Chronic Obstructive Pulmonary Diseases:Journal of the COPD Foundation

Running Head: Author Response

Abbreviations: chronic obstructive pulmonary disease, COPD; flow-mediated dilation, FMD

Citation: Kim JS, Barr RG. Letter to the editor: response by authors. Chronic Obstr Pulm Dis. 2021; 8(2): 188-189. doi:

To the Editor

We appreciate the comments by Dr. Theodorakopoulou and colleagues regarding our pilot randomized clinical trial.1 We agree with the authors that our findings are focused on moderate-to-severe chronic obstructive pulmonary disease (COPD) and that the role of omega-3 fatty acids on endothelial function in less severe COPD patients was not examined, a point we highlighted in the discussion. As the authors point out, we acknowledged the imbalance of characteristics between the placebo and fish oil groups as a limitation in the discussion that may have impacted our study’s findings, along with the absence of significant lowering of triglycerides in the fish oil arm. We thank them for the suggestion to perform a post-hoc analysis as we adjusted for statin and calcium-channel blocker use for the primary outcome of percentage change in flow-mediated dilation (FMD) from baseline to 6 months, which also yielded null results: mean percentage difference of -1.1 (95% CI -5.7 to 3.5, p=0.65). Unfortunately, we did not have additional information on other healthy lifestyle choices, which might have affected results albeit less likely in a randomized clinical trial.

We did not report p values in Table 1 as doing so is not recommended by CONSORT guidelines2; baseline differences in this small randomized clinical trial likely were due to chance, obviating the need for p values in Table 1. Unfortunately, we did not have other FMD-related measures such as hyperemia-induced shear stress assessed but this may be a future area of research related to omega-3 fatty acids and endothelial function in COPD. Collectively these gaps in our study, that are highlighted by Theodorakopoulou, et al, point to future areas of research to investigate the utility of omega-3 therapies for endothelial function in adults with COPD.

1. Kim JS, Thomashow MA, Yip NH, et al. Randomization to omega-3 fatty acid supplementation and endothelial function in COPD: the COD-Fish randomized controlled trial. Chronic Obstr Pulm Dis. 2021;8(1):41-53. doi:

2. Moher D, Hopewell S, Schulz KF, et al. CONSORT 2010 explanation and elaboration: updated guidelines for reporting parallel group randomised trials. BMJ. 2010;340:c869. doi:

Posted in: Perspectives, Volume 8 | Issue 2

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