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血小板计数可预测HIV阴性涂阳肺结核住院患者的院内死亡

We reviewed patients who were treated by the isoniazid, rifampicin, pyrazinamide, and ethambutol regimen or by the isoniazid, rifampicin, and ethambutol regimen. 

The association between the patient data on admission and the survival outcome was evaluated.

我们回顾了采用异烟肼、利福平、吡嗪酰胺和乙胺丁醇治疗方案或采用异烟肼、利福平和乙胺丁醇治疗方案的患者。

评估患者入院数据和生存结果之间的关系。

Some risk factors for death from TB have already been revealed, these include old age, dehydration, respiratory failure, decreased activity of daily living, and malnutrition . 

However, much still remains to be clarified.

结核病死亡的一些风险因素已经被揭示，这些因素包括老年、脱水、呼吸衰竭、日常生活活动减少和营养不良。

然而，仍有许多问题有待澄清。

Although the blood cell count has different meanings depending on the clinical background, leukocytosis most commonly implies elevated inflammation due by bacterial infection, while a decreased hemoglobin level suggests iron deficiency and chronic inflammation, and a low platelet count indicates a high risk of bleeding. 

In addition, recent studies have revealed that―in addition to white blood cells - platelets are involved in the defense mechanism . 

Thus, a low platelet count might indicate the lack of a proper immune system.

尽管血细胞计数根据临床背景有不同的含义，白细胞增多通常意味着细菌感染引起的炎症升高，而血红蛋白水平降低则提示铁缺乏和慢性炎症，血小板计数低则提示出血风险高。

此外，最近的研究表明，除了白细胞外，血小板也参与了防御机制。

因此，低血小板计数可能表明缺乏适当的免疫系统。

To the best our knowledge, this is the first study to evaluate whether the three components of the blood cell count have prognostic implications in HIV-negative Japanese inpatients with smear-positive pulmonary TB. 

Among the three components, the platelet count was the only marker that predicted in-hospital death.

据我们所知，这是第一个评估血细胞计数的三种成分是否对艾滋病毒阴性的日本涂片阳性肺结核住院患者有预后影响的研究。

在这三种成分中，血小板计数是唯一预测院内死亡的指标。

Our observational study cannot directly answer why a low platelet count is associated with a high risk of death. 

One possibility is that a decreased platelet count indicates a decreased liver function. 

The platelet count may be a confounding factor between the liver function and TB death. 

The liver is a vital organ for nutrition storage, albumin synthesis, and drug metabolism. 

Actually, in the analysis of this study, some liver-related laboratory tests (i.e., total bilirubin, albumin, and aspartate aminotransferase) were included in the final Cox model. 

Among these factors, a low albumin level was found to be a key risk factor of TB death. 

Thus, our primary hypothesis is that a decreased platelet count is a surrogate marker for the liver function and nutrition.

我们的观察性研究不能直接回答为什么低血小板计数与高死亡风险相关。一种可能是血小板计数下降表明肝功能下降。

血小板计数可能是肝功能和肺结核死亡之间的一个混杂因素。

肝脏是储存营养、合成白蛋白和药物代谢的重要器官。

实际上，在本研究的分析中，一些肝脏相关的实验室检测(总胆红素、白蛋白、天冬氨酸转氨酶)被纳入最终的Cox模型。

在这些因素中，低白蛋白水平被发现是结核病死亡的关键危险因素。

因此，我们的主要假设是血小板计数下降是肝功能和营养的替代标志。

Another credible explanation for the link between the low platelet count and a high risk of death is that the platelet count can work as a marker of the defense mechanism to TB bacilli in the lung. 

Direct phagocytosis of invading particles and bacilli is one of the defense mechanisms used by platelets.

In addition, platelets activate cytotoxic T lymphocytes. 

Platelets also release antibacterial protein, thrombocidins, which are lethal to a range of bacteria. 

Furthermore, platelets activate the immune system of the lungs via numerous cytokines. 

In vivo studies have revealed that the platelet count and platelet factor level are elevated in TB patients, especially in cases with extensive pulmonary infiltration. 

A decreased platelet count may indicate a decreased defense against co-morbid infection.

对于低血小板计数和高死亡风险之间的联系，另一种可信的解释是血小板计数可以作为肺内结核杆菌防御机制的标记物。血小板直接吞噬入侵颗粒和细菌是其防御机制之一。

此外，血小板还能激活细胞毒性T淋巴细胞。血小板还会释放抗菌蛋白和凝血素，这对一些细菌是致命的。

此外，血小板通过多种细胞因子激活肺部的免疫系统。

体内研究表明，结核患者的血小板计数和血小板因子水平升高，特别是在广泛肺浸润的病例中。

血小板计数减少可能表明对合并感染的防御能力降低。

A low platelet count usually suggests a risk of bleeding. Thus, platelet transfusion was indicated for a patient with platelet count of <20,000/μL. 

However, the patients in our cohort did not die of major bleeding due to a low platelet count. In all of the fatal cases, the patients had a platelet count over 20,000/μL at admission . 

Furthermore, only one patient who died from major bleeding had a platelet count of 172,000/μL at admission. 

Thus, we do not think that bleeding caused by low platelet count was the main reason for in-hospital death.

低血小板计数通常表明有出血的风险。因此，血小板计数< 20000 /μL的患者需要输血。

然而，在我们的队列中，患者并没有死于血小板计数低的大出血。在所有的死亡病例中，患者入院时血小板计数超过20000 /μ。

此外，只有一名因大出血死亡的患者入院时血小板计数为172000 /μL。

因此，我们不认为低血小板计数引起的出血是住院死亡的主要原因。

The present study was associated with some limitations. 

First, it was retrospective in nature, which might have induced bias. However, we believe that this simple study using a hard endpoint was not strongly biased by the study design. 

Second, our TB cohort mainly consisted of elderly individuals that reflected the East Asian epidemiology .Thus, the findings should be validated in other cohorts, especially cohorts with younger patients, in the future. 

Third,our data showed that a low platelet count was related to TB death. 

However, the true causative factor of death among the patients with low-platelet counts was unclear.

目前的研究有一些局限性。

首先，它本质上是回顾性的，这可能会导致偏见。然而，我们相信这个使用硬终点的简单研究在研究设计上没有强烈的偏见。

第二，我们的结核病队列主要由老年人组成，反映了东亚流行病学。因此，这一发现应该在未来的其他队列中得到验证，特别是年轻患者队列。

第三，我们的数据显示血小板计数低与结核病死亡有关。

然而，低血小板计数患者死亡的真正原因尚不清楚。

Eventually, our results showed that a low platelet count was clearly related to a poor life prognosis in the patients of the present study.

最终，我们的结果显示低血小板计数明显与本研究患者不良的生活预后相关。