From the authors:
We would like to thank D.R. Taylor and J. Dummer for their comments on our recent paper 1. In the paper, we reported that higher bronchial nitric oxide flux (J′aw,NO) values were associated with more likely symptom relief during fluticasone treatment in patients with chronic obstructive pulmonary disease (COPD). We agree with D.R. Taylor and J. Dummer that positive and negative predictive values (PPV and NPV, respectively) for certain cut-off points of J′aw,NO would help the clinician to judge the applicability of J′aw,NO to predict steroid-responsiveness in COPD.
We have now reanalysed the data (using SPSS 12.0.1 software; SPSS Inc., Chicago, IL, USA) by using receivers operating characteristics. Baseline J′aw,NO was a significant predictor of symptom relief during fluticasone treatment (area under the curve 0.722; p = 0.018). At a cut-off point of 0.7 nL·s−1, PPV for symptom relief was 83% and NPV was 56%, suggesting that at this cut-off point J′aw,NO is a moderately accurate predictor of good treatment response but not a useful measure to exclude symptom relief.
Footnotes
Statement of Interest
Statements of interest for all authors of this manuscript can be found at www.erj.ersjournals.com/misc/statements.dtl
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