© 2008 American Thoracic Society
Are GOLDen Slumbers Drug Induced?To the Editor:I thank Professor Fabbri for encouraging us in his September 15, 2007 editorial, to question authority (1), a concept that some Americans have embraced since the Vietnam War. Professor Fabbri, a former chair of the GOLD Scientific Committee (2), apparently wants to take the O out of COPD, by including patients without airway obstruction (a normal FEV1/FVC), but with a "clinical diagnosis of COPD." He provides a scattergram from an abstract that never made the transition to publication (3), finding that 14% of German patients with chronic cough or hyperinflation on chest radiograph had FEV1/FVC > 70%, but low FEV1. However, this pattern of spirometric restriction (not classified by the GOLD guidelines) is usually caused by submaximal inspiratory or expiratory effort on spirometry or by obesity. No evidence has been published that people with this pattern (or those in the old GOLD stage 0) are more likely than other smokers to subsequently experience a rapid fall in lung function (4). The retrospective, subgroup analysis of de Marco and coworkers (5) found that a few young smokers with chronic bronchitis and normal baseline spirometry had a prebronchodilator (pre-BD) FEV1/FVC < 0.70 about 8 years later, called "incident COPD" by the authors. This is not surprising since the razor-thin, arbitrary threshold could easily have been crossed with only a slight decrease in FEV1 or slight increase in FVC at the second survey (easily explained by within-subject reproducibility). In addition, about one-fourth of adults with GOLD stage 1 or 2 pre-BD don't have it post-BD (6), consistent with asthma as the cause of their pre-BD airway obstruction. The 40-year-old evidence that abnormal spirometry (a low FEV1 or low FVC) is an independent predictor of all-cause mortality does not make the faulty fixed 0.70 GOLD threshold clinically irrelevant. It is now time to replace the 0.70 (and 80% predicted) thresholds with the appropriate fifth percentile thresholds, before more damage is done (7). Telling patients (smokers or nonsmokers) that they have COPD when the probability is low has serious consequences for them and for society (8). I doubt that the American Thoracic Society can ever ethically endorse clinical practice guidelines entirely financed by an industry that profits greatly by influencing the diagnostic thresholds.
The University of Arizona College of Public Health FOOTNOTES Conflict of Interest Statement: P.L.E. has received a total of about $20,000 during the past 3 years from Pfizer and InterMune for reviewing the quality of pulmonary function tests done for clinical trials of patients with COPD or interstitial lung disease. REFERENCES
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