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Tucson, AZ
Dr. Enright is Research Professor of Medicine and Public Health, University of Arizona Mel and Enid Zuckerman College of Public Health.
Correspondence to: Paul Enright, MD, 4460 East Ina Rd, Tucson, AZ 85718; e-mail: LungGuy{at}aol.com
Congratulations to the investigators of the Spirometry in Asthma and COPD: a Comparative Evaluation (SPACE) program for carefully describing the excellent methods, but disappointing results, of their Italy-wide study to determine whether office spirometry performed by general practitioners (GPs) improves the diagnosis of asthma and COPD.1 Since 2003, similar projects have been generously funded in the United States. The SPACE program, which enrolled 570 GPs, with spirometry training provided by 57 pulmonary specialists, did not find a significant advantage of office spirometry in improving the diagnosis of asthma and COPD in the primary care setting. However, a type II error cannot be excluded, since the enrollment of participating patients reached only about half of the goal determined by a priori sample size calculations.
For several decades, I have personally been involved in promoting the idea that primary care providers (PCPs) [or GPs] should perform spirometry in their office.2 In 2000, the National Lung Health Education Program recommended3 office spirometry for COPD case-finding for adult smokers being seen by their PCP. Since then, tens of millions of dollars have been spent by industry for both COPD case-finding in PCP settings and for screening programs designed to test very large samples of the general populations of cities or entire countries for airway obstruction.4 During the same period of time, the definition of COPD has been considerably broadened by the criteria of the Global Initiative for Chronic Obstructive Lung Disease guidelines (FEV1/FVC ratio, < 70% [regardless of age and FEV1 percent predicted]),5 so that two to three times the number of people from a population sample of adults now fit the new definition when compared to traditional definitions.678
So, why should I now argue with success? What possible harm could be done by the widespread application of spirometry to detect COPD in its early stages? Members of the National Lung Health Education Program recognized the weak evidence base > 5 years ago and called for well-designed studies to determine whether PCPs could achieve acceptably low misclassification rates for airway obstruction when using simple office spirometers, and whether knowledge of spirometry results substantially improves smoking cessation rates.9 A new report10 from the Agency for Healthcare Research and Quality (AHRQ) emphasizes that this essential evidence remains lacking and goes further to state that no inhaled medications have been demonstrated to improve COPD outcomes when prescribed to patients with an FEV1 of > 50% predicted (Global Initiative for Chronic Obstructive Lung Disease stages 0, 1, and 2); and that many patients have been prescribed inhaled medications for COPD, chronic bronchitis, or emphysema, yet have entirely normal spirometry findings. The financial implications of these recommendations and guidelines are enormous. Long-acting bronchodilators (and ultra-long-acting bronchodilators) and inhaled corticosteroids that have been prescribed for the treatment of COPD have worldwide annual markets in the tens of billions of dollars, and cost about $100 per month for each elderly patient without insurance coverage.
Older adults in whom COPD has developed due to smoking often have either a recognized or a subclinical comorbidity (eg, cardiovascular disease, glucose intolerance, osteoporosis, and ophthalmic disease) that makes serious side effects, such as malignant arrhythmias and osteoporotic fractures, more likely when receiving long-term therapy with these inhaled medications11121314 and, at best, temporarily reduces dyspnea on exertion in some patients with severe airway obstruction. Smokers and PCPs may also think that an inhaled medication is a substitute for smoking cessation. Thus, psychological, economic, and physical harm are all possible when an "abnormal" spirometry result usually leads to a prescription for an inhaled medication in an adult smoker (with or without chronic cough, phlegm, or wheeze). On a population-wide basis, the possible benefits of the increased likelihood of smoking cessation, temporary symptomatic relief, and slightly reduced risk of a COPD exacerbation may not overcome the costs of testing and treating, and the drug side-effects.10 However, the risk/benefit ratio may be better for individually selected patients and those who also have asthma.
The results of the SPACE study1 (see page 844) suggest that problems with office spirometry will remain even if medications for COPD are developed that substantially improve the course of COPD in its early stages, or if future studies demonstrate that knowledge of abnormal spirometry results substantially prompts physicians to offer more effective smoking-cessation interventions, and prompts patients to successfully quit smoking. Even when offered free training by local pulmonary specialists, free spirometers, and free spirometry supplies, only a fraction of GPs are interested in testing, and, of those GPs who are interested, only a small fraction of adult smokers (or asthmatic patients) in their practice are tested, even during the first few months of enthusiasm. Most quit performing spirometry tests altogether. Furthermore, the long-term accuracy of the office spirometers was not evaluated; the misclassification rates were not determined; and the cost, benefits, adherence, and side effects of the resulting interventions were not measured in this study.
I now agree with the authors of the superb AHRQ report10 that, until more conclusive studies are performed, spirometry should currently be offered only to those smokers with dyspnea on exertion, and that therapy with inhaled medications should be reserved for those patients with a large bronchodilator response (suggesting asthma), relief of dyspnea, or severe airway obstruction (ie, FEV1 < 50% predicted) with a recent exacerbation that suggests a high risk of hospitalization during the subsequent year. The AHRQ report10 quotes large epidemiologic surveys showing that a surprising fraction of patients with a diagnosis of COPD have normal spirometry findings (ie, normal FEV1/FVC ratio and a normal FEV1). Spirometry may add more value when the lack of airway obstruction (after therapy with albuterol) is used to rule out COPD, than it does to confirm COPD in a smoker with respiratory symptoms. Substantial financial savings and a reduction in serious drug side effects would result for both the misclassified individual patients and entire countries if severe airway obstruction were routinely confirmed before the prescription of chronically inhaled medications for COPD.
Perhaps the focus should shift for a few years from trying to convince PCPs to perform spirometry in their office to providing high-quality (accredited) respiratory care services in each community,15 to which PCPs can refer their patients with dyspnea due to asthma or COPD. These services could include convenient smoking-cessation programs, asthma education, spirometry, allergen skin testing, exhaled nitric oxide measurements, pulmonary rehabilitation, long-term oxygen therapy, and chronic disease management, all following evidence-based clinical practice guidelines. The AHRQ report10 should also prompt the National Heart, Lung, and Blood Institute to place a high priority on the funding of a large multicenter study to determine whether spirometry enhances the best practice of smoking cessation in the primary care setting.
References
This article has been cited by other articles:
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  P. Enright and P. Quanjer Spirometry for COPD Is Both Underutilized and Overutilized Chest, August 1, 2007; 132(2): 368 - 370. [Full Text] [PDF]
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T. L. Petty Harm from spirometry? Chest, November 1, 2006; 130(5): 1629 - 1630. [Full Text] [PDF]
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