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Correspondence |

Longitudinal Assessment of Spirometry in World Trade Center Responders FREE TO VIEW

Albert Miller, MD, FCCP; Jack Mann, MD, FCCP
Author and Funding Information

Affiliations: Dr. Miller is affiliated with the New York Medical College. Dr. Mann is affiliated with the Weill Medical College of Cornell University.

Correspondence to: Albert Miller, MD, FCCP, Pulmonary Division, Dazian 7, Beth Israel Medical Center, First Ave at 16th St, New York, NY 10003; e-mail: almillermd@gmail.com


Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/site/misc/reprints.xhtml).


© 2009 American College of Chest Physicians


Chest. 2009;136(4):1182-1183. doi:10.1378/chest.09-0914
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Skloot and coworkers1 are commended for providing follow-up information on the spirometric findings in their large World Trade Center cohort, which they reported recently in CHEST (February 2009). A reader must be impressed by the finding of less than expected loss in FVC and FEV1 in this selected symptomatic population who had a high prevalence of spirometric abnormality to begin with. This finding consists of the following:

  1. An increase in spirometric values over 3 years in those patients who were initially responsive to therapy with bronchodilators (BDs); and

  2. A less than expected decrease in FVC and FEV1 in those patients who were not responsive to therapy with BDs, even in the oldest strata of patients.

Examination 1 was performed over a 2-year period beginning 10 months after the inciting event. Both of these considerations created a “baseline” in which pulmonary function would be expected to vary considerably, making comparison with subsequent results difficult to interpret.

A graphically striking finding shown in Figure 1 in the article by Skloot et al1 is that, given the variability in the change in FVC and FEV1 at examination 2, change is not skewed toward excessive loss, as would be seen when progressive impairment had developed in a significant portion of the subjects. Similarly impressive is the resolution of BD responsiveness in fully 72% of those subjects who were initially responsive to BDs. Since 9% of the group responded at examination 1 and 8% responded at examination 2, it is obvious that the two sets of responders were not the same. That the majority of those who were responsive to BDs were not responsive on follow-up is noteworthy. Equally noteworthy, the onset of BD responsiveness 32.4 months after the first test and 4 to 6 years after the initial insult at ground zero bears explanation and suggests that it is not attributable to this distant exposure.

The authors must align their conclusions with their data. In the Abstract of the article by Skloot et al,1 the authors state that “significant predictors of greater average decline were BD responsiveness at examination 1 …” and that “initial BD response [is] … associated with greater than normal lung function declines.” However, in the “Results” section they state that “BD responsiveness was associated with an increase in pre-BD spirometry,” which is clearly seen in Table 5 in the article.

The authors emphasize the “greater frequency of spirometric abnormalities [in their cohort] … compared to a general US population.” There is little justification in comparing a selected symptomatic group with a general population. As well, a more quantitative and clinically relevant definition of dyspnea than “persistent” would be appreciated.

Some of the change in spirometric values may relate to the spirometric technique that was used. The technique used may allow the measurement of a complete exhalation from less than full inspiratory capacity, thereby decreasing the FVC. This artifact is not always easy to detect on review of volume-time or flow-volume curves. Such a quality review is directed more at exhalation.

Nevertheless, the authors seem to confirm their reports of the frequency of low FVC without low FEV1/FVC ratio. That this spirometric pattern has been associated with a syndrome of airways dysfunction clinically characterized as irritant-aggravated or irritant-induced asthma, or reactive airways dysfunction syndrome adds to the experience with this pattern of impairment that was first described for patients with asthma.2,3

Financial/nonfinancial disclosures: The authors have reported to the ACCP that no significant conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Skloot GS, Schechter CB, Herbert R, et al. Longitudinal assessment of spirometry in the World Trade Center Medical Monitoring Program. Chest. 2009;135:492-498. [PubMed] [CrossRef]
 
Miller A. A simple spirometric clue to asthma: airways obstruction suggested by a negative or reduced forced expiratory reserve volume despite normal FEV1/FVC ratio. Mt Sinai J Med. 1990;57:85-92. [PubMed]
 
Miller A, Palecki A. Restrictive impairment in patients with asthma. Respir Med. 2007;101:272-276. [PubMed]
 

Figures

Tables

References

Skloot GS, Schechter CB, Herbert R, et al. Longitudinal assessment of spirometry in the World Trade Center Medical Monitoring Program. Chest. 2009;135:492-498. [PubMed] [CrossRef]
 
Miller A. A simple spirometric clue to asthma: airways obstruction suggested by a negative or reduced forced expiratory reserve volume despite normal FEV1/FVC ratio. Mt Sinai J Med. 1990;57:85-92. [PubMed]
 
Miller A, Palecki A. Restrictive impairment in patients with asthma. Respir Med. 2007;101:272-276. [PubMed]
 
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