摘要目的:探讨血小板计数（platelet count, PLT）与危重患者器官功能障碍和预后的关系，评价预后评估中的价值。方法:采用回顾性队列研究的方法，收集美国重症监护数据库（MIMIC-Ⅲ）中2001年至2012年的35 860例患者的相关记录。依据PLT将患者分为PLT减少组（PLT<100×10 9/L）、PLT正常组（100×10 9/L≤PLT≤300×10 9/L）和PLT增多组（PLT>300×10 9/L）。本研究纳入18岁以上且89岁以下的成年患者，排除存活时间少于24 h、缺失生命体征记录或PLT的患者。结局事件为患者住院死亡。采用Kaplan-Meier方法分析存活率，单因素和多因素COX回归分析指标对预后的影响。结合重要的预后因素建立列线图以预测重症患者住院预后情况，并应用ROC曲线下面积（AUC值）评估列线图辨别力。 结果:与PLT正常组及PLT增多组比较，PLT减少组患者的器官功能障碍明显加重，患者的SOFA评分[3（2，5） vs. 2（1，5） vs. 7（5，9）]、SAPS-Ⅱ评分[31（23，41） vs. 32（23，42） vs. 38（30，50）]、住院病死率（35.0% vs. 45.2% vs. 54.7%）、机械通气率（50.3% vs. 41.4% vs. 62.8%）和肾脏替代治疗率（1.3% vs. 1.3% vs. 6.0%）均明显更高（均 P<0.05）。COX回归分析发现PLT减少是住院患者病死率的独立预测因子，PLT<100×10 9/L的风险比为1.477，95% CI为1.347~1.691， P<0.01。以上述指标构建列线图，列线图的AUC为0.744。 结论:PLT减少是影响重症患者住院死亡的独立预后指标。PLT相关的列线图有良好的区分度，有可能帮助临床医生评估住院患者预后结局。

abstractsObjective:To explore the relationship between platelet count (PLT) and organ dysfunction and prognosis in critically ill patients and its prognostic evaluation.Methods:A retrospective cohort study was conducted. The relevant records of 35 860 patients were extracted from the US Intensive Care Database (MIMIC-Ⅲ) from 2001 to 2012. According to the PLT count, patients were divided into the thrombocytopenia group (PLT<100×10 9/L), normal platelet group (100×10 9/L≤PLT≤300×10 9/L), and thrombocytosis group (PLT>300×10 9/L). This study included adult patients between 18 and 89 years old. Patients with survival time less than 24 h and lack of vital signs or PLT values were excluded. The outcome event was the hospital mortality of the patient. Survival was analyzed by the Kaplan-Meier method. The prognostic factors were identified by univariate and multivariate COX analyses. The nomogram to predict hospital mortality was built by the significant prognostic factors. In combination with the important prognostic factors, a nomogram was established to predict the prognosis of critically ill patients in hospital, and the AUC value under the ROC curve was used to assess the discriminative power of the nomogram. Results:Compared with the normal PLT group and the thrombocythemia group, organ dysfunction in the thrombocytopenia group was significantly worse; the SOFA score [3 (2, 5) vs. 2.0 (1, 5) vs. 7 (5, 9)], SAPS-Ⅱ score [31 (23, 41) vs. 32 (23, 42) vs. 38 (30, 50) ], hospital mortality (35.0% vs. 45.2% vs. 54.7%), the incidence of mechanical ventilation (50.3% vs. 41.4% vs. 62.8%), and renal replacement therapy (1.3% vs. 1.3% vs. 6.0%) were significantly higher (all P<0.05). COX regression analysis found that thrombocytopenia was an independent predictor of hospital mortality and was entered into a nomogram after final regressions ( HR=1.477, 95% CI: 1.347-1.691, P<0.01). When the above indicators were brought into the nomogram, the AUC of the nomogram was 0.744. Conclusions:Thrombocytopenia is an independent prognostic predictor of hospital mortality for critically ill patients. PLT-related nomograms have good discrimination, which may help clinicians evaluate the prognosis of hospitalized patients.