Response

Abstract

We thank Sakhamuri and Chattu for their comments on our study.1Raymakers A.J.N. Sadatsafavi M. Sin D.D. De Vera M.A. Lynd L.D. The impact of statin drug use on all-cause mortality in patients with COPD: a population-based cohort study.Chest. 2017; 152: 486-493Abstract Full Text Full Text PDF PubMed Scopus (34) Google Scholar The main criticisms raised in their letter were the following: (1) the age restriction for the cohort of patients with COPD clashes with the literature we cited; (2) the cohort was restricted to those without previous cardiovascular disease (CVD); and (3) the case definition for COPD was based on filled prescriptions for COPD-related, albeit not COPD-specific, medications. We appreciate these concerns and contend that they are largely limitations of administrative data and that we have appropriately identified and responded to these criticisms in our article (see the Discussion section); we do, however, address each point specifically here. First, there were concerns that in the beginning of our paper we referred to a population of patients with COPD who were > 30 years of age whereas our study used an age criterion of 50 years of age or older. The impetus for imposing such a restriction was, given that our study used administrative data, to enhance the likelihood that included patients had COPD by acknowledging that this disease typically occurs in older adults. Second, we chose not to restrict the cohort of patients with COPD to those without a history of CVD. This was addressed in our article and the decision contextualized using the results of the Simvastatin in the Prevention of COPD Exacerbations (STATCOPE) trial.2Criner G.J. Connett J.E. Aaron S.D. et al.Simvastatin for the Prevention of exacerbations in moderate-to-severe COPD.N Engl J Med. 2014; 370: 2201-2210Crossref PubMed Scopus (250) Google Scholar Although the STATCOPE trial removed patients meeting this criterion, it was our contention that this may have removed those patients with COPD in whom we would have expected statin drugs to confer benefit (see the Discussion section of our article). The hypothesized mechanism by which statin drugs might reduce poor outcomes in patients with COPD is largely unknown but may occur by downregulating systemic inflammation, which has been linked to an increased risk of CVD.3Sin D.D. Why are patients with chronic obstructive pulmonary disease at increased risk of cardiovascular diseases? The Potential role of systemic inflammation in chronic obstructive pulmonary disease.Circulation. 2003; 107: 1514-1519Crossref PubMed Scopus (912) Google Scholar, 4Agusti A. Faner R. Systemic inflammation and comorbidities in chronic obstructive pulmonary disease.Proc Am Thorac Soc. 2012; 9: 43-46Crossref PubMed Scopus (58) Google Scholar Therefore, it was important for these patients to remain in the cohort of patients with COPD. The final point raised by the authors takes issue with our case definition of COPD. We defined patients with COPD as those who filled a series of prescriptions for anticholinergics or short-acting beta-agonists. We appreciate the concern that this is an imperfect definition of COPD and that it would be ideal if our data contained an individual assessment of pulmonary function with spirometry. Similar to our earlier statement, this is a limitation of the data used in our study, and the absence of such clinical assessments is typical in studies that use administrative data. Although we acknowledge the limitations of the data, we assert that the population-based nature of the data is also a significant strength of our study and is better reflective of the “real world” than are data from randomized controlled trials. Therefore, we believe that our results highlight a potential beneficial effect of statin drugs to certain patients with COPD and that this work will hopefully motivate future research to properly identify this specific subgroup. Statins in COPD: Selection Modalities and MortalitiesCHESTVol. 153Issue 2PreviewCardiovascular disease contributes a significant share to the all-cause mortality of COPD1; therefore it is sensible to assume similar positive outcomes with its mortality benefiting measures in the COPD group as well. The study by Raymakers et al2 published in CHEST (September 2017) found a significant all-cause and COPD-related mortality benefit with the use of statin drugs. The inclusion of a vast number of participants from databases, with a follow-up of a reasonable duration and a focus on adherence to statin drug use are the strengths of this retrospective study. Full-Text PDF The Impact of Statin Drug Use on All-Cause Mortality in Patients With COPD: A Population-Based Cohort StudyCHESTVol. 152Issue 3PreviewPatients with COPD are often prescribed statin drugs due to the increased prevalence of cardiovascular disease. There is considerable debate about the benefits conferred by statin drugs in patients with COPD. This study evaluates the association of statin drug use with all-cause and lung-related mortality in patients with COPD. Full-Text PDF