降钙素：用于败血症诊断的系统评价和META分析

蓝鱼o_0

Lancet Infect Dis. 2013 Jan 31. pii: S1473-3099(12)70323-7. doi: 10.1016/S1473-3099(12)70323-7. [Epub ahead of print]
Procalcitonin as a diagnostic marker for sepsis: a systematic review and meta-analysis.Wacker C, Prkno A, Brunkhorst FM, Schlattmann P.
SourceDepartment of Medical Statistics, Computer Sciences and Documentation, Centre for Sepsis Control and Care, Jena University Hospital, Jena, Germany.

AbstractBACKGROUND: Procalcitonin is a promising marker for identification of bacterial infections. We assessed the accuracy and clinical value of procalcitonin for diagnosis of sepsis in critically ill patients.
METHODS: We searched Medline, Embase, ISI Web of Knowledge, the Cochrane Library, Scopus, BioMed Central, and Science Direct, from inception to Feb 21, 2012, and reference lists of identified primary studies. We included articles written in English, German, or French that investigated procalcitonin for differentiation of septic patients-those with sepsis, severe sepsis, or septic shock-from those with a systemic inflammatory response syndrome of non-infectious origin. Studies of healthy people, patients without probable infection, and children younger than 28 days were excluded. Two independent investigators extracted patient and study characteristics; discrepancies were resolved by consensus. We calculated individual and pooled sensitivities and specificities. We used I(2) to test heterogeneity and investigated the source of heterogeneity by metaregression.
FINDINGS: Our search returned 3487 reports, of which 30 fulfilled the inclusion criteria, accounting for 3244 patients. Bivariate analysis yielded a mean sensitivity of 0·77 (95% CI 0·72-0·81) and specificity of 0·79 (95% CI 0·74-0·84). The area under the receiver operating characteristic curve was 0·85 (95% CI 0·81-0·88). The studies had substantial heterogeneity (I(2)=96%, 95% CI 94-99). None of the subgroups investigated-population, admission category, assay used, severity of disease, and description and masking of the reference standard-could account for the heterogeneity.
INTERPRETATION: Procalcitonin is a helpful biomarker for early diagnosis of sepsis in critically ill patients. Nevertheless, the results of the test must be interpreted carefully in the context of medical history, physical examination, and microbiological assessment.
FUNDING: Ministry of Education and Research, the Deutsche Forschungsgemeinschaft, Thuringian Ministry for Education, Science and Culture, the Thuringian Foundation for Technology, Innovation and Research, and the German Sepsis Society.
Copyright © 2013 Elsevier Ltd. All rights reserved.

蓝鱼o_0

降钙素检测常常用于辅助败血症的诊断，然而其临床灵敏度，特异度如何？如何引导临床尚研究不足。最新的柳叶刀综述了3487份报告，发现降钙素检测诊断败血症的灵敏度为0.77，特异度也仅为0.79。无疑提示临床医生在应用此指标诊断时，应谨慎。

蓝鱼o_0

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蓝鱼o_0

灵敏度和特异度是流行病学筛检中，或者诊断中的专业术语。大家也许不太了解。我来简单普及一下。

蓝鱼o_0

灵敏度和特异度是统计学中用来表征二项分类测试特征的数据。其中灵敏度是真阳性与真阳性+假阴性的比值；特异度是=真阴性与真阴性+假阳性的比值。

在一个100人的样本中，有10人事实上患有A病（阳性），经过检测后，9人确定患有A病（真阳性），而1人确定并不患有A病（假阴性）； 另外的90人中事实上并不患有A病（阴性），然后经过检测后，其中的5人被确定患有A病（假阳性），另外的85人确定不患有A病（真阴性）。
灵敏度=真阳性/（真阳性+假阴性）=9/(9+1)=90%;
特异度=真阴性/（真阴性+假阳性）=85/(85+5)=94.4%.
此处，灵敏度即为在患病人群中，成功确证患病的概率；而特异度即为在不患病的人群中，成功排除患病的概率。

蓝鱼o_0

除此之外还有几个重要的指标，阳性预测值，阴性预测值，约登指数，假阳性率，假阴性率。

很容易混淆但又非常重要的概念。

四叶草

多谢蓝鱼超版对j降钙素元筛查败血症的及时报道。看到灵敏度和特异度尾0.77和0.79，个人觉得这个数值应该不错啊，血培养的阳性率才10%左右，至少，目前，还没有比这更灵敏的指标了。不知对否？

缭绕

蓝鱼o_0 发表于 2013-2-7 11:02

                               
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降钙素检测常常用于辅助败血症的诊断，然而其临床灵敏度，特异度如何？如何引导临床尚研究不足。最新的柳叶 ...

灵敏度为0.77，特异度也仅为0.79。无疑提示临床医生在应用此指标诊断时，应谨慎。，请蓝鱼斑斑再介绍一下，临床医生如何读懂这2个值？一项指标要灵敏度和特异性兼得，有点难。如何取舍呢？

宁静的夏天

很可惜这个研究中剔除了新生儿病例，在工作中我们也发现PCT-Q高的新生儿不一定问题很大，但败血症的孩子PCT-Q往往比较高，版主这样文章倒是提醒了我去翻阅一下以往的病例做一下分析。

另外一片荟萃分析

Accuracy of procalcitonin for sepsis diagnosis in critically ill patients: systematic review and meta-analysis.[size=0.923em]Tang BM, Eslick GD, Craig JC, McLean AS.
[size=0.8465em]Source

Department of Intensive Care Medicine, Nepean Hospital, Penrith, New South Wales, Australia. McleanA@wahs.nsw.gov.au

Abstract

Procalcitonin is widely reported as a useful biochemical marker to differentiate sepsis from other non-infectious causes of systemic inflammatory response syndrome. In this systematic review, we estimated the diagnostic accuracy of procalcitonin in sepsis diagnosis in critically ill patients. 18 studies were included in the review. Overall, the diagnostic performance of procalcitonin was low, with mean values of both sensitivity and specificity being 71% (95% CI 67-76) and an area under the summary receiver operator characteristic curve of 0.78 (95% CI 0.73-0.83). Studies were grouped into phase 2 studies (n=14) and phase 3 studies (n=4) by use of Sackett and Haynes' classification. Phase 2 studies had a low pooled diagnostic odds ratio of 7.79 (95% CI 5.86-10.35). Phase 3 studies showed significant heterogeneity because of variability in sample size (meta-regression coefficient -0.592, p=0.017), with diagnostic performance upwardly biased in smaller studies, but moving towards a null effect in larger studies. Procalcitonin cannot reliably differentiate sepsis from other non-infectious causes of systemic inflammatory response syndrome in critically ill adult patients. The findings from this study do not lend support to the widespread use of the procalcitonin test in critical care settings.

蓝鱼o_0

缭绕 发表于 2013-2-7 14:27

                               
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灵敏度为0.77，特异度也仅为0.79。无疑提示临床医生在应用此指标诊断时，应谨慎。，请蓝鱼斑斑再介绍一下 ...

个人体会，这个灵敏度和特异度均不是很高。所以柳叶刀这篇文章结论下的非常保守。
您说的很正确，灵敏度和特异度是矛盾的，一个大，另一个将会小点。如何选择？
这要看具体的临床目的，比如我是筛检MRSA，那就必须提高灵敏度，因为我的目的是将真阳性的患者筛选出来。
降钙素检测也是，发现或者暴露出败血症或者潜在败血症的****。

在本研究中，灵敏度，特异度并不高，怎么办呢？
通常情况下，是需要2个或者2个以上的诊断方法，串联或者并联实验。通常并联实验提高灵敏度，串联实验用于提高特异度。

缭绕

蓝鱼o_0 发表于 2013-2-7 17:12

                               
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个人体会，这个灵敏度和特异度均不是很高。所以柳叶刀这篇文章结论下的非常保守。
您说的很正确，灵敏度 ...

谢谢蓝鱼的解释，我愿意用自己的无知逐步引导蓝鱼将这个话题解释透来
已经发布到新浪微博上。
很多学术会议上是很推崇做PCT的。这篇文章无疑是一盆冷水呃！

蓝鱼o_0

缭绕 发表于 2013-2-7 20:45

                               
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谢谢蓝鱼的解释，我愿意用自己的无知逐步引导蓝鱼将这个话题解释透来
已经发布到新浪微博 ...

缭绕老师，您过谦了。小鱼不才，也是浅尝则止。

xzzlhhy

谢谢各位老师的传授，我们都受益了很多

zzregister

学习了！ 不错！！！！！！！！！！