Division of Preventive Medicine, University of Alabama at Birmingham School of Medicine, Medical Towers 621, 1717 11th Avenue South, Birmingham, AL 35294-4410, USA.
BMC Health Serv Res. 2013 May 1;13:162. doi: 10.1186/1472-6963-13-162.
International guidelines recommend that the decision threshold for troponin should be the 99th percentile of a normal population, or, if the laboratory assay is not sufficiently precise at this low level, the level at which the assay achieves a 10% or better coefficient of variation (CV). Our objectives were to examine US hospital laboratory troponin reports to determine whether either the 99th percentile or the 10% CV level were clearly indicated, and whether nonconcordance with these guidelines was a potential barrier to detecting clinically important microscopic or 'microsize' myocardial infarctions (MIs). To confirm past reports of the clinical importance of microsize MIs, we also contrasted in-hospital, 28-day and 1-year mortality among those with microsize and nonmicrosize MI.
In the REasons for Geographic And Racial Differences in Stroke national prospective cohort study (n=30,239), 1029 participants were hospitalized for acute coronary syndrome (ACS) between 2003-2009. For each case, we recorded all thresholds of abnormal troponin on the laboratory report and whether the 99th percentile or 10% CV value were clearly identified. All cases were expert adjudicated for presence of MI. Peak troponin values were used to classify MIs as microsize MI (< five times the lowest listed upper limit of normal) and nonmicrosize MI.
Participants were hospitalized at 649 acute care US hospitals, only 2% of whose lab reports clearly identified the 99th percentile or the 10% CV level; 52% of reports indicated an indeterminate range, a practice that is no longer recommended. There were 183 microsize MIs and 353 nonmicrosize MIs. In-hospital mortality tended to be lower in the microsize than in the nonmicrosize MI group (1.1 vs. 3.6%, p = 0.09), but 28-day and 1-year mortality were similar (2.5% vs. 2.7% [p = 0.93] and 5.2% vs. 4.3% [p = 0.64], respectively).
Current practices in many US hospitals created barriers to the clinical recognition of microsize MI, which was common and clinically important in our study. Improved hospital troponin reporting is warranted.
国际指南建议肌钙蛋白的决策阈值应为正常人群的第 99 百分位，或者如果实验室检测在低水平下不够精确，则应在检测达到 10%或更高变异系数（CV）的水平。我们的目的是检查美国医院实验室的肌钙蛋白报告，以确定是否明确指出了第 99 百分位或 10%CV 水平，以及与这些指南的不一致是否是检测临床重要的微小心肌梗死（MI）的潜在障碍。为了证实过去关于微小心肌梗死临床重要性的报告，我们还比较了微小心肌梗死和非微小心肌梗死患者的住院、28 天和 1 年死亡率。
在地理和种族差异导致中风的原因国家前瞻性队列研究（n=30239）中，2003-2009 年间有 1029 名参与者因急性冠状动脉综合征（ACS）住院。对于每个病例，我们记录了实验室报告中所有异常肌钙蛋白的阈值，以及是否明确指出了第 99 百分位或 10%CV 值。所有病例均由专家进行了 MI 存在的裁决。肌钙蛋白峰值用于将 MI 分类为微小心肌梗死（<五个最低列出的正常上限）和非微小心肌梗死。
参与者被收入了美国 649 家急性护理医院，只有 2%的实验室报告明确指出了第 99 百分位或 10%CV 水平；52%的报告表明存在不确定范围，这种做法已不再被推荐。有 183 例微小心肌梗死和 353 例非微小心肌梗死。住院期间，微小心肌梗死组的死亡率低于非微小心肌梗死组（1.1% vs. 3.6%，p=0.09），但 28 天和 1 年死亡率相似（2.5% vs. 2.7%[p=0.93]和 5.2% vs. 4.3%[p=0.64]）。
目前许多美国医院的实践为临床识别微小心肌梗死制造了障碍，而在我们的研究中，微小心肌梗死很常见且具有临床重要性。需要改进医院肌钙蛋白报告。
