Bashash Davood, Hosseini-Baharanchi Fatemeh Sadat, Rezaie-Tavirani Mostafa, Safa Majid, Akbari Dilmaghani Nader, Faranoush Mohammad, Abolghasemi Hassan
Department of Hematology and Blood Banking, School of Allied Medical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Minimally Invasive Surgery Research Center & Department of Biostatistics, School of Public Health, Iran University of Medical Sciences, Tehran, Iran.
Arch Acad Emerg Med. 2020 Sep 19;8(1):e75. eCollection 2020.
Multiple lines of evidence have attested that decreased numbers of platelets may serve as a surrogate marker for poor prognosis in a wide range of infectious diseases. Thus, to provide a well-conceptualized viewpoint demonstrating the prognostic value of thrombocytopenia in COVID-19, we performed a meta-analysis of pertinent literature.
The keywords "platelet" OR "thrombocytopenia" AND "COVID-19" OR "coronavirus 2019" OR "2019-nCoV" OR "SARS-CoV-2" were searched in National Library of Medicine Medline/PubMed and Scopus between December 30, 2019, and May 9, 2020 in English without any restriction. The initial search results were first screened by title and abstract, and then full texts of relevant articles representing information on the platelet count (main outcome) with a clinically validated definition of COVID-19 severity were finally selected. To assess the existence of bias in the included studies, the funnel plot and egger plot along with egger tests were used. Also, the heterogeneity among the included studies was tested using the Chi-square test.
The results of our meta-analysis of 19 studies, totaling 3383 COVID-19 patients with 744 (21.9%) severe cases, revealed that non-severe cases have a significantly higher number of platelets and showed that the probability of the emergence of thrombocytopenia is significantly higher in the severe cases with the pooled mean difference of -21.5 (%95 CI: -31.57, -11.43).
Decreased number of platelets more commonly associates with severe COVID-19; however, whether the emergence of thrombocytopenia may result in diseases severity or the severity of the disease may decrease platelets, is open to debate.
多条证据表明，血小板数量减少可能是多种传染病预后不良的替代指标。因此，为了提供一个能充分说明血小板减少在新型冠状病毒肺炎（COVID-19）中预后价值的概念清晰的观点，我们对相关文献进行了荟萃分析。
于2019年12月30日至2020年5月9日期间，在无任何限制的情况下，使用英文在国立医学图书馆Medline/PubMed和Scopus数据库中检索关键词“血小板”或“血小板减少症”以及“COVID-19”或“2019冠状病毒病”或“2019-nCoV”或“严重急性呼吸综合征冠状病毒2型（SARS-CoV-2）”。初始检索结果首先通过标题和摘要进行筛选，然后最终选择代表具有经临床验证的COVID-19严重程度定义的血小板计数（主要结局）信息的相关文章全文。为评估纳入研究中是否存在偏倚，使用了漏斗图和埃格检验以及埃格图。此外，使用卡方检验对纳入研究之间的异质性进行了检验。
我们对19项研究进行荟萃分析的结果显示，共有3383例COVID-19患者，其中744例（21.9%）为重症病例；结果表明，非重症病例血小板数量显著更高，且重症病例出现血小板减少症的概率显著更高，合并平均差为-21.5（95%置信区间：-31.57, -11.43）。
血小板数量减少更常见于重症COVID-19；然而血小板减少症是否导致疾病严重程度增加，或者疾病严重程度是否导致血小板数量减少，仍有待讨论。
