Response

Abstract

We appreciate the correspondence of Dr van Dijk on our study in CHEST,1Mohamed Hoesein FAA Zanen P Boezen HM et al.Lung function decline in male heavy smokers relates to baseline airflow obstruction severity.Chest. 2012; 142: 1530-1538Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar in which we examined lung function decline in three groups of heavy smokers classified by their baseline prebronchodilator FEV1/FVC: >70%, ≤70%, and less than the lower limit of normal. We believe that Dr van Dijk misinterpreted the outcomes reported in Table 4. As can be found in the “Materials and Methods” section,1Mohamed Hoesein FAA Zanen P Boezen HM et al.Lung function decline in male heavy smokers relates to baseline airflow obstruction severity.Chest. 2012; 142: 1530-1538Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar the decline was analyzed by multiple linear regression with the follow-up FEV1 as the dependent variable and the baseline FEV1, among others, as an independent variable. In our Table 4, the regression coefficients (β) of the significant independent variables are listed. Classically, in linear regression analysis, the independent variables are multiplied with their regression coefficient (βx), in this case, baseline FEV1 × 0.94. From this it can be easily concluded that a higher baseline FEV1 results in a lower follow-up FEV1, and not, as implied by Dr van Dijk, in preserving airflow. We corrected for smoking status and pack-years smoked, and, therefore, do not find it likely that our results can be explained by differences in smoking status. Moreover, in the patients with an FEV1/FVC <70% and less than lower limit of normal, pack-years smoked and number of current smokers was highest. Nonetheless, at the end, we agree with Dr van Dijk that lung function decline in our cohort of heavy smokers was substantial and that smoking cessation is one of the major interventions to address this. Role of sponsors: The sponsor had no role in the design of the study, the collection and analysis of the data, or in the preparation of the manuscript. Does Spirometry Still Measure Up in the Diagnosis of COPD?CHESTVol. 143Issue 1PreviewAn adequate and early diagnosis of COPD is essential for an appropriate and efficient treatment of this debilitating disease. Currently, spirometry is required to establish a diagnosis of COPD in patients with chronic respiratory symptoms or in those at risk.1 According to the results reported in CHEST (December 2012) by Mohamed Hoesein et al,2 this approach would misdiagnose an important group of patients who do not (yet) fulfill the spirometry diagnostic criteria; that is, among male heavy smokers, those with higher FEV1/FVC ratios may be the ones with the fastest FEV1 decline, a hallmark of COPD. Full-Text PDF