.39) than in the mild preeclampsia patients (SMD=1.62; 95% CI=0.52-2.71). The meta-analysis suggests that higher circulating ADMA concentration was observed to be higher in women with preeclampsia than that in the healthy pregnant controls. Elevated ADMA concentration is positively correlated to the severity of disease.