Chalmers James D, Singanayagam Aran, Hill Adam T
Department of Respiratory Medicine, Royal Infirmary of Edinburgh, Edinburgh, Scotland, UK.
Am J Med. 2008 Mar;121(3):219-25. doi: 10.1016/j.amjmed.2007.10.033.
C-reactive protein (CRP) is an acute phase protein synthesized by the liver primarily in response to interleukin-6. Initial studies have suggested that inflammatory markers may have a role in predicting severity. We investigated whether admission and day 4 CRP could predict severity in community-acquired pneumonia.
A prospective study was carried out over a 2-year period in a large teaching hospital. CRP was measured on admission and on day 4. The outcomes of interest were: 30-day mortality; need for mechanical ventilation and/or inotropic support; development of complicated pneumonia (lung abscess, empyema, or complicated parapneumonic effusion); the value of predictive tests were assessed using multivariate logistic regression.
There were 570 patients included in the study; 30-day mortality was 9.6%. Low CRP levels showed a high negative predictive value for excluding 30-day mortality (CRP <10 mg/L=100%, CRP <50=99.1%, CRP <100=98.9%, CRP <200=94.9%). Low admission CRP levels <100 mg/L were independently associated with reduced 30-day mortality (odds ratio [OR] 0.18; 0.04-0.85), P=.03; need for mechanical ventilation and/or inotropic support (OR 0.21; 0.14-0.4), P=.002; and complicated pneumonia (OR 0.05; 0.01-0.35), P=.003. A CRP that fails to fall by 50% or more within 4 days of admission is independently associated with increased 30 day mortality (OR 24.5; 6.4-93.4), P <.0001; need for mechanical ventilation and/or inotropic support (OR 7.1; 2.8-17.8), P <.0001 and complicated pneumonia (OR 15.4; 6.32-37.6), P <.0001.
Admission CRP <100 mg/L has reduced risk for 30-day mortality, need for mechanical ventilation and/or inotropic support, and complicated pneumonia. Failure of CRP to fall by 50% or more at day 4 leads to an increased risk for 30-day mortality, need for mechanical ventilation and/or inotropic support, and complicated pneumonia. C-reactive protein is an independent marker of severity in community-acquired pneumonia.
C反应蛋白（CRP）是肝脏主要在白细胞介素-6的刺激下合成的一种急性期蛋白。初步研究表明，炎症标志物可能在预测疾病严重程度方面发挥作用。我们研究了入院时及第4天的CRP水平是否能够预测社区获得性肺炎的严重程度。
在一家大型教学医院进行了一项为期2年的前瞻性研究。在入院时及第4天测量CRP水平。感兴趣的结局包括：30天死亡率；是否需要机械通气和/或使用血管活性药物支持；是否发生复杂性肺炎（肺脓肿、脓胸或复杂性类肺炎性胸腔积液）；使用多因素逻辑回归评估预测指标的价值。
本研究共纳入570例患者；30天死亡率为9.6%。低CRP水平对排除30天死亡率具有较高的阴性预测价值（CRP<10mg/L时为100%，CRP<50时为99.1%，CRP<100时为98.9%，CRP<200时为94.9%）。入院时CRP水平<100mg/L与30天死亡率降低独立相关（比值比[OR]0.18；0.04-0.85），P=0.03；与需要机械通气和/或血管活性药物支持相关（OR 0.21；0.14-0.4），P=0.002；与复杂性肺炎相关（OR 0.05；0.01-0.35），P=0.003。入院后4天内CRP未能下降50%或更多与30天死亡率增加独立相关（OR 24.5；6.4-93.4），P<0.0001；与需要机械通气和/或血管活性药物支持相关（OR 7.1；2.8-1
