Association is Not the Same as Accuracy

Accuracy; Grace score; TIMI score; Coronary anatomy

Dear Editor,

In a recent article, dos Santos et al. have concluded that, for patients with acute coronary syndromes, risk scores correlated with coronary artery disease severity¹. That apparently positive conclusion hides the poor performance of those scores to predict obstructive coronary artery disease due to two reasons. Firstly, in face of a diagnostic situation (presence of coronary artery disease ≥ 50%), the clinical focus should be on accuracy. Secondly, association (described in the article as correlation) does not ensure accuracy.

The major focus of that study should have been accuracy measures, such as area under the ROC curve, ranging from 0.56 to 0.70. Although statistically significant, those values indicate low accuracy from the diagnostic viewpoint. Corroborating those findings, in a recently published article in this same journal, our group has concluded that the degree of association (between scores and coronary anatomy) is not sufficient for risk scores to accurately predict the results of angiography².

The different conclusions from two studies of similar findings is due to the perception that statistical significance (true association) and clinical relevance (accuracy) do not exactly represent the same phenomenon.

Referências

• ¹
  dos Santos ES, Aguiar Filho Lde F, Fonseca DM, Londero HJ, Xavier RM, Pereira MP, et al. Correlation of risk scores with coronary anatomy in non-STelevation acute coronary syndrome. Arq Bras Cardiol. 2013;100(6):511-7.
• ²
  Barbosa CE, Viana M, Brito M, Sabino M, Garcia G, Maraux M, et al. Accuracy of the GRACE and TIMI scores in predicting the angiographic severity of acute coronary syndrome. Arq Bras Cardiol. 2012;99(3):818-24.

Publication Dates

• Publication in this collection
  Jan 2014

History

• Received
  30 July 2013
• Reviewed
  03 Sept 2013
• Accepted
  04 Sept 2013