Ognissanti Damiano, Bjurman Christian, Holzmann Martin J, Theodorsson Elvar, Petzold Max, Cvijovic Marija, Hammarsten Ola
Department of Mathematical Sciences, Chalmers University of Technology and the University of Gothenburg, SE-412 96 Gothenburg, Sweden.
Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, SE-41345 Gothenburg, Sweden.
Clin Biochem. 2019 Apr;66:21-28. doi: 10.1016/j.clinbiochem.2019.02.003. Epub 2019 Feb 4.
Myocardial infarction (MI) is more likely if the heart damage biomarker cardiac troponin T (cTnT) is elevated in a blood sample from a patient with chest pain. There is no conventional method to estimate the risk of MI at a specific cTnT concentration. The purpose of this study was to evaluate the performance of a novel method that converts cTnT concentrations to patient-specific risks of MI.
Admission cTnT measurements in 15,425 ED patients from three hospitals with a primary complaint of chest pain, with or without a clinical diagnosis of MI, were Box-Cox-transformed to normality density functions to calculate the percentage with MI among patients with a given cTnT concentration, the parametric predictive value among lookalikes (PALfx). The ability of the PALfx to generate stable risk estimates of MI was examined by bootstrapping and expressed as the coefficient of variation (CV).
Four age and sex-specific subgroups above or below 60 years of age with distinct cTnT distributions were identified among patients without MI. The cTnT distributions across subgroups with MI were similar, allowing us to use all admissions with MI to calculate the PALfx in the four subgroups. For instance, at a baseline cTnT concentration of 7 ng/L, a female patient <60 years would have a 0.5% risk of MI whereas a male patient >60 years would have a 1.9% risk of MI. To assess the stability of the PALfx method we bootstrapped smaller and smaller subsets of the 15,422 ED visits. We found that 1950 patients without MI and 50 patients with MI were sufficient to limit the variation of the PALfx with a CV of 0.8-5.4%, close to the CV using the entire dataset. The MI risk estimates were similar when data from the three hospitals were used separately to derive the PALfx equations.
The PALfx can be used to estimate the risk of MI at patient-specific cTnT concentrations with acceptable margins of error. The patient-specific risk of disease using the PALfx could complement decision limits.
对于胸痛患者的血液样本，如果心脏损伤生物标志物心肌肌钙蛋白T（cTnT）升高，则更有可能发生心肌梗死（MI）。目前尚无常规方法可在特定cTnT浓度下估算MI风险。本研究的目的是评估一种将cTnT浓度转化为患者特异性MI风险的新方法的性能。
对来自三家医院的15425例以胸痛为主诉的急诊患者（无论有无MI临床诊断）的入院时cTnT测量值进行Box-Cox变换，使其符合正态密度函数，以计算给定cTnT浓度患者中发生MI的百分比，即相似患者中的参数预测值（PALfx）。通过自抽样检验PALfx生成MI稳定风险估计值的能力，并以变异系数（CV）表示。
在无MI的患者中，确定了四个年龄和性别特异性亚组，年龄在60岁以上或以下，cTnT分布不同。有MI的亚组间cTnT分布相似，这使我们能够使用所有有MI的入院患者来计算四个亚组的PALfx。例如，在基线cTnT浓度为7 ng/L时，一名年龄<60岁的女性患者发生MI的风险为0.5%，而一名年龄>60岁的男性患者发生MI的风险为1.9%。为评估PALfx方法的稳定性，我们对15422次急诊就诊的越来越小的子集进行自抽样。我们发现对于PALfx的变异，1950例无MI患者和50例有MI患者就足够了，CV为0.8 - 5.4%，接近使用整个数据集时的CV。当分别使用三家医院的数据推导PALfx方程时，MI风险估计值相似。
PALfx可用于在患者特异性cTnT浓度下估算MI风险，误差幅度可接受。使用PALfx得出的患者特异性疾病风险可补充决策界限。
