Predefined outcomes
Outcome measures were predefined during the design of the present systematic review. Data extraction was performed using a modified data form that was based in Cochrane‘s data collection form for intervention reviews for RCTs and non-RCTs [15]. Investigated outcomes were predetermined based in our previous systematic review that examined the role of serum uric acid as a predictive factor of preeclampsia [16]. Briefly, the main outcome of interest was the comparison of serum LDH levels among preeclamptic and healthy pregnant women in all gestational trimesters.
The prognostic role of uric acid was planned to be evaluated by comparing its levels among women with mild and severe preeclampsia, as well as with eclampsia and HELLP (hemolysis, elevated liver enzymes and low platelet count) syndrome. The diagnostic accuracy of serum uric acid in terms of predicting adverse perinatal outcomes (rate of cesarean section, fetal growth restriction, low birth weight, preterm birth, 5’ Apgar score <7, fetal or neonatal death) was also evaluated.