Objectives To investigate calcium supplement in pregnancy for prevention of preeclampsia and relevant outcomes. Methods The Cochrane Library, PubMed, EMbase, CBM, WanFang Data, VIP and CNKI databases were searched online to collect randomized controlled trials (RCTs) of calcium supplement in pregnancy for prevention of preeclampsia and relevant outcomes from inception to July 2018. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Meta-analysis was then performed by RevMan 5.3 software. Results A total of 33 RCTs involving 29 234 subjects were included. The results of meta-analysis showed that: compared with control group, the calcium supplement group was associated with lower preeclampsia (RR=0.48, 95%CI 0.38 to 0.62, P<0.000 01) and gestational hypertension (RR=0.65, 95%CI 0.55 to 0.77,P<0.000 01) incidence. The incidence of premature delivery, intrauterine growth retardation and severe preeclampsia in calcium supplement group was lower than that in placebo group, and the neonatal weight in calcium was higher than that in placebo group. However, there was no significant difference in the pregnancy cycle between the two groups. Conclusions Current evidence shows that calcium supplement is associated with lower risk of preeclampsia and gestational hypertension. Due to limited quality and quantity of the included studies, more high quality studies are required to verify the above conclusion.
Evidence mapping is a new type of comprehensive evidence research method that systematically collects, evaluates, and synthesizes existing evidence to clarify research status and gaps, thereby promoting scientific research and decision-making. After nearly 20 years of development, the methodology of evidence mapping has been continuously improved, and has gained wide attention and recognition from the international community. China has paid much attention to evidence mapping at an early stage, but there are relatively few theoretical and practical researches, and the concept definition is inconsistent. This paper introduces the methodology of evidence mapping production and reporting for researchers to use for reference, with a view to further promoting the research and development of evidence mapping in China.
目的 探讨脂多糖（LPS）、白细胞介素-6（IL-6）和血小板活化因子（PAF）与重症胸腹创伤后凝血功能紊乱发生的相关性及可能的致病机理。方法 收集2009年1月至2011年12月期间在中国人民解放军第二五三医院急诊科就诊、创伤指数≥17分且除外合并颅脑损伤及在急诊科内死亡的胸腹创伤患者62例，在予以抢救、治疗的同时抽血检查血小板计数（PLT）、血浆D-二聚体（D-D）、部分活化凝血酶原时间（APTT）、凝血酶原时间（PT）、LPS、IL-6和PAF，并对其结果进行相关性分析。结果 本组患者就诊时检测的PLT为（157.73±78.11）×109/L， D-D为（1 023.88±208.72） U/L，APTT为（46.95±17.85） s，PT为（19.44±6.95） s，TT为（58.27±12.44）s，除PLT降低外，其余4项指标均升高或延长； LPS为（322.85±104.54） U/L，IL-6为（285.51±81.46） ng/mL，PAF为 （14 714.70±4 427.95） ng/L， 三者均升高； PLT与LPS、IL-6和PAF之间呈负相关关系（P＜0.001），而D-D、APTT、PT和TT与LPS、IL-6和PAF之间均呈正相关关系（P＜0.001）。结论 LPS、IL-6及PAF可能参与了重症胸腹创伤后凝血功能障碍的发生；重症胸腹损伤后出现的微循环障碍及内毒素血症是凝血功能障碍发生的重要机理。针对LPS、IL-6和PAF进行早期干预，有可能改善重症胸腹创伤患者的凝血功能障碍。