Journal Club Summary

Methodology Score: 2.5/5
Usefulness Score: 3/5

Prins HJ, et al. Eur Respir J. 2019 May 23;53(5). 

Question and Methods: The CATCH Study was a multicentre, randomised, controlled open intervention clinical trial comparing CRP guided antibiotics for COPDE vs the Gold Strategy

Findings: The study had a 14.5% AAR in antibiotic use within 24 hours with a NNT of 6.9

Limitations: The major flaw in the study was that the groups were not prognostically balanced due to a poor randomization strategy with block sizes of 50.

Interpretation: This paper provides evidence that CRP may be a useful tool in treating AECOPD, however, CATCH is a small trial with major methodological flaws and currently shouldn’t guide practice.

By: Dr. Harrison Carmichael


Epi Lesson

Number Needed to Treat (NNT)

The NNT concept was created by Canadian Clinical Epidemiologist Dr Andreas Laupacis in 1988 to quantify the benefit of a new intervention.  NNT is the average number of patients who need to be treated to prevent one additional bad outcome (e.g. the number of patients that need to be treated for one to benefit compared with a control in a clinical trial). It is easily calculated as the inverse of the absolute risk reduction (1/ARR). The higher the NNT the less effective the treatment.

By: Dr. Ian Stiell


  • Hans Rosenberg

    Dr. Rosenberg is an emergency physician at the Ottawa Hospital, assistant professor at the University of Ottawa, and Director of the Digital Scholarship and Knowledge Dissemination Program.

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